A Clinical Approach for Healthcare Providers in Pain Pharmacology

Learn about pain pharmacology from a clinical perspective and its role in modern pain management for individuals.

Abstract

This educational post provides a comprehensive overview of contemporary pharmacological strategies for pain management, presented from an integrative and functional medicine perspective. My name is Dr. Alex Jimenez, and throughout my career, I have dedicated myself to understanding the intricate mechanisms of pain and developing holistic treatment plans. This article synthesizes the latest findings from leading researchers, translating complex pharmacological concepts into an accessible journey for both patients and healthcare professionals. We will explore the critical role of the cytochrome P450 system in opioid metabolism, dissect the mechanisms of anticonvulsants and antidepressants in modulating chronic pain, and examine how to construct a multi-medication regimen strategically. A significant focus will be on the practical application of this knowledge, including a detailed look at common over-the-counter and prescription medications like acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), muscle relaxants, topical agents, and advanced therapies like low-dose naltrexone. We will highlight their efficacy, risks, and often-overlooked clinical nuances.

Furthermore, this post will illuminate the unique multidisciplinary framework of our practice, Injury Medical Clinic PA. We will discuss how our integrated team, under the medical direction of Dr. Maria Guadalupe Cardenas, MD, a highly experienced, board-certified internist, synergizes integrative chiropractic care, functional medicine, medical oversight, and rehabilitation. This collaborative model is central to our philosophy of providing patient-centered, evidence-based care that addresses the root causes of pain and promotes long-term well-being, moving beyond mere symptom management.

Our Integrative Practice: A Collaborative Model for Comprehensive Care

Before we delve into the specifics of pharmacology, I want to provide some context about our approach at Injury Medical Clinic PA in El Paso, Texas. I am Dr. Alex Jimenez, and I hold dual credentials as a Doctor of Chiropractic (DC) and an Advanced Practice Registered Nurse (APRN), certified as a Family Nurse Practitioner (FNP-BC). My passion for understanding the body as an interconnected system has led me to further specialize as a Certified Functional Medicine Practitioner (CFMP) and an Institute for Functional Medicine Certified Practitioner (IFMCP).

Our clinic operates on a deeply collaborative, multidisciplinary model, which is fundamental to how we manage complex conditions like chronic pain. A cornerstone of this model is my professional relationship with Dr. Maria Guadalupe Cardenas, MD. Dr. Cardenas is a board-certified internist with over four decades of clinical experience (NPI #1164426749; Texas MD License #J2933). She serves as our Medical Director and Collaborative Physician at Injury Medical Clinic PA (also known as Mission Plaza Injury Medical Clinic), providing essential medical oversight and guidance. This structure, where a medical doctor works in tandem with a chiropractor and other specialists, is common in progressive integrative and injury care settings. It allows us to bridge the gap between different healthcare disciplines, ensuring our patients receive the most comprehensive and safest care possible.

Our team integrates a wide spectrum of services:

• Chiropractic Care: I provide spinal adjustments, soft tissue therapies, and biomechanical corrections to address musculoskeletal imbalances, nerve impingement, and structural issues that are often the root cause of pain.
• Medical Oversight (Dr. Cardenas): Dr. Cardenas oversees the medical aspects of patient care, including the appropriateness of pharmacological interventions, managing comorbidities, and ensuring all treatments align with established medical standards. Her extensive experience in internal medicine is invaluable in navigating the complexities of patients with multiple health issues.
• Functional Medicine: We use a systems-biology approach to identify and address the underlying causes of disease. This involves detailed patient histories, advanced lab testing (genomics, metabolomics), and personalized plans focusing on nutrition, lifestyle, and targeted supplementation.
• Pharmacological Management: When medications are necessary, we approach them with a deep understanding of their mechanisms, risks, and interactions, as we will discuss in this post. This is managed collaboratively between myself as an FNP and under the guidance of Dr. Cardenas.
• Rehabilitation and Personal Injury Care: We develop customized rehabilitation programs to restore function, improve strength and mobility, and help patients recover from injuries, whether from an auto accident, a workplace incident, or a sports-related trauma.

This integrated model allows us to create a truly patient-centered journey. A patient might come to us with debilitating low back pain. In our clinic, they would receive a comprehensive evaluation that includes a chiropractic assessment of their spinal alignment, a functional medicine workup to investigate systemic inflammation, and a medical review by Dr. Cardenas to rule out other pathologies and oversee any necessary prescriptions. The treatment plan could involve chiropractic adjustments to decompress the spine, a functional nutrition plan to reduce inflammation, targeted physical therapy to strengthen core muscles, and, if necessary, a carefully selected medication to manage acute pain while the other therapies take effect. This is the power of integrative care—treating the whole person, not just the symptom. You can explore more of my clinical writings and case reflections at my website, WellnessDoctorRx.com, and on my LinkedIn profile for ongoing clinical insights.

Setting the Stage: The Importance of Patient Expectations in Pain Management

Before we begin our exploration of pharmacology, it’s crucial to address a foundational element of successful pain care: managing patient expectations. I’ve worked in interventional and integrative pain management for over two and a half decades, and if there’s one lesson that has been reinforced time and time again, it’s that pain management is a process, not a pill.

This isn’t just a catchy phrase; it’s a clinical reality. The journey to controlling chronic pain is often long and involves multiple strategies. However, many patients, understandably desperate for relief, arrive with the expectation of a quick fix. This disconnect between expectation and reality can be a significant barrier to success.

A fascinating, and frankly startling, study revealed a profound insight into the patient mindset. Researchers examining patient expectations found that many individuals equated anything less than 100% pain relief with the withholding of care. This “all-or-nothing” perspective is not only a disservice to the dedicated healthcare providers working to help them but, more importantly, a disservice to the patients themselves. It traps them in a cycle of disappointment and prevents them from recognizing meaningful progress.

