Neurology/Neuropathic pain drugs

Neuropathic pain drugs

also: amitriptyline · duloxetine · gabapentin · pregabalin · trigeminal neuralgia

Overview

First-line neuropathic-pain agents (choose one, switch if it fails) and the special cases — trigeminal neuralgia and diabetic neuropathy.

Mechanism

Amitriptyline (TCA) and duloxetine (SNRI) augment descending noradrenergic/serotonergic inhibition. Gabapentin/pregabalin bind the α2δ subunit of voltage-gated Ca²⁺ channels → ↓excitatory neurotransmitter release. Carbamazepine stabilises Na⁺ channels (trigