Clinical Approach: Key Insights in Pain Pharmacology

Explore the pain pharmacology in a clinical approach to effectively manage pain with targeted treatments and innovative strategies.

Abstract

Welcome to this educational post designed to make the complex world of pain management clear, actionable, and deeply human. I am Dr. Alexander (Alex) Jimenez, DC, APRN, FNP-BC, CFMP, IFMCP, ATN, CCST. Drawing on decades of clinical experience across chiropractic, advanced nursing, functional medicine, rehabilitation, and personal injury care, I present a modern, integrated roadmap for understanding and treating pain from the periphery to the brain.
You will learn:

• How pain arises and persists physiologically, from peripheral sensitization in tissues to central amplification in the spinal cord and brain.
• The latest evidence on acetaminophen, NSAIDs (including GI and cardiovascular risks), topical agents (diclofenac gels/patches, lidocaine patches), capsaicin therapy (including Qutenza 8%), gabapentin and pregabalin, SNRIs (especially duloxetine), and TCAs (e.g., nortriptyline for burning mouth syndrome).
• Why benzodiazepines are not pain medications and how they can antagonize opioid analgesia.
• The role of low-dose naltrexone and emerging non-opioid agents targeting Nav1.8 in acute pain.
• How integrative chiropractic care reduces mechanical drivers and modulates neuroimmune pathways to complement pharmacology.
• Our coordinated, multidisciplinary model at Injury Medical Clinic PA (Mission Plaza Injury Medical Clinic) in El Paso, Texas, led with medical direction from Dr. Maria Guadalupe Cardenas, MD (Board Certified in Internal Medicine; NPI #1164426749; Texas MD License #J2933), who serves as our Medical Director and Collaborative Physician with over four decades of experience.
• Clear patient communication strategies, safety protocols, dosing pearls, and functional medicine supports to address sleep, inflammation, gut-brain dynamics, and resilience.
• Practical case patterns, operational workflows, and documentation strategies for personal injury care and chronic pain.

This guide is grounded in modern, evidence-based research and showcases findings from leading investigators using rigorous methods. My goal is to empower you—with nuanced science that is easy to understand—so you can make informed decisions and see how an integrative team can personalize your path toward meaningful relief and restored function.

Patient-Centered Foundations For Effective Pain Management

Setting Realistic Expectations: Pain Management As A Process

In 25 years of interventional and integrative pain care, I have learned a simple truth: pain management is a process, not a pill. Many patients arrive expecting total relief from a single prescription. When they experience anything less than 100%, they sometimes feel care is being withheld. This mindset can undermine progress.

• Clinically meaningful improvement is commonly defined as a 30–60% reduction in pain.
• By combining therapies, we can stack improvements into meaningful outcomes:
  • 30% from a targeted medication
  • 20% from personalized chiropractic adjustments and rehabilitation
  • 10% from nutrition and anti-inflammatory protocols
  • 25% from sleep optimization and stress regulation

Taken together, these contribute to a transformation in daily function and quality of life. Integrative care is about leveraging multiple mechanisms to achieve cumulative benefit.

Measuring What Matters: Function Over Numbers

The ubiquitous 0–10 pain scale offers a snapshot but lacks context. A “10” while immobilized on the couch is different from a “10” after spending the afternoon walking with your granddaughter. Functional gains are victories.

• Consider standardized tools like the Brief Pain Inventory (BPI), which evaluates interference with mood, mobility, work, relationships, sleep, and enjoyment of life.
• Collaboratively define patient-identified goals:
  • “Sleep through the night.”
  • “Walk the dog around the block without stopping.”
  • “Sit through a recital without frequent position changes.”
  • “Enjoy dinner out without pain dominating the experience.”

These goals shape our plan, track progress, and reinforce shared decision-making and patient agency.

The Team Behind Integrative Care In El Paso, Texas

Our Multidisciplinary Model: Internal Medicine Meets Chiropractic

At Injury Medical Clinic PA (also known as Mission Plaza Injury Medical Clinic) in El Paso, Texas, we operate a multidisciplinary integrative care model common in personal injury and comprehensive pain settings.

• Medical direction and oversight are provided by Dr. Maria Guadalupe Cardenas, MD (Board Certified in Internal Medicine; NPI #1164426749; Texas MD License #J2933), our Medical Director and Collaborative Physician with over 40 years of internal medicine experience.
• I, Dr. Alexander Jimenez, DC, APRN, FNP-BC, CFMP, IFMCP, ATN, CCST, integrate chiropractic, functional medicine, rehabilitation, movement therapy, and pharmacologic stewardship.

This co-managed approach ensures:

• Comprehensive diagnostic stewardship, comorbidity management, and risk stratification.
• Seamless integration of manual therapies, movement retraining, nutrition and metabolic supports, and medication protocols.
• Coordinated personal injury documentation, rehabilitation programming, and referral pathways.

How We Integrate Care Day-To-Day

• Chiropractic evaluation and corrective care: Spinal and peripheral joint assessment, targeted adjustments, soft-tissue mobilization, neurodynamic techniques, and posture/ergonomics.
• Internal medicine oversight: Diagnostic workups, cardiometabolic risk management, medication safety, polypharmacy reconciliation, and interventional referrals.
• Functional medicine: Anti-inflammatory nutrition plans, gut-brain axis modulation, micronutrient optimization, sleep support, and stress resilience.
• Personal injury and rehabilitation: Graded exposure, sensorimotor retraining, strengthening and flexibility, return-to-function programs, and reporting for insurers/legal stakeholders.

This structure allows us to choose the right intervention for the right mechanism at the right time, while monitoring risk and outcomes precisely.