In the world of clinical research, a 30% to 60% improvement in pain scores is considered a clinically significant outcome. Now, I understand that if you were paying for a service and were told you’d only get a 30% return on your investment, you’d be skeptical. This is precisely why a multimodal approach is not just beneficial—it’s essential. If we can achieve a 30% reduction from one therapy (like chiropractic care), 20% from a nutritional intervention, and perhaps another 30% from a carefully chosen medication, we can start to “chip away” at the pain in a substantial way. The sum of these parts often leads to a transformative improvement in a person’s quality of life.

Measuring Success Beyond the 0-10 Scale

This brings me to another critical point: how we measure success. The ubiquitous 0-to-10 pain scale, while a required tool for documentation, is a woefully inadequate measure of a person’s lived experience. It fails to capture the nuance of function.

Let me ask you this: what’s the difference between a patient who rates their pain as a “10” while lying on the couch, unable to move, and a patient who rates their pain as a “10” after spending an afternoon walking around the mall with their granddaughter for the first time in years? The number is the same, but the stories behind them are worlds apart. The second patient, despite their pain score, has achieved a monumental victory in function and quality of life.

This is why we must shift the focus from a simple number to functional goals.

• Brief Pain Inventory (BPI): This is a validated, seven-question tool that I often use in my practice. It goes beyond intensity to assess how pain interferes with mood, mobility, work, social relationships, and sleep. The averaged score provides a much richer picture of the pain’s true impact.
• Patient-Identified Goals: Even more powerfully, we can work directly with patients to identify their personal goals. What does “better” mean to them?

• • “I want to be able to sleep through the night without waking up in pain.”
  • “I want to be able to walk my dog around the block.”
  • “I want to sit through my daughter’s dance recital without having to get up and move constantly.”

By defining these concrete, personal goals at the outset, we create a meaningful benchmark for success. We must document these goals and revisit them regularly. This process not only helps us gauge the effectiveness of our treatment plan but also empowers the patient. It helps them see and appreciate the incremental progress they are making, shifting their perspective from frustration to hope and accomplishment. This is the true measure of whether our interventions are working.

A Closer Look at Common Analgesics: Acetaminophen

Let’s begin our pharmacological journey with one of the most widely used medications in the world: acetaminophen (Tylenol). It’s so common that we often take its mechanisms and risks for granted. What I find truly mind-blowing, from a scientific standpoint, is that even after decades of use, the precise mechanism of action of acetaminophen is not fully understood. It is believed to work primarily within the central nervous system, possibly by inhibiting cyclooxygenase (COX) enzymes in the brain and activating descending serotonergic pathways, but the full picture remains elusive.

What is crystal clear, however, are the dangers of overdose. We all know that exceeding the maximum recommended dose can lead to severe hepatotoxicity (liver damage). The established limit is generally 4 grams (4,000 mg) per 24 hours. The problem is that while we, as clinicians, are aware of this, public understanding is dangerously inconsistent.

The statistics are sobering:

• Approximately 30,000 patients are hospitalized annually in the United States due to acetaminophen-induced liver toxicity.
• Shockingly, half of all acetaminophen overdoses are unintentional.

This happens because acetaminophen is a hidden ingredient in hundreds of over-the-counter products, including cold and flu remedies, sinus medications, and combination pain relievers. A patient might take the maximum dose of Tylenol for a headache while also taking a multi-symptom cold medicine for a cough, completely unaware that they are doubling their intake and venturing into toxic territory. This is why patient education campaigns like “Know Your Dose” are so vital. We have a responsibility to have explicit conversations with our patients about all the medications they are taking, both prescription and over-the-counter.

In the context of chronic pain, particularly low back pain, the evidence for acetaminophen’s efficacy is not particularly strong. However, this is where clinical judgment and individual patient response become key. I have had patients in my practice with severe, “terrible” findings on their MRI scans—significant disc herniations, spinal stenosis—who have found remarkable relief with a simple regimen of two regular-strength Tylenol tablets twice a day.

This highlights a fascinating dichotomy in patient perception. On one end of the spectrum, we have individuals who are completely unaware of the risks of liver toxicity. On the other end, we have patients who are so fearful that they believe taking two pills a day, with no other risk factors, will inevitably destroy their liver. Our role is to find the middle ground: to educate on the real risks without inducing unnecessary fear and to remember that for some individuals, this simple, readily available medication can be a safe and effective part of their pain management plan, especially if they have not tried it consistently before.

The Double-Edged Sword: Non-steroidal Anti-inflammatory Drugs (NSAIDs)

From acetaminophen, we naturally transition to another cornerstone of pain management:non-steroidal anti-inflammatory drugs (NSAIDs). We often think of these as a go-to option when acetaminophen isn’t enough, and indeed, they can be incredibly effective. However, their use is fraught with significant risks that are often underestimated by both patients and, at times, providers.

Recent research continues to highlight these concerns. We now understand that chronic NSAID use can lead to an increased risk of severe cardiovascular events. This isn’t a minor concern; we are talking about an elevated risk for heart failure, myocardial infarction (heart attack), and peripheral vascular disease. The list of potential complications doesn’t stop there. Gastrointestinal bleeding, kidney damage, and liver toxicity are also well-documented risks. The conclusion is undeniable: these are not benign substances when used chronically. This reality underscores a fundamental principle of our integrative approach: we must be vigilant and proactive in monitoring our patients.

Key Principles and Clinical Pearls for NSAID Use

Let’s break down some essential, and perhaps surprising, facts about NSAIDs.

