Neuropathic Pain: Why Painkillers Fail and Nerve Drugs Work
Some of the worst pain in medicine comes not from injured tissue but from injured nerves — the burning, shooting, electric pain of diabetes, shingles or nerve damage. And it plays by different rules: ordinary painkillers, even morphine, barely help. The drugs that DO work are borrowed from psychiatry and epilepsy, and understanding why is the key to treating this pain well.
In the analgesic ladder article, we drew a crucial line between two kinds of pain. Ordinary (nociceptive) pain comes from tissue damage — a cut, a broken bone, an inflamed joint — where the pain nerves are working correctly, reporting real injury. Neuropathic pain is completely different: it comes from damage to the nerves themselves. When a nerve is damaged — by diabetes, by the shingles virus, by injury, by trapped or compressed nerves — it can start firing abnormally, sending pain signals when there's nothing actually wrong to report. Patients describe it in distinctive ways: burning, shooting, stabbing, electric-shock, pins-and-needles, or a numb-but-painful quality. And crucially, this pain responds poorly to the standard painkillers of the last articles. Even strong opioids often barely touch it. Treating neuropathic pain well means recognising it and reaching for a completely different set of drugs.
The drugs that work — and why they're familiar
Antidepressants and anticonvulsants calm the over-firing nerves. The treatments for neuropathic pain are drawn from two other chapters of this book, and once you see why, it makes perfect sense. The problem is over-excitable, misfiring nerves — so the drugs that help are ones that calm down excitable nerves. Two families do this. The anticonvulsants (from the epilepsy chapter) — especially the 'gabapentinoids', gabapentin and pregabalin — quieten the abnormal electrical firing of the damaged nerves, exactly as they calm the over-firing that causes seizures. And certain antidepressants — the tricyclic amitriptyline, and the SNRI duloxetine (from the CNS chapter) — relieve neuropathic pain by boosting the body's own pain-dampening pathways in the spinal cord, an effect separate from their action on mood (which is why they work at doses often lower than those used for depression). These are the first-line drugs for neuropathic pain: not the NSAIDs and opioids of ordinary pain, but the nerve-calming drugs from epilepsy and psychiatry. Additional options include specific treatments for specific conditions — for example, topical agents like capsaicin or lidocaine patches for localised nerve pain. The key skill is simply the recognition: identify the pain as neuropathic (its burning, shooting, electric quality is the clue), and then reach for a gabapentinoid or an antidepressant rather than climbing the conventional analgesic ladder.
- Neuropathic pain comes from damaged nerves (diabetes, shingles, injury) — burning, shooting, electric quality.
- It responds POORLY to ordinary painkillers, including opioids — different pain, different drugs.
- First-line: gabapentinoids (gabapentin, pregabalin — from epilepsy) calm the misfiring nerves.
- And antidepressants (amitriptyline, duloxetine — from CNS) boost pain-dampening pathways (separate from mood effect).
- The key skill is RECOGNISING neuropathic pain — then choosing a nerve drug, not the analgesic ladder.
Neuropathic pain is the ultimate reward for treating this whole book as a connected web rather than separate chapters. The drugs that relieve it come from epilepsy (gabapentin, pregabalin) and psychiatry (amitriptyline, duloxetine) — and they work for exactly the reason they work in those diseases. Epilepsy is over-firing brain cells; neuropathic pain is over-firing pain nerves; the same drug that calms one calms the other. Depression drugs boost the same nerve-signalling pathways that also happen to dampen pain in the spinal cord. So the treatment for a diabetic patient's burning feet lives in the chapters on seizures and mood, not the chapter on pain. This is the deepest lesson of pharmacology: drugs are defined by the mechanism they act on, and once you understand that mechanism, you can carry a drug across the artificial boundaries between diseases and specialties — and reach for exactly the right one in a place you'd never expect to find it.
- Climbing the opioid ladder for neuropathic pain — it responds poorly; use nerve-calming drugs.
- Not recognising the burning/shooting/electric quality as a clue to neuropathic pain.
- Assuming an antidepressant is 'for depression' here — it treats the pain (often at lower doses).
- Using NSAIDs alone for nerve pain — they don't address the misfiring nerve.
What are the first-line drugs for neuropathic (nerve) pain?
- Neuropathic pain comes from damaged nerves (burning/shooting/electric), not tissue injury.
- It responds poorly to NSAIDs and opioids — different pain needs different drugs.
- First-line: gabapentinoids (from epilepsy) and antidepressants (from CNS) that calm over-firing nerves.
- The key is recognising nerve pain, then reaching for the right (non-obvious) drug.
- Katzung BG. Basic & Clinical Pharmacology — Management of neuropathic pain.
- Brunton LL, et al. Goodman & Gilman's The Pharmacological Basis of Therapeutics — Adjuvant analgesics for neuropathic pain.
- NICE / IASP — Neuropathic pain management guidelines.
- Rang HP, Dale MM, et al. Rang & Dale's Pharmacology — Neuropathic pain.