Understanding Pain Physiology: From Periphery To Brain

Peripheral Sensitization: The Chemical Cascade We Can Modulate

When tissue is injured, the local microenvironment explodes with pro-inflammatory mediators:

• Prostaglandins amplify nociceptor sensitivity and facilitate bradykinin actions.
• Histamine, serotonin (5-HT), bradykinin, CGRP, and substance P further sensitize the peripheral nerve endings and drive vasodilation, neurogenic inflammation, and swelling.
• Ion channels, including sodium, calcium, and TRPV1, open, lowering firing thresholds and increasing pain signal frequency.

These signals travel from the periphery through the dorsal root ganglion (DRG) into the spinal cord dorsal horn. Modulating this peripheral chemistry with topical agents and anti-inflammatories can reduce the signal before it reaches and amplifies centrally.

Central Sensitization: Hyperexcitability In The Spinal Cord And Brain

Sustained peripheral input induces central sensitization, where dorsal horn neurons become hyperresponsive (allodynia, hyperalgesia). Altered neurotransmission (glutamate, substance P) and microglial activation amplify ascending pain signals. Descending inhibitory pathways—powered by norepinephrine and serotonin—may be compromised.

• Descending pain modulation system (DPMS): PAG → RVM → dorsal horn, with contributions from the locus coeruleus (norepinephrine) and raphe nuclei (serotonin).
• Antidepressants like SNRIs and TCAs enhance descending inhibition by increasing monoamine availability in the dorsal horn, reducing painful input transmission.

Integrating chiropractic care—to reduce mechanical drivers—and pharmacology—to quiet peripheral and central amplification—produces synergistic relief.

Over-The-Counter Cornerstones: Acetaminophen And NSAIDs

Acetaminophen: Deceptively Simple And Widely Misunderstood

We have used acetaminophen for decades, yet its precise mechanism of action remains incompletely defined. It appears to act centrally, possibly via a COX variant (COX-3) and interactions with the endocannabinoid system.

• Safety limit: Adults should not exceed 4 grams per day.
• Hidden risk: Acetaminophen appears in hundreds of OTC and prescription products, making unintentional overdose common.
  • Approximately 30,000 hospitalizations yearly in the U.S. are for hepatotoxicity.
  • About 50% of overdoses are unintentional due to product stacking.

Education initiatives like “Know Your Dose” help patients track total intake. Clinically, acetaminophen’s efficacy for chronic low back pain is often similar to placebo in trials; however, individual responses vary. In patients without contraindications, a scheduled regimen can serve as a low-risk foundational layer, often safer than NSAIDs for those with GI or cardiovascular risk.

• Reference: Gerriets, Anderson, & Nappe, 2023, Acetaminophen

NSAIDs: Potent Relief With Systemic GI And Cardiovascular Risks

NSAIDs inhibit cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis. They deliver powerful anti-inflammatory relief but carry substantive risks:

• No single NSAID is universally superior for efficacy; responses are individual.
• A true trial requires consistent dosing for at least four days at therapeutic levels.
• If one class fails or causes side effects, switch classes (propionic acids, acetic acids, enolic acids, COX-2 selective, fenamates).

Key GI insights:

• GI damage from NSAIDs is systemic, not just local mucosal contact. By reducing protective gastric prostaglandins, NSAIDs weaken the mucosal barrier.
• Significant GI bleeding can occur within 3–5 days on high-dose ibuprofen regimens in healthy volunteers.
• PPIs mainly protect the stomach, not the small intestine, leaving risk for NSAID enteropathy.
• Celecoxib spares COX-1 and demonstrates lower GI risk, sometimes outperforming traditional NSAID + PPI combinations.
• Combining aspirin with traditional NSAIDs can double the risk of major GI bleed.

Cardiovascular risks:

• Except for aspirin, all NSAIDs carry increased heart attack and stroke risk.
• Risk appears early—even within three days—especially in post-MI patients.
• Short-term oral NSAID use for respiratory infections is associated with a threefold increased MI risk in otherwise healthy individuals.
• Celecoxib does not offer a CV advantage over traditional NSAIDs.

Given these data, NSAIDs require individualized risk stratification and diligent monitoring. Topical-first strategies can mitigate systemic risks.

• References: Bally et al., 2017; Lanza, Chan, & Quigley, 2009; Bindu, Mazumder, & Bandyopadhyay, 2020

Topical Therapies: Local Action, Lower Systemic Exposure

Topical Diclofenac: Targeted Anti-Inflammatory Relief

Why topical anti-inflammatories matter:

• Reduce local prostaglandin-driven sensitization at the source.
• Minimize systemic GI and CV risks compared to oral NSAIDs.
• Evidence shows comparable analgesia to oral NSAIDs for certain conditions with improved safety.

Forms and practical use:

• Diclofenac gel (OTC Voltaren and generics): Hands often at 2 grams, four times daily.
• Diclofenac solution (e.g., Pennsaid): Includes DMSO for enhanced dermal absorption.
• Diclofenac patches (e.g., Flector): For acute strains, sprains, contusions; useful in acute low back pain.

Mechanism:

• Inhibits COX and prostaglandin synthesis, reducing bradykinin facilitation and nociceptor sensitization.

Coaching for adherence:

• Keep accessible tubes in frequently used locations.
• Note absorption timing: active diclofenac is largely absorbed within ~20 minutes.

Special populations:

• The American College of Rheumatology encourages topical-first approaches, particularly in patients over 75, where oral NSAIDs present higher risk.

Integrative chiropractic alignment:

• Combine topical diclofenac with:
• Joint mobilization and alignment correction to reduce mechanical loading.
• Soft-tissue release to optimize microcirculation and reduce periarticular tension.
• Therapeutic exercises for grip strength, wrist stability, and tendon gliding.

Dr. Cardenas ensures renal and cardiovascular risk management alongside topical-first strategies.