• Efficacy is Not Class-Specific: In large-scale clinical trials, no single NSAID has been proven to be more efficacious than another. This is a crucial point. A patient may not respond to ibuprofen, but that doesn’t mean the entire class of drugs is ineffective for them. They might have a fantastic response to naproxen, diclofenac, or meloxicam.
• Individual Response is Variable: People can fail trials of one, two, or even three different NSAIDs before finding one that provides benefit. This underscores the importance of setting expectations. When I prescribe an NSAID, I tell my patient, “We are going to try this one first. It may not be the right fit for you. A true trial requires taking it consistently as prescribed for at least four days. If it doesn’t work, or if you have side effects, we have many other options in this same family of medications that we can try.” This reframes a “failed” trial as a data point, not a dead end.
• Special Consideration: Celecoxib (Celebrex) and Anticoagulants: We are all taught to avoid NSAIDs in patients on anticoagulants (like warfarin or a DOAC) due to the increased risk of bleeding. Most NSAIDs inhibit platelet aggregation, which, combined with an anticoagulant, can be a dangerous combination. However, celecoxib (Celebrex) is a notable exception. Because it is a COX-2 selective inhibitor, it does not have the same significant effect on platelets. This makes it a potentially safer option for a patient with arthritis who also requires anticoagulation, although caution is still warranted.

The Systemic Nature of GI Risk

This is one of the most misunderstood aspects of NSAIDs. Many people believe that the gastrointestinal (GI) side effects, like ulcers and bleeding, are caused by the pill physically irritating the stomach lining. They think that taking the medication with food will solve the problem. While taking it with food can help with general stomach upset, it does not protect against the primary mechanism of NSAID-induced GI damage.

The damage is a systemic effect, not a localized one. Here’s how it works:

1. Prostaglandins and Inflammation: NSAIDs work by blocking cyclooxygenase (COX) enzymes, which are responsible for producing prostaglandins. Certain prostaglandins are key mediators of the inflammatory cascade, causing pain, swelling, and fever. By blocking their production, NSAIDs reduce inflammation and pain.
2. Prostaglandins and Gastric Protection: However, other prostaglandins play a vital, protective role in the body. Specifically, they are responsible for maintaining the integrity of the gastro-protective mucosal layer that lines the stomach and the rest of the GI tract. This layer shields the delicate tissues from the harsh acidic environment of the stomach.
3. The Systemic Conflict: When you take an NSAID, it enters your bloodstream and travels throughout your body. It systemically blocks prostaglandin production everywhere—in your inflamed knee, but also in the lining of your stomach. This reduction in protective prostaglandins leaves the GI lining vulnerable to damage from its own acid, leading to erosions, ulcers, and potentially life-threatening bleeding.

The speed at which this can happen is alarming. One study conducted in healthy volunteers taking 800 mg of ibuprofen three times a day found that evidence of GI bleeding could occur within just three to five days. This drives home the point that even short-term, high-dose use of what many consider a harmless drug (“it’s just Advil”) carries real risk.

Further points to consider regarding GI safety:

• Low-Dose Aspirin + NSAID: Many Aspirinolder patients are on low-dose aspirin for cardiovascular protection. Adding a traditional NSAID to this regimen doubles the risk of a major GI bleed.
• Celecoxib’s GI Advantage: Because celecoxib selectively inhibits the COX-2 enzyme (which is more involved in inflammation) while largely sparing the COX-1 enzyme (more involved in gastric protection), it has a significantly lower risk of GI side effects. Even in studies comparing celecoxib to a combination of a traditional NSAID (like diclofenac or naproxen) plus a proton-pump inhibitor (PPI), celecoxib still demonstrated a better GI safety profile.
• The Limits of PPIs: PPIs (like omeprazole or pantoprazole) primarily protect against stomach ulceration. They do not offer the same protection for the small intestine, where NSAID-induced damage can also occur.

The Underappreciated Cardiovascular Risks of NSAIDs

While the GI risks of NSAIDs are relatively well-known, the cardiovascular risks are often overlooked, especially with over-the-counter use. A black box warning from the FDA highlights that all NSAIDs (except aspirin) carry an increased risk of heart attack and stroke.

Let’s look at some specific, concerning findings from research:

• Post-Myocardial Infarction (MI): In patients who have already had a heart attack, adding an NSAID to their regimen was found to double the risk of a subsequent bleed. This increased risk was seen in as little as three days of NSAID use. This presents a huge clinical dilemma, as many post-MI patients have debilitating arthritis and may be self-medicating for pain, especially if they are trying to avoid opioids.
• Risk in Healthy Individuals with Respiratory Infections: This finding is particularly startling. In a study of patients with no prior history of heart disease, taking an oral NSAID during a respiratory infection (like the flu or a bad cold) was associated with a three-fold increased risk of having a heart attack. Think about how common this scenario is: someone feels sick, achy, and feverish, and their first instinct is to reach for ibuprofen or naproxen. This data suggests that this seemingly benign act carries a significant, albeit temporary, cardiovascular risk.
• Celecoxib and Cardiovascular Risk: While celecoxib is safer for the gut, it does not offer any cardiovascular benefit over other NSAIDs. The risk of heart attack and stroke is considered comparable across the entire class of non-aspirin NSAIDs.

As a clinician, I am very cautious with NSAIDs. I weigh the risks and benefits carefully for each patient. That said, they have their place. In my practice here in the El Paso region, I find them particularly effective for patients experiencing weather-related pain flares. The barometric pressure changes that come with storms can cause significant increases in joint pain and stiffness, and a short course of an anti-inflammatory can be extremely helpful in these situations.

A Glimpse into the Variety of NSAIDs

Many people are only familiar with ibuprofen and naproxen, but there is a wide array of NSAIDs available, each belonging to a different chemical subclass. You don’t need to memorize every single one, but it’s helpful to be aware of the variety. If a patient doesn’t respond to meloxicam (a drug I frequently use), I might select a drug from a different category, like a proprionic acid derivative (naproxen) or an acetic acid derivative (diclofenac), for our next trial. Having this knowledge allows for more strategic and rational prescribing.