• References: Atchison & O’Connor, 2013; Gatti et al., 2011

Lidocaine Patches: Stabilizing Peripheral Sodium Channels

Clinical impact:

• In postherpetic neuralgia (PHN), lidocaine patches can yield ~65% pain improvement and ~77% quality-of-life improvement by week one.

Mechanism:

• Blocks voltage-gated sodium channels in peripheral nociceptors, suppressing ectopic discharges that drive neuropathic pain.

Safety and dosing:

• Use 12 hours on, 12 hours off.
• Minimal systemic absorption; favorable safety even in broader applications.

Integrative pairing:

• Combine with neurodynamic mobilization, postural correction, and stabilization exercises.
• Functional supports may include alpha-lipoic acid, B vitamins, and omega-3s.

Capsaicin Therapy: TRPV1 Activation Followed By Desensitization

OTC and prescription:

• OTC capsaicin creams for localized neuropathic pain.
• Qutenza (8% capsaicin patch): Office-applied therapy for PHN and diabetic peripheral neuropathy every three months for 30–60 minutes per session.

Mechanism:

• Activates TRPV1 (heat-activated calcium channels) on nociceptors.
• Prolonged activation induces desensitization and reduces substance P stores.

Clinical notes:

• May require 2–3 applications over 6–9 months.
• Ideal for well-localized cutaneous neuropathic pain with systemic contraindications.

Compounded topicals for select cases:

• Clonidine gel (alpha-2 agonist): Consider in CRPS to modulate sympathetic-mediated pain.
• Magic mouthwash: For mucositis or burning mouth symptoms; blends anesthetic, antacid, antihistamine, and antifungal when needed.

These topical strategies are invaluable when systemic exposure must be minimized.

• References: Qutenza Prescribing Information, Topical lidocaine evidence

Neuropathic “Membrane Stabilizers”: Gabapentin And Pregabalin

Gabapentin: Alpha-2-Delta Modulation And Neuroglial Effects

Mechanism in plain language:

• Gabapentin binds the alpha-2-delta subunit of voltage-gated calcium channels, reducing presynaptic release of excitatory neurotransmitters (e.g., glutamate).
• Think of an overexcited relay race: gabapentin slows the handoffs, calming hyperexcitability.

Emerging insights:

• Potential interactions with glial cells contributing to neuroinflammation.
• May modulate overall serotonin levels without acting on serotonin receptors directly.

Indications and dosing:

• FDA-approved for postherpetic neuralgia; widely used for radicular pain, fibromyalgia, peripheral neuropathy, and central sensitization.
• Start low and go slow (e.g., 100–300 mg at night), titrate cautiously, adjust for renal function.
• Remember nonlinear absorption: bioavailability declines as dose increases; more isn’t always more effective.

Safety pearls:

• Rare but serious DRESS syndrome: monitor rash, fever, multisystem involvement—stop and refer urgently.
• Screen for sleep-related breathing concerns, including central sleep apnea in at-risk patients.
• Capsules may use gelatin; consider liquid or tablet for vegan patients.

When we choose gabapentin:

• Burning, zinging neuropathic features.
• Sleep disruption; nighttime dosing can support rest and pain control.
• Combined with chiropractic to reduce mechanical triggers while stabilizing central excitability.
• Internal medicine oversight ensures renal safety and medication reconciliation.
• References: Argoff, 2014; Enna & McCarson, 2006

Pregabalin: Predictable Kinetics And Faster Steady State

Mechanism and kinetics:

• Pregabalin also binds the alpha-2-delta subunit but has linear pharmacokinetics, reaching steady state in 48–72 hours for quicker titration.

Dosing and efficacy plateau:

• Typical maximum daily dose: 600 mg.
• Diminishing returns often above 450 mg/day; side effects can outpace added benefit, though individual responses vary.

Safety signals:

• Emerging data suggests increased adverse cardiovascular outcomes in some cohorts (diabetic neuropathy, fibromyalgia), including short-term risk within three months of initiation in certain analyses.
• We stratify cardiovascular risk and consider topical-first or non-pharmacologic strategies where appropriate.

When we choose pregabalin:

• Need rapid stabilization of nerve hyperexcitability.
• Non-response or intolerance to gabapentin at appropriate doses.
• Structured cardiovascular evaluation with medical oversight.

Extended-release gabapentin for shingles:

• Gralise and Horizant offer faster titration to higher doses for PHN with improved tolerability.

Antidepressants As Pain Medicines: SNRIs And TCAs

The Descending Pain Modulation Pathway: Why Monoamines Matter

PMS overview:

• Pain signals ascend from dorsal horn to brain but are dynamically modulated by descending pathways.
• PAG → RVM → dorsal horn circuits deploy norepinephrine and serotonin to inhibit pain transmission.
• SNRIs and TCAs increase monoamine availability at these synapses, boosting endogenous analgesia independent of mood effects.

Duloxetine: Broad Pain Indications With Strong Evidence

FDA approvals:

• Fibromyalgia
• Painful diabetic peripheral neuropathy
• Chronic musculoskeletal pain (including chronic low back pain and osteoarthritis)

Osteoarthritis of the knee:

• Duloxetine demonstrates significant reductions in pain and improvements in function—evidence suggests OA pain includes a central sensitization component amenable to DPMS enhancement.

Chronic low back pain:

• Multiple trials show duloxetine reduces pain intensity and improves function; a 60 mg daily dose is standard.

Dosing and tolerability:

• Start at 30 mg daily for 1–2 weeks to minimize nausea, then 60 mg daily.
• Take with food; consider brief use of ondansetron for initiation-related nausea.
• Expect approximately 50% of patients to achieve ≥50% pain reduction.

Clinical positioning:

• Particularly useful when NSAIDs are contraindicated or risky.
• Can be combined with topical and manual therapies for additive benefit.
• References: Skljarevski et al., 2010, Chappell et al., 2011

Milnacipran And Venlafaxine: Additional SNRIs With Distinct Profiles

Milnacipran (Savella):

• SNRI with higher norepinephrine selectivity (~3:1 NE:5-HT).
• FDA-approved for fibromyalgia; brand-only limits access.
• Can produce activating side effects (agitation, tremor, tachycardia, hypertension, insomnia).
• Typical magnitude of response: ~30% pain reduction; integrate with exercise, CBT, sleep optimization.

Venlafaxine (Effexor):

• Acts primarily as an SSRI at lower doses; noradrenergic effects appear above 150–225 mg/day.
• Evidence in pain is modest, mainly for diabetic neuropathy; not a first-line analgesic SNRI.
• Duloxetine retains superior positioning due to approvals and breadth of data.

Tricyclic Antidepressants (TCAs): Old But Effective For Neuropathic Pain

Mechanisms:

• Serotonin/norepinephrine reuptake inhibition enhances descending inhibition.
• Voltage-gated sodium channel blockade (lidocaine-like) reduces ectopic discharges.
• Weak NMDA antagonism, modulating central sensitization.
• Antihistamine (H1) and anticholinergic actions drive many side effects.

Dosing for pain:

• Start 10 mg at bedtime (amitriptyline or nortriptyline), titrate by 10 mg/week.
• Typical effective range: 25–75 mg/day; trial for 6–8 weeks to assess full response.
• Prefer nortriptyline in older adults due to better tolerability.

Safety and interactions:

• Metabolized via CYP2D6; beware strong inhibitors (fluoxetine, paroxetine, bupropion).
• Rare QT prolongation risk increases at high doses; consider baseline ECG in at-risk patients.
• Monitor anticholinergic burden—constipation, urinary retention, cognitive slowing—especially in elderly.

Burning mouth syndrome (BMS):

• Characterized by burning pain in oral mucosa with normal exam; often peri- and postmenopausal women.
• Nortriptyline 10 mg at bedtime, titrating to 25–50 mg/day, frequently produces rapid and meaningful relief within 2–4 weeks—a life-changing intervention.
• References: Kaur & Gupta, 2023, Cytochrome P450

Benzodiazepines: Not Pain Medications

Why Benzodiazepines Fail In Musculoskeletal Pain

Evidence shows

• Benzodiazepines do not improve low back pain outcomes at 10–14 days and can worsen overall analgesia when combined with opioids.
• They enhance GABA-A signaling, producing global CNS depression but not targeted analgesia for musculoskeletal pain.

Critical caution:

• Benzodiazepines can antagonize opioid analgesia, reducing pain relief and increasing risk for respiratory depression—an unacceptable tradeoff.

Clinical stance:

• Reserve benzodiazepines for legitimate indications (acute seizure care, alcohol withdrawal, procedural sedation, specific anxiety disorders) under appropriate specialty oversight.
• Do not position benzodiazepines as pain treatments.
• References: Golob & Wipf, 2014; Park et al., 2015

Muscle Relaxants: Limited And Context-Specific Utility

Class Overview And Mechanisms

Most “muscle relaxants” exert non-specific CNS depression rather than targeted spasm relief. Their modest benefit for acute, non-radiating low back pain (for about a week) often does not justify side effects, and they offer no benefit for sciatica.
Diazepam:

• Not superior to tizanidine or cyclobenzaprine for musculoskeletal pain.
• Risky due to benzodiazepine class effects; not a first-line.

Cyclobenzaprine (Flexeril):

• Structurally similar to TCAs; can influence mood and has accumulation risk at TID dosing (reaching steady state in 3–4 days). Monitor for sedation and cognitive impairment.

Tizanidine (Zanaflex):

• Alpha-2 adrenergic agonist; effective for spasticity.
• Short half-life (~2.5 hours); can be timed to avoid prolonged functional impairment.

Carisoprodol (Soma):

• Metabolizes to meprobamate; Schedule IV due to abuse risk. Rarely appropriate as first-line.

Baclofen:

• GABA-B agonist targeted for spasticity, not simple spasm.
• Abrupt discontinuation can cause severe withdrawal (including seizures); monitor psychiatric and seizure risks.

Clinical principle:

• If topical, manual therapy, and targeted rehabilitation do not suffice for acute spasm, consider short, carefully controlled courses; avoid prolonged use and sedative stacking.
• References: See & Ginzburg, 2008, [Ross, 2011]

Emerging And Specialized Therapies

Low-Dose Naltrexone (LDN): Modulating Neuroinflammation

Mechanism:

• At 1.5–4.5 mg nightly, naltrexone paradoxically calms microglial activation and reduces neuroinflammation, potentially boosting endogenous opioid tone.

Clinical contexts:

• Fibromyalgia, long COVID symptoms, EDS, Crohn’s disease (endoscopic improvements reported), and other chronic pain states driven by neuroimmune dysregulation.
• Must be compounded; titrate carefully over weeks to the maintenance dose.

Opioid interaction:

• LDN’s low dose generally allows acute opioid analgesia to overcome receptor occupancy during surgery or acute injury.
• References: Younger, Parkitny, & McLain, 2014; Metyas et al., 2020

Selective Nav1.8 Inhibitors For Acute Pain: A New Frontier

Zilurgisertib (formerly VX-548):

• Targets Nav1.8 sodium channels on peripheral nociceptors, potentially delivering non-opioid analgesia comparable to hydrocodone 5 mg BID in trials.
• Envisioned for short course acute pain management; remain alert to potential drug interactions (e.g., oral contraceptives).
• Regulatory status is evolving; insurance frameworks may lag, sometimes necessitating “fail-first” protocols with older agents.
• Reference: Vertex Pharmaceuticals, 2024

Opioids: When And How To Use With Precision And Safety

Clinical Realities And Patient Stories

While many chronic pain patients should avoid opioids, a subset with intractable, non-operable conditions may require stable long-term opioid therapy to preserve function.