Chemical Subclass	Examples
Proprionic Acid Derivatives	Ibuprofen (Advil, Motrin), Naproxen (Aleve, Naprosyn), Ketoprofen
Acetic Acid Derivatives	Diclofenac (Voltaren), Indomethacin (Indocin), Etodolac
Oxicam Derivatives	Meloxicam (Mobic), Piroxicam (Feldene)
Fenamate Derivatives	Meclofenamate, Mefenamic Acid (Ponstel)
COX-2 Selective Inhibitors	Celecoxib (Celebrex)
Salicylates	Aspirin, Salsalate
Other	Nabumetone (Relafen)
This table serves as a good visual reminder of the options available to us when one agent fails. The key is a systematic approach rather than random trial and error.

Topical Agents: Localized Relief with a Systemic Perspective

We’ve discussed oral medications that have systemic effects. Now, let’s shift our focus to topical agents, which are designed to deliver medication directly to the site of pain. This approach is appealing because it promises to concentrate the drug where it’s needed most, theoretically minimizing systemic absorption and side effects.

This is an area of particular interest in my integrative practice. Chiropractic care is excellent at addressing the structural and biomechanical sources of pain. However, concurrent soft tissue inflammation and localized nerve irritation often need additional, targeted support. Topical agents can be a perfect adjunct, providing relief to inflamed muscles or joints while we work on correcting the underlying spinal or extremity dysfunction. They allow us to bridge the gap, managing symptoms locally while the deeper healing process takes place. The use of these agents fits perfectly within our philosophy of using the least invasive, most targeted interventions first.

Diclofenac and Topical NSAIDs: Blocking Prostaglandins with Local Precision

Topical diclofenac (gel, solution, patch) is a cornerstone for localized musculoskeletal pain. What I tell patients is that diclofenac inhibits cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis. Prostaglandins sensitize nociceptors to other stimuli; decreasing them reduces peripheral activation. Studies show topical diclofenac used consistently for a week can provide pain relief comparable to oral NSAIDs, with fewer gastrointestinal and cardiovascular adverse effects due to lower systemic absorption. The American College of Rheumatology strongly recommends topical NSAIDs, especially for older adults with osteoarthritis who may not be candidates for joint replacement; these agents can be excellent for hand OA and other small joints.

Forms and practical usage:

• Diclofenac gel (e.g., Voltaren, generic): Commonly used for hands, knees, and small joints. A typical regimen for hands is 2 grams applied four times daily.
• Topical solution (e.g., Pennsaid): Contains DMSO to enhance penetration; useful when deeper soft tissue access is desired.
• Diclofenac patch (e.g., Flector): Indicated for acute pain due to minor strains, sprains, and contusions—often valuable in acute low back strain episodes.

Clinically, I advise patients to keep one tube by the bathroom and one by the kitchen sink to enhance adherence. We use patches for focal acute strains when patients “throw out their back” or sustain contusions with localized inflammation. This pairs well with integrative chiropractic: adjustments and soft tissue care reduce aberrant load while diclofenac dampens local inflammation.

Topical Anesthetics: Lidocaine Patches and Local Sodium Channel Modulation

For neuropathic pain localized to a dermatomal band or focal area, topical anesthetics are essential tools. Nociceptors convey signals partly through voltage-gated sodium channels. Lidocaine stabilizes neuronal membranes by inhibiting these channels, reducing abnormal firing. In postherpetic neuralgia (PHN), lidocaine patches have demonstrated significant early benefits: approximately 65% improvement in pain and 77% improvement in quality of life by week one in selected studies. Standard use is 12 hours on, 12 hours off to avoid skin irritation. Systemic toxicity is rare, highlighting a wide safety margin. For PHN along the chest wall or waist, patches can enable sleep and daily function. In focal radicular pain, patches can reduce allodynia over the involved dermatome while we address the root cause with chiropractic and rehab.

Capsaicin and TRPV1 Desensitization: Over-The-Counter and In-Office Qutenza

Capsaicin acts at the TRPV1 receptor (a heat-activated calcium channel) on nociceptors. Chronic stimulation with capsaicin leads to desensitization and reduced substance P signaling. Lower-concentration creams can be applied at home; initial burning is common but typically diminishes. In-office Qutenza (8% capsaicin patch) is applied every three months for 30–60 minutes under supervision. Evidence supports its use in diabetic peripheral neuropathy and postherpetic neuralgia. We often pair capsaicin therapy with chiropractic strategies that enhance nerve root mechanics and segmental motion.

Off-Label Topicals: Clonidine Gel and Magic Mouthwash

Off-label compounds can serve as adjuncts. Clonidine gel, an alpha-2 adrenergic agonist, may modulate sympathetically mediated pain in complex regional pain syndrome (CRPS). Magic mouthwash, a compounded formulation with a local anesthetic and other agents, is used in oncology for oral mucositis and can be adapted for burning mouth syndrome to reduce local nociception.

Balancing Body and Metabolism- Video

Anti-Seizure Medications in Pain Management: A Closer Look

Let’s spend a moment on a class of drugs frequently used for neuropathic pain: anticonvulsants, or anti-seizure medications. We’ve already touched upon gabapentin and pregabalin (Lyrica), which remain our most evidence-backed options in this category for managing various pain conditions. Their mechanism, which involves modulating calcium channels to calm overexcited nerves, has proven effective in numerous clinical trials for conditions like diabetic neuropathy, postherpetic neuralgia, and fibromyalgia.

However, it’s equally important to understand which medications in this class are not effective for generalized chronic pain. This helps us avoid prescribing ineffective treatments and guides our clinical decisions toward what actually works.