• Mike, a 56-year-old construction worker with severe facet arthropathy and disc bulges; contraindicated for NSAIDs post-MI and on anticoagulants. Low-dose hydrocodone 1 tab BID lets him remain employed and support his family.
• Sheila, an 84-year-old with prior L4–S1 fusion and adjacent segment degeneration; severe osteoporosis and pulmonary risk preclude surgery. Extended-release oxycodone with short-acting for breakthrough allows daily living and meaningful time with her husband.

These patients are not “drug seekers.” They are people for whom opioids, used with clear safety protocols, maintain dignity and function after other treatments have failed.

Mechanisms And Safe Practice

Opioid receptors:

• Mu mediates analgesia, respiratory depression, and euphoria.
• Receptors in the GI tract slow motility—leading to opioid-induced constipation (OIC).
• Buprenorphine is a partial mu agonist with kappa antagonism and a ceiling on respiratory depression, making it safer than full agonists at higher doses.

Safety checklist:

• Complete physical exam and risk assessment (e.g., Opioid Risk Tool).
• Rule out fixable causes; use opioids as a bridge, not a substitute for definitive care.
• Implement a medication agreement (pain contract).
• Check the PDMP for controlled substance history.
• Document trials and failures of non-opioids and interventions.

Cytochrome P450 variability:

• CYP3A4 and CYP2D6 metabolize many opioids (e.g., hydrocodone, oxycodone, tramadol, fentanyl).
• Morphine, hydromorphone, and oxymorphone bypass CYP450 via glucuronidation—useful when patients report lack of efficacy with CYP-metabolized opioids.

Specialized opioids:

• Buprenorphine for pain (Butrans patch weekly, Belbuca films): excellent for elderly, opioid-naïve, and those requiring consistent low-dose analgesia. Do not routinely stop buprenorphine before surgery.
• Methadone: powerful for neuropathic pain via NMDA antagonism, but dangerous if dosed without expertise due to long, variable half-life (8–59 hours) and dissociation from short analgesic duration (4–6 hours). Titrate slowly; monitor QT prolongation with baseline EKG.

Opioid-induced constipation (OIC):

• Avoid bulk-forming agents (psyllium) that can worsen impaction.
• Use PAMORAs—methylnaltrexone, naloxegol, naldemedine—to block peripheral mu receptors without impacting central analgesia.

Naloxone (Narcan):

• “Naloxone is for a risky drug, not a risky patient.”
• Prescribing naloxone is associated with reduced overdose rates and should be standard in households with opioids.
• Educate on re-dosing needs and immediate 911 activation.
• References: Walley et al., 2013; Pergolizzi, Raffa, & Taylor, 2012

Serotonin Syndrome: Recognize And Act Quickly

Rapid-Onset Toxicity From Serotonergic Excess

Serotonin syndrome results from excessive serotonergic activity, often from drug combinations (SSRIs, MAOIs, triptans, tramadol, dextromethorphan, linezolid, methylene blue, etc.).
Timeline:

• ~30% of cases present within 1 hour of exposure.
• ~60% present within 6 hours.

Clinical triad:

• Neuromuscular: tremor, hyperreflexia, clonus (spontaneous, inducible, ocular).
• Autonomic: hyperthermia, diaphoresis, tachycardia, hypertension, mydriasis.
• Mental status: agitation, confusion, delirium.

Hunter’s Criteria:

• Requires serotonergic exposure plus one of:
  • Spontaneous clonus
  • Inducible clonus + agitation or diaphoresis
  • Ocular clonus + agitation or diaphoresis
  • Tremor + hyperreflexia
  • Hypertonia + temperature > 38°C + ocular or inducible clonus

A focused neurologic exam for clonus often clinches diagnosis—fast, practical, and high-yield.

Management:

• Mild: discontinue offending agents, supportive care.
• Moderate-severe: hospitalization, cooling, benzodiazepines for agitation/myoclonus, cyproheptadine when indicated.
• Severe: ICU-level care.
• References: Dunkley et al., 2003

Functional Medicine Integration: Modulating The Neuroimmune Terrain

Inflammation, Microbiome, And Pain Sensitivity

Systemic inflammation sensitizes nociceptors and central pathways. Gut dysbiosis and increased intestinal permeability allow LPS translocation, activating TLR4 and cytokine cascades (TNF-α, IL-1β, IL-6, IL-17). These pathways correlate with fibromyalgia, chronic low back pain, OA, and mood disorders.
Interventions:

• Mediterranean or elimination diets to reduce inflammatory burden and identify sensitivities.
• Probiotics and prebiotics for microbial diversity.
• Gut mucosal supports (e.g., L-glutamine, zinc carnosine, colostrum) to strengthen tight junctions.
• Evaluate and treat SIBO when present.

Nutritional Deficiencies And Neuropathic Pain

• Vitamin B12: critical for myelin; deficiency common in metformin use, PPIs, vegan diets, and aging.
• Vitamin D: neurosteroid effects; deficiency correlates with increased pain sensitivity and worse outcomes.
• Magnesium: endogenous NMDA antagonist; deficiency is common and contributes to central sensitization.
• Omega-3 fatty acids (EPA/DHA): precursors to resolvins, protectins, maresins—specialized pro-resolving mediators that help terminate inflammation.

Sleep And Circadian Optimization

Sleep deprivation impairs descending inhibition and increases cytokines, reducing pain thresholds.
Assessment:

• PSQI and ESS for sleep quality and daytime sleepiness.
• Screen for OSA—prevalent in cardiometabolic risk populations.

Interventions:

• CBT-I, sleep hygiene, melatonin for circadian support.
• Low-dose TCAs at bedtime for comorbid insomnia.
• CPAP when OSA is diagnosed.
• References: Roehrs et al., 2006

Integrative Chiropractic Care: Mechanically Quieting Pain Drivers

Neurophysiological Mechanisms Of Spinal Manipulation

Chiropractic adjustments:

• Activate Aβ mechanoreceptors, engaging gate control mechanisms that inhibit nociceptive input in the dorsal horn.
• May stimulate PAG-RVM pathways, increasing endogenous analgesia systemically.
• Normalize dysfunctional paraspinal muscle activation patterns to reduce ischemia and pain.
• Reduce perilesional pro-inflammatory cytokines and alter neuroplastic pain processing over time.

Evidence-Based Applications

Chronic low back pain:

• Recommended by ACP guidelines as first-line non-pharmacological care.
• Systematic reviews support clinically meaningful improvements in pain and function.

Cervical radiculopathy:

• Integrative management with manual therapies (adjustment, traction, mobilization) plus membrane stabilizers and SNRIs/TCAs when central sensitization is evident.

Fibromyalgia:

• Modest but growing evidence; benefits include reduced peripheral sensitization triggers, autonomic regulation, and activation of endogenous analgesic systems.

Osteoarthritis:

• Manual therapies improve joint mobility, stimulate synovial movement, reduce soft-tissue tension, and enhance mechanoreceptor-mediated inhibition—complementing duloxetine and topical NSAIDs.

Functional Rehabilitation And Pain Neuroscience Education

Chronic pain drives maladaptive motor patterns—guarding, inhibition, asymmetric loading, deconditioning. We prioritize:

• Motor control retraining and progressive loading.
• Pain Neuroscience Education (PNE) to reconceptualize pain, reduce fear-avoidance, and improve adherence.
• Ergonomic and environmental modifications (desk setup, lifting mechanics, sleep positioning).
• References: Rubinstein et al., 2011, Bialosky et al., 2009

Personal Injury Care: Coordinated Recovery And Documentation

Common Injury Patterns And Pathophysiology

Whiplash-associated disorders (WAD) from MVAs cause:

• Facet joint injury—a frequent source of chronic post-whiplash pain.
• Disc injury, ligamentous strain, and muscular microtears.
• Neurological irritation with potential for central sensitization.
• Goal: Prevent transition from acute to chronic pain through early, integrated intervention.

Our Workflow

Initial evaluation:

• Comprehensive musculoskeletal and neurologic exams.
• Medical review and diagnostics by Dr. Cardenas.
• Identify peripheral drivers and central sensitization features.

Plan development:

• Topical anti-inflammatories, lidocaine or capsaicin for localized neuropathic components.
• Consider gabapentin/pregabalin and duloxetine for neuropathic or central features.
• Chiropractic corrections, rehabilitation, neurodynamic mobilization, and graded exercise.
• Functional medicine supports (inflammation resolution, sleep, nutrient status).

Monitoring:

• Track pain, function, and sleep metrics.
• Adjust doses cautiously; mitigate side effects.
• Advance rehab intensity with pain reduction.

Communication:

• Clear instructions and rationales for adherence.
• Coordination with insurers and legal parties, maintaining detailed documentation.

Patient Communication: Scripts That Make Mechanisms Memorable

• “Topical anti-inflammatories quiet the prostaglandin surge, so the nerve gets less irritated at the source.”
• “Lidocaine blocks sodium channels, like turning down the volume on the pain loudspeaker.”
• “Capsaicin initially turns up TRPV1 heat, then desensitizes the pathway for less pain over time.”
• “Gabapentin slows the nerve’s relay race, stabilizing the membrane so it stops firing too fast.”
• “Pregabalin works similarly but settles into a steady rhythm in 2–3 days; we titrate to balance benefit and side effects.”
• “Chiropractic adjustments and exercises remove mechanical friction causing the inflammation, so the chemistry quiets down.”

Balancing Body and Metabolism- Video

Safety, Risk Stratification, And Dosing Pearls

NSAIDs And Acetaminophen

• NSAID GI risk is systemic; protection with PPIs does not extend to the small intestine.
• Celecoxib can reduce GI risk but does not confer CV safety.
• Educate about acetaminophen maximum dose and product stacking.

Gabapentin And Pregabalin

• Renal dosing required; start low and titrate slowly.
• Monitor for DRESS, sedation, edema, and sleep-disordered breathing.
• Pregabalin: stratify cardiovascular risk, especially in diabetes and fibromyalgia.

Antidepressants

• Duloxetine: start at 30 mg daily, then 60 mg; manage initiation nausea proactively.
• TCAs: start at 10 mg QHS; titrate 10 mg/week; monitor anticholinergic effects, CYP2D6 interactions, and QT risk at higher doses; prefer nortriptyline in older adults.

Benzodiazepines And Muscle Relaxants

• Avoid benzodiazepines as analgesics; they can antagonize opioid efficacy and raise overdose risk.
• Muscle relaxants: limit to short-term, context-specific use; monitor sedation and accumulation.

Opioids

• Implement safety protocols, contracts, PDMP checks, and clear documentation of failed alternatives.
• For OIC, use PAMORAs and avoid bulk-forming agents.
• Prescribe naloxone and educate; naloxone is standard for a risky drug.