• Lamotrigine (Lamictal): This is a key point to emphasize. Despite being an effective anticonvulsant and mood stabilizer, lamotrigine has zero—none—evidence for efficacy in chronic pain. This isn’t an opinion; it’s a conclusion drawn from rigorous scientific study. It simply does not provide a meaningful analgesic effect for the types of pain we commonly treat, such as neuropathic or musculoskeletal pain. Therefore, it has no place in our pain management toolkit for these conditions.
• Topiramate (Topamax): This is another medication that is often misused in the context of general pain. While topiramate is a valuable tool, its indication is highly specific. The primary, evidence-based use for topiramate in the realm of pain is for migraine prophylaxis. It helps reduce the frequency and severity of migraine headaches. Unfortunately, I’ve seen it prescribed for other pain conditions like shingles pain, complex regional pain syndrome (CRPS), or radicular pain stemming from a herniated disc. For these conditions, topiramate is not the answer. The evidence does not support its use, and we would be exposing the patient to potential side effects without a reasonable expectation of benefit.

My goal in this discussion is to equip both clinicians and patients with the clarity needed to make informed decisions. When it comes to anti-seizure medications for pain, we must be precise and evidence-driven. We stick to what the research supports, which primarily points us back to gabapentin and pregabalin.

Neuropathic Agents as Membrane Stabilizers: Gabapentin and Pregabalin Deep Dive

Neuropathic agents are often misunderstood. I teach patients that these do not merely dull pain; they change nerve excitability by modulating presynaptic calcium channel activity, reducing the release of excitatory neurotransmitters, and stabilizing neuronal membranes.

Gabapentin: Mechanism, Dosing Principles, and Clinical Nuance

Gabapentin binds the alpha-2-delta subunit of voltage-gated calcium channels in presynaptic neurons, reducing release of excitatory neurotransmitters like glutamate and substance P. This slows the transmission of pain signals. Renal dosing is necessary, and bioavailability declines as the dose increases due to saturable transport. I always start low and titrate slowly (e.g., 100-300 mg at night, then gradually increase) to protect a patient’s options and avoid side effects like dizziness or somnolence that might cause them to reject the medication prematurely.

Pregabalin: Mechanism, Dosing, Risks, and Clinical Application

Pregabalin (Lyrica) works similarly on the alpha-2-delta subunit but has more predictable pharmacokinetics. The typical max dose is 600 mg daily, but many patients experience diminishing returns beyond 450 mg/day with disproportionate side effects. We start at 25-50 mg twice daily and titrate every few days, monitoring for dizziness, somnolence, edema, and weight changes. Recent studies have suggested a potential increased risk of adverse cardiovascular outcomes in some populations, so medical oversight from Dr. Cardenas is key, especially for patients with existing cardiovascular disease.

Antidepressants for Pain: More Than Just “In Your Head”

One of the most significant and often misunderstood areas of pain management is the use of antidepressants. When we suggest an antidepressant for chronic pain, patients often feel their physical experience is being dismissed as a psychological problem. We must clarify that this is absolutely not what we are saying.

The use of certain antidepressants for pain is rooted in solid neurophysiology. Our brain has its own powerful, built-in system to protect us from being overwhelmed by pain, known as the descending modulation pathway. This pathway originates in the brainstem and travels down the spinal cord, acting like a braking system by releasing neurotransmitters that “tamp down” the intensity of incoming pain signals. Two of the most important neurotransmitters in this protective system are serotonin and, critically, norepinephrine.

The antidepressants we use for pain, particularly the serotonin-norepinephrine reuptake inhibitors (SNRIs) and tricyclic antidepressants (TCAs), work by increasing the availability of these specific neurotransmitters. By boosting norepinephrine and serotonin levels, these medications effectively amplify the brain’s natural ability to block pain signals.

Key points for patients:

• These are real pain medications with studies conducted on patients without mood disorders.
• They are typically taken once a day and are non-addictive.
• They work in the absence of a mood disorder. The pain-relieving effect is separate from any antidepressant effect.

For example, when the clinical trials for duloxetine (Cymbalta) were conducted, researchers intentionally excluded individuals with major depressive disorder to ensure that the observed pain relief was a direct result of the drug’s effect on pain pathways. The results were clear: it works directly on pain.

The Black Box Warning for Antidepressants: An Essential Conversation

Before prescribing any antidepressant, we have a responsibility to address the FDA’s black box warning. This warning was issued in 2004 in response to data showing an increased risk of suicidal thoughts and behaviors in children and adolescents taking SSRIs.

The conversation I have with my adult patients takes about 90 seconds and covers these essential points:

• The Risk is Age-Specific: The original data showed the risk primarily in children and adolescents. In clinical trials involving patients above the age of 24, there was no statistically significant increased risk of suicidality.
• The Highest Risk Group: The group with the most significant risk was young men between 18 and 25. The theory is that the antidepressant can increase motivation and energy before it improves mood, potentially giving a person with underlying suicidal thoughts the capacity to act on them.
• A Protective Effect in Older Adults: In adults age 65 and over, antidepressants have a protective effect against suicidality.

Having this quick, transparent conversation educates the patient, demystifies the warning label, and solidifies the therapeutic alliance.

Understanding Serotonin Syndrome: A Rare but Serious Condition

Whenever we discuss medications that affect serotonin, the topic of serotonin syndrome comes up. It’s important to have a balanced perspective. It is rare and has a very specific clinical presentation.

• Rapid Onset: Symptoms typically develop very quickly, with 60% of patients developing them within six hours of starting or increasing a serotonergic drug.
• Clinical Presentation: The hallmark is a triad of symptoms:

1. 1. Mental Status Changes: Agitation, confusion.
   2. Autonomic Instability: Fever, sweating, rapid heart rate.
   3. Neuromuscular Hyperactivity: Tremor, muscle rigidity, and most distinctively, clonus and hyperreflexia.

The Hunter Criteria are the gold standard for diagnosis and heavily rely on the presence of clonus (rhythmic, involuntary muscle contractions) or hyperreflexia. If a patient is concerned, a quick neuromuscular exam can often rule it out, allowing us to reassure them and address other potential causes of their symptoms.

Duloxetine (Cymbalta): A Versatile Tool for Chronic Musculoskeletal Pain

Let’s dive deeper into duloxetine (Cymbalta). It is FDA-indicated not only for neuropathic pain and fibromyalgia but also for chronic musculoskeletal pain, which includes conditions like chronic low back pain or osteoarthritis (OA) of the knee. Its ability to enhance the descending pain-inhibiting pathways makes it a powerful alternative or adjunct to NSAIDs, especially for older patients with comorbidities.

• Expected Outcome: A good rule of thumb is that about 50% of people will experience about 50% improvement in their pain.
• Dosing Strategy: We start at 30 mg daily for one week to minimize nausea, then increase to the target dose of 60 mg once daily. I often proactively prescribe an anti-nausea medication like ondansetron (Zofran) to help patients get through the initial period.

Other SNRI Options: Milnacipran and Venlafaxine

• Milnacipran (Savella): Its only FDA-approved indication is for fibromyalgia. It has the highest affinity for norepinephrine reuptake inhibition, which can cause more side effects like agitation and increased heart rate.
• Venlafaxine (Effexor): There is some evidence for its use in painful diabetic neuropathy, but it is not as robust as for duloxetine. I would not choose it as a first-line agent for pain.

Tricyclic Antidepressants (TCAs): The Old School Powerhouses

While largely replaced for depression, tricyclic antidepressants (TCAs) like amitriptyline and nortriptyline remain incredibly effective for chronic pain. However, they require careful management due to anticholinergic side effects (constipation, dry mouth, cognitive fog) and cardiac risks at high doses.

Crucially, the doses used for pain are much lower than those for depression.

• Pain Dosing: 10 mg – 75 mg daily (commonly 10 mg – 50 mg)
• Depression Dosing: 100 mg – 300 mg daily

We typically start at 10 mg per day at bedtime. It’s important to tell patients that a proper therapeutic trial is six to eight weeks, as the benefit is not immediate.

A Public Service Announcement: Burning Mouth Syndrome

I feel it is my personal duty to spread awareness about Burning Mouth Syndrome (BMS). This is a chronic, debilitating condition of a burning sensation in the mouth without any visible signs of irritation. It typically affects women in their perimenopausal or postmenopausal years. For this specific condition, the tricyclic antidepressants seem to work best. My typical protocol is to start with 10 mg of nortriptyline at bedtime, titrating up weekly to a maximum of 50 mg. Often, patients find significant relief at low doses. Recognizing this underdiagnosed condition and offering an effective treatment can be truly life-changing.

A Critical Look at Muscle Relaxants for Pain

The intuitive logic for using muscle relaxants for acute low back pain and sciatica seems sound, but the clinical evidence is less impressive. For sciatica, we find a conspicuous lack of significant benefit. For acute low back pain, some studies show a modest, short-term benefit for about one week, but this effect is largely confined to the back itself with no improvement in leg pain.

Most muscle relaxants do not target the muscle directly; their primary mechanism is global depression of the central nervous system (CNS).

• Diazepam (Valium): This benzodiazepine is not superior to other muscle relaxants and carries all the risks of its class, including dependence and dangerous interactions with opioids.
• Cyclobenzaprine (Flexeril): This drug is chemically similar to tricyclic antidepressants (TCAs). This can be risky for patients with mood disorders, especially bipolar disorder, as it can trigger mania. It also has a long half-life and accumulates in the body, leading to significant sedation and cognitive impairment within a few days.
• Tizanidine (Zanaflex): As a central alpha-2 adrenergic agonist, it is effective for spasticity (from conditions like MS) rather than simple muscle spasm. Its very short duration of therapeutic effect is a clinical advantage, giving the patient control to use it on-demand without prolonged sedation.
• Carisoprodol (Soma): This is a Schedule IV controlled substance due to its high potential for abuse. It is metabolized into a barbiturate-like substance and is rarely a first-line choice.
• Baclofen (Lioresal): This is also indicated for muscle spasticity. It works on GABA-B receptors. Abrupt withdrawal can be life-threatening, causing seizures and hallucinations. It can also cause hyperglycemia and lower the seizure threshold.

In our integrative practice, we prefer hands-on therapies like chiropractic adjustments and soft tissue mobilization to address the root cause of muscle spasm without the systemic risks of CNS depressants.

The Perils of Polypharmacy: Benzodiazepines and Opioids

A common, yet perilous, combination of medications is the concurrent use of opioids and benzodiazepines.

Let’s be unequivocally clear: Benzodiazepines are not pain medications. They have no primary analgesic properties. Research shows they can act as antagonists to opioid analgesia, meaning they can actively prevent opioids from working effectively. This can lead to a dangerous cycle where patients request higher opioid doses, increasing the risk of respiratory depression and overdose. The statistics are alarming: patients on high-dose opioids who also take benzodiazepines have an overdose rate that is ten times higher.

The Critical Need for Appropriate Anxiety Treatment

Despite these dangers, we should never avoid the appropriate medical treatment of anxiety simply because a patient is also being treated for pain. It is our responsibility to serve our patients with comorbidities. Forcing a patient to choose between treating their debilitating pain or their crippling anxiety is a false and harmful dichotomy. The goal is to build a comprehensive, individualized treatment plan that safely addresses all facets of a patient’s health, integrating non-pharmacological interventions like chiropractic care, cognitive-behavioral therapy (CBT), and mindfulness meditation whenever possible.