Case Patterns We Commonly See And How We Respond

• Acute low back strain:
  • Immediate: diclofenac patch, gentle mobilization.
  • Short term: spinal adjustments, core stabilization.
  • Adjunct: posture coaching; consider lidocaine patches for focal tenderness.
• Postherpetic neuralgia:
  • Immediate: lidocaine patches (12 on/12 off).
  • Medium-term: slow gabapentin titration; consider Qutenza for persistent localized pain.
  • Supports: sleep hygiene, stress reduction, neurodynamic glides.
• Diabetic peripheral neuropathy:
  • Topical capsaicin or Qutenza where appropriate.
  • Systemic: cautious pregabalin with CV monitoring, or gabapentin with renal dosing.
  • Functional: glycemic optimization, nutrient support, foot mechanics assessment.
• CRPS:
  • Consider compounded clonidine gel in select scenarios.
  • Multimodal: desensitization therapy, mirror therapy, graded motor imagery, autonomic regulation.
  • Chiropractic: gentle, pain-aware mobilization; coordinate with pain specialists.

Why Topicals Are Underused—And How We Change That

• Barriers:
  • Habitual reliance on oral medications.
  • Perception that OTC topicals are weak.
  • Limited understanding of peripheral sensitization.
• Solutions:
  • Present evidence that topical NSAIDs can match oral efficacy with less risk.
  • Demonstrate in-clinic relief to build confidence.
  • Integrate topicals into a coherent plan with chiropractic and rehab for visible gains.

The Science Behind Each Choice: Mechanistic Rationale

• Diclofenac: COX inhibition → ↓ prostaglandins → ↓ bradykinin activation → quieter nociceptors.
• Lidocaine: Nav channel blockade → prevents action potential propagation in irritated C-fibers and A-delta fibers.
• Capsaicin: TRPV1 activation → depletes substance P → functional desensitization.
• Gabapentin/Pregabalin: alpha-2-delta binding → ↓ presynaptic excitatory release → stabilized neuronal membranes.
• Duloxetine and SNRIs: enhance descending noradrenergic inhibition in the dorsal horn.
• TCAs: dual monoamine reuptake + sodium channel block + NMDA antagonism.
• Chiropractic and rehab: normalize joint mechanics and motor control → reduce microtrauma, ischemia, and inflammatory mediator release → recalibrate central processing via improved proprioception.

Operational Workflow: How We Integrate Care

• Initial evaluation:
  • Detailed musculoskeletal and neurologic exam.
  • Internal medicine review of medical history and medications.
  • Identify peripheral drivers and central amplification.
• Plan development:
  • Select topical agents to modulate local chemistry.
  • Consider membrane stabilizers and SNRIs/TCAs when neuropathic or central patterns dominate.
  • Prescribe chiropractic corrections and rehab exercises.
  • Add functional medicine supports for inflammation, sleep, and nutrients.
• Monitoring:
  • Track pain, function, and sleep improvements.
  • Adjust doses; mitigate side effects.
  • Progress rehab intensity with pain reductions.
• Communication & documentation:
  • Provide clear instructions and rationales.
  • Coordinate with insurers and referral partners; maintain robust documentation for personal injury and complex care.

Pain Neuroscience Education: Empowering Through Understanding

PNE reconceptualizes pain as a brain output shaped by threat appraisal, context, and prior experience. It reassures that hurt does not always equal harm and promotes active engagement in rehabilitation.
Clinical impact:

• Reduces fear-avoidance and catastrophizing.
• Improves adherence to exercise and pacing strategies.
• Enhances outcomes by aligning expectations with neurophysiology.
• References: Louw et al., 2011

Clinical Observations And Experience

I share observations and approaches through my clinical platforms:

• ChiroMed: https://chiromed.com/
• Professional profile: https://www.linkedin.com/in/dralexjimenez/

These reflections demonstrate how multimodal integration consistently outperforms unimodal care, how early intervention reduces chronification, and how patient engagement and education materially enhance outcomes.

Conclusion: Peripheral-First, Integrative Always

Modern pain care thrives when we modulate peripheral chemistry with topical agents, stabilize neural membranes when needed, and correct mechanical drivers through integrative chiropractic and rehabilitation—under vigilant internal medicine oversight for safety.
With Dr. Maria Guadalupe Cardenas, MD directing medical strategy and risk management, our clinic unites patient-centered science with hands-on care. Whether it’s diclofenac gel at the kitchen sink, a lidocaine patch restoring sleep after shingles, or a carefully titrated pregabalin regimen monitored for cardiovascular signals, our consistent focus is the right mechanism, at the right moment, for the right patient—delivered by a team that treats physiology and people with equal respect.

References

• Argoff, C. E. (2014). The role of anticonvulsants in the management of chronic pain. The Journal of the American Osteopathic Association, 114(1_suppl), eS16–eS21.
• Atchison, J. W., & O’Connor, A. B. (2013). The role of topical analgesics in the management of acute and chronic pain. The Journal of the American Osteopathic Association, 113(4_suppl), eS18–eS24.
• Bally, M., Dendukuri, N., Rich, B., Nadeau, L., Helin-Salmivaara, A., Garbe, E., & Brophy, J. M. (2017). Risk of acute myocardial infarction with NSAIDs in real-world use: Bayesian meta-analysis of individual patient data. BMJ, 357, j1909.
• Bialosky, J. E., Bishop, M. D., Price, D. D., Robinson, M. E., & George, S. Z. (2009). The mechanisms of manual therapy in the treatment of musculoskeletal pain: A comprehensive model. Manual Therapy, 14(5), 531–538.
• Bindu, S., Mazumder, S., & Bandyopadhyay, U. (2020). Non-steroidal anti-inflammatory drugs (NSAIDs) and organ damage: A current perspective. Biochemical Pharmacology, 180, 114147.
• Chappell, A. S., Desaiah, D., Liu-Seifert, H., Zhang, S., Skljarevski, V., Belenkov, Y., & Brown, J. P. (2011). A double-blind, randomized, placebo-controlled study of the efficacy and safety of duloxetine for the treatment of chronic pain due to osteoarthritis of the knee. Pain Practice, 11(1), 33–41.
• Dunkley, E. J. C., Isbister, G. K., Sibbritt, D., Dawson, A. H., & Whyte, I. M. (2003). The Hunter Serotonin Toxicity Criteria: Simple and accurate diagnostic decision rules for serotonin toxicity. QJM: An International Journal of Medicine, 96(9), 635–642.
• Enna, S. J., & McCarson, K. E. (2006). The role of GABA in the mediation and perception of pain. Advances in Pharmacology, 54, 1–27.
• Gatti, A., Sabato, E., Di Paolo, S., Mammucari, M., & Sabato, A. F. (2011). A new topical formulation of diclofenac, an advance in the treatment of acute and chronic pain. Current Medical Research and Opinion, 27(4), 815–824.
• Gerriets, V., Anderson, J., & Nappe, T. M. (2023). Acetaminophen. StatPearls Publishing.
• Golob, A. L., & Wipf, J. E. (2014). Low back pain. Medical Clinics of North America, 98(3), 405–428.
• Kaur, S., & Gupta, V. (2023). Cytochrome P450. StatPearls Publishing.
• Lanza, F. L., Chan, F. K. L., & Quigley, E. M. M. (2009). Guidelines for prevention of NSAID-related ulcer complications. The American Journal of Gastroenterology, 104(3), 728–738.
• Louw, A., Diener, I., Butler, D. S., & Puentedura, E. J. (2011). The effect of neuroscience education on pain, disability, anxiety, and stress in chronic musculoskeletal pain. Archives of Physical Medicine and Rehabilitation, 92(12), 2041–2056.
• Machado, G. C., Maher, C. G., Ferreira, P. H., Pinheiro, M. B., Lin, C. W. C., Day, R. O., McLachlan, A. J., & Ferreira, M. L. (2015). Efficacy and safety of paracetamol for spinal pain and osteoarthritis: Systematic review and meta-analysis of randomized placebo-controlled trials. BMJ, 350, h1225.
• Metyas, S., Chen, C. L., Yeter, K., Solyman, J., & Arkfeld, D. G. (2020). Low dose naltrexone in the treatment of fibromyalgia. Current Rheumatology Reviews, 16(2), 134–139.
• Park, T. W., Saitz, R., Ganoczy, D., Ilgen, M. A., & Bohnert, A. S. B. (2015). Benzodiazepine prescribing patterns and deaths from drug overdose among US veterans receiving opioid analgesics: Case-cohort study. BMJ, 350, h2698.
• Pergolizzi, J. V., Raffa, R. B., & Taylor, R. (2012). A review of buprenorphine for the management of chronic pain. Pain Practice, 13(3), 209–224.
• Qutenza (capsaicin 8%) Prescribing Information. (n.d.). Access FDA.
• Roehrs, T., Hyde, M., Blaisdell, B., Greenwald, M., & Roth, T. (2006). Sleep loss and REM sleep loss are hyperalgesic. Sleep, 29(2), 145–151.
• Rubinstein, S. M., van Middelkoop, M., Assendelft, W. J. J., de Boer, M. R., & van Tulder, M. W. (2011). Spinal manipulative therapy for chronic low-back pain. Cochrane Database of Systematic Reviews, 2011(2), CD008112.
• Skljarevski, V., Desaiah, D., Liu-Seifert, H., Zhang, Q., Chappell, A. S., Detke, M. J., Iyengar, S., Atkinson, J. H., & Backonja, M. (2010). Efficacy and safety of duloxetine in patients with chronic low back pain. Spine, 35(13), E578–E585.
• See, S., & Ginzburg, R. (2008). Choosing a skeletal muscle relaxant. American Family Physician, 78(3), 365–370.
• StatPearls: Acetaminophen; Cytochrome P450.
• Sullivan, M. D., Bentley, S., Fan, M. Y., & Gardner, G. (2018). A single-masked, placebo run-in study of duloxetine for activity-limiting knee pain. Journal of Pain, 10(8), 1–9.
• Twycross, R., Wilcox, R., & Charlesworth, S. (2001). The “why” of pain management. Palliative Medicine, 15(2), 91–92.
• Vertex Pharmaceuticals. (2024). Vertex announces positive results from its phase 3 program for the selective NaV1.8 inhibitor, VX-548, in acute pain.
• Walley, A. Y., Xuan, Z., Hackman, H. H., Quinn, E., Doe-Simkins, M., Sorensen-Alawad, A., … & Ozonoff, A. (2013). Opioid overdose rates and implementation of overdose education and nasal naloxone distribution in Massachusetts: Interrupted time series analysis. BMJ, 346, f174.

SEO tags: integrative pain management, chiropractic care, internal medicine oversight, acetaminophen safety, NSAID cardiovascular risk, topical diclofenac gel, lidocaine patches, capsaicin Qutenza, gabapentin dosing, pregabalin safety, duloxetine chronic pain, tricyclic antidepressants neuropathic pain, burning mouth syndrome nortriptyline, benzodiazepines not for pain, low-dose naltrexone fibromyalgia, Nav1.8 inhibitor acute pain, opioid safety protocols, opioid-induced constipation PAMORA, naloxone access, personal injury whiplash care, pain neuroscience education, El Paso Injury Medical Clinic PA, Dr Maria Guadalupe Cardenas MD, Dr Alex Jimenez DC APRN FNP-BC CFMP IFMCP ATN CCST, functional medicine pain, gut-brain axis pain, sleep and pain management, descending pain modulation system, dorsal horn sensitization, prostaglandins and bradykinin, TRPV1 desensitization