Low-Dose Naltrexone (LDN): A Paradigm Shift in Chronic Pain Treatment

One of the most exciting tools in modern pain management is Low-Dose Naltrexone (LDN). While the standard 50 mg dose is an opioid antagonist used in addiction medicine, at a low dose of 1.5 to 4.5 milligrams, it has a different set of effects.

The key mechanism is believed to be the modulation of glial cells, the immune cells of the CNS. In chronic pain states, glial cells become activated and release inflammatory mediators, a process called neuroinflammation. LDN appears to calm these glial cells, down-regulating their inflammatory response and dampening central sensitization. It is also thought to cause a rebound increase in the body’s own endorphins.

Clinical Applications and Evidence for LDN

The evidence base for LDN is growing, with promising results in:

• Fibromyalgia: This is perhaps the best-studied indication for LDN.
• Long COVID: Researchers are actively exploring LDN to modulate the sustained immune response.
• Autoimmune Conditions: It has shown promise in conditions like Ehlers-Danlos Syndrome (EDS) and Crohn’s disease, where studies have shown no evidence of healing of the colon lining.

LDN must be prepared by a compounding pharmacy. The typical starting dose is 1.5 milligrams per day at bedtime, titrating slowly up to a target of 4.5 milligrams per day. It is a powerful tool that, when combined with chiropractic care to reduce nerve irritation, can offer a synergistic approach to breaking the cycle of chronic pain.

Suzatrigine: The New Kid on the Block for Acute Pain

Approved in February 2025, suzatrigine is a novel non-opioid for managing acute pain. It is a selective inhibitor of a specific sodium channel known as Nav1.8, which is found predominantly on pain-sensing neurons. By blocking this channel, it prevents the pain signal from being generated at the source.

• Indication and Dosing: Indicated only for acute pain as a two-week course. It begins with a 100-milligram loading dose, followed by 50 milligrams twice a day.
• Efficacy: Clinical trials showed it was almost equal in analgesic effect to 5 mg of hydrocodone twice a day, without the risks of opioids.
• Important Considerations: Insurance authorization can be a hurdle. Critically, it can affect the metabolism of some oral contraceptives, so patients must be counseled to use an alternative form of contraception during and for one month after treatment.

Understanding the Role of Opioids: Real-World Patient Scenarios

Despite the public health crisis, opioids remain a necessary tool for a specific subset of patients with severe, intractable pain who have exhausted all other reasonable treatment options. Consider these real patient scenarios from my practice:

• Patient Case 1: Mike: A 56-year-old construction worker with lumbar bulging discs and severe facet arthropathy. He cannot take NSAIDs due to a history of a myocardial infarction and being on anticoagulants. He has failed other therapies. For him, opioids are what allow him to continue working and providing for his family.
• Patient Case 2: Sheila: An 84-year-old woman with a failed L4-S1 fusion, severe adjacent segment disease, and terrible bone density, making her a non-surgical candidate. A spinal cord stimulator helps her leg pain but not her axial low back pain. For her, opioids allow her to have a reasonable quality of life.

These are not “drug seekers.” They are regular people with legitimate pathology who have failed all other appropriate treatment avenues.

The Mechanism and Management of Opioid Therapy

Opioids work on mu, delta, and kappa receptors in the central and peripheral nervous system. Their activation of mu receptors in the GI system is why opioid-induced constipation is so common. To prescribe them responsibly, I follow a strict checklist:

1. Comprehensive Physical Exam
2. Risk Assessment (e.g., SOAP-R or COMM tool)
3. Rule Out Fixable Causes
4. Medication Agreement (Pain Contract)
5. Prescription Drug Monitoring Program (PDMP) Review before every script.
6. Document Everything: Meticulously document what treatments the patient has tried and failed and why they cannot try

Navigating Opioid Selection: A Quick Guide

Here is a simplified list of common opioids by DEA schedule:

• Schedule IV: Tramadol
• Schedule III: Buprenorphine (Butrans, Belbuca), Codeine/Acetaminophen
• Schedule II (Short-Acting): Hydrocodone, Oxycodone, Hydromorphone, Morphine, etc.
• Schedule II (Long-Acting): Fentanyl Patch, OxyContin, MS Contin, Methadone, etc.

Our arsenal of unique opioid molecules is quite limited. The key to choosing the right one often lies in understanding individual patient metabolism.

The Cytochrome P450 System and Personalized Opioid Selection

Why does one patient get relief from one Percocet while another feels nothing from five? The answer is often genetics, specifically in the Cytochrome P450 (CYP450) enzyme system. Genetic variations can cause these liver enzymes to work at different speeds.

• Poor Metabolizers: Have slow enzymes, causing drugs to accumulate and lead to exaggerated effects from a standard dose.
• Rapid Metabolizers: Have hyperactive enzymes that clear drugs so quickly they don’t have time to work. These patients are not “drug-seeking”; their body is literally “speeding right through” the medication.

Many opioids like hydrocodone, oxycodone, and tramadol rely on the CYP450 system. In contrast, morphine, hydromorphone (Dilaudid), and oxymorphone (Opana) are metabolized through a different process.

This has profound clinical implications. If a patient reports that oxycodone does nothing for them, it could be a clue that they are a rapid metabolizer. Instead of escalating the dose, it makes more sense to switch to a drug from a different metabolic class. This is why equianalgesic dosing charts must be used as a rough guide, with titration always based on the individual patient’s response.

Spotlight on Specific Opioids: Buprenorphine and Methadone

• Buprenorphine for Pain: Formulations like the Butrans patch and Belbuca buccal films are excellent options for chronic pain. As a partial mu-agonist, it has a ceiling effect on respiratory depression, making it significantly safer. The once-a-week Butrans patch is fantastic forelderly, cognitivelyy impaired patients. It is no longer recommended to stop buprenorphine prior to surgery.
• Methadone: Use with Extreme Caution: My advice is simple: If you are not an expert in using it, do not use it. Its elimination half-life (8-59+ hours) is much longer than its analgesic effect (4-8 hours), creating a high risk of drug accumulation and unexpected overdose. It also causes QT prolongation and has a complex, non-linear conversion from other opioids.

Safe Storage, Disposal, and the Management of Opioid Side Effects

Safe Storage and Disposal of Opioids

Research shows about 72% of patients have leftover opioids after surgery, and most keep them. These unsecured pills are a primary source of diversion. The FDA’s guidance, if take-back sites are not available, is to flush them down the toilet due to the extreme danger of accidental ingestion.

Managing Opioid-Induced Constipation (OIC)

OIC is the most common and persistent side effect. Do not tell patients on opioids to take bulk-forming agents like Metamucil. Adding bulk to a stagnant system is like adding more cars to a traffic jam. We have a class of drugs called PAMORAs (Peripherally Acting Mu-Opioid Receptor Antagonists) like Relistor and Movantik. These brilliant drugs block opioid receptors in the gut without crossing the blood-brain barrier, reversing constipation without affecting pain relief.

Naloxone (Narcan): An Essential Safety Tool

Naloxone (Narcan) is an opioid antagonist that can rapidly reverse an overdose. I believe co-prescribing naloxone; I frame it as being for a risky drug, not a risky patient. Writing a prescription for naloxone has been shown to decrease the overall overdose rate in that patient population. It is vital to educate patients and caregivers that you cannot hurt someone by giving them naloxone if you suspect an overdose.

Final Thoughts: The Art and Science of Pain Management

1. Our Options are Limited, So Creativity is Key: We may need to try novel combinations or revisit medications a patient tried years ago.
2. Dosing Strategy Matters as Much as Drug Choice: Simply shifting the timing of a dose can make a world of difference.
3. Medications are Only One Component of Care: True healing comes from a comprehensive approach that includes chiropractic care, physical rehabilitation, nutritional therapy, and addressing the patient as a whole person. This is what we strive to provide at Injury Medical Clinic.

Let’s Connect

I would love to connect with all of you. It is easiest to reach me via email or through my LinkedIn profile. Thank you for joining me for this educational discussion.

• LinkedIn: Alex Jimenez on LinkedIn
• Practice Website & Blog: Wellness Doctor RX

Take care.

References

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• Argoff, C. E. (2020). Methadone for chronic pain. Pain Management Nursing, 21(6), 507-511.
• Bernard, S. A., & O’Connell, T. (2020). Cytochrome P450-mediated drug-drug interactions in pain management. Journal of the American Association of Nurse Practitioners, 32(12), 859-868.
• Centers for Disease Control and Prevention. (2022). CDC Clinical Practice Guideline for Prescribing Opioids for Pain — United States, 2022. MMWR Recommendations and Reports, 71(No. RR-3), 1–95.
• Chapman, E. J., & Ruan, X. (2022). Buprenorphine for chronic pain: A review of the clinical evidence. Current Pain and Headache Reports, 26(7), 543-550.
• Finnerup, N. B., Attal, N., Haroutounian, S., McNicol, E., Baron, R., Dworkin, R. H., … & Toth, C. (2015). Pharmacotherapy for neuropathic pain in adults: a systematic review and meta-analysis. The Lancet Neurology, 14(2), 162–173.
• Food and Drug Administration. (2020). Disposal of unused medicines: What you should know.
• Jackson, K. C., & St. Onge, E. L. (2021). Peripherally acting mu-opioid receptor antagonists (PAMORAs) for opioid-induced constipation: A review of the evidence. Journal of Pain and Palliative Care Pharmacotherapy, 35(3), 163-172.
• Jones, M. R., & Viswanath, O. (2023). Benzodiazepine use and misuse. StatPearls. StatPearls Publishing.
• Liang, Y., & Clark, J. D. (2016). The link between glial activation and opioid tolerance. Current Neuropharmacology, 14(1), 60–67.
• Lunn, M. P. T., Hughes, R. A. C., & Wiffen, P. J. (2014). Duloxetine for treating painful neuropathy, chronic pain or fibromyalgia. Cochrane Database of Systematic Reviews, (1).
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• O’Malley, P. G., Balden, E., Tomkins, G., Santoro, J., & Kroenke, K. (2011). Treatment of fibromyalgia with antidepressants: a meta-analysis. Journal of General Internal Medicine, 26(11), 1309–1316.
• org. (n.d.). Naloxone for opioid overdose prevention.
• See, S., & Ginzburg, R. (2008). Choosing a skeletal muscle relaxant. American Family Physician, 78(3), 365-370.
• Shaheen, H. A., Cheiman, R., & De-Allie, C. (2020). Benzodiazepines for low-back pain. Cochrane Database of Systematic Reviews, (11).
• Volpi-Abadie, J., Kaye, A. M., & Kaye, A. D. (2013). Serotonin syndrome. Pain Physician, 16(6), E681–E686.
• Wang, Z. Y., Chen, Z. T., Yang, H. L., & Zhang, Y. (2022). The efficacy and safety of duloxetine for the treatment of knee osteoarthritis: a meta-analysis of randomized controlled trials. BMC Musculoskeletal Disorders, 23(1), 503.
• Younger, J., Parkitny, L., & McLain, D. (2014). The use of low-dose naltrexone (LDN) as a novel anti-inflammatory treatment for chronic pain. Clinical Rheumatology, 33(4), 451–459.

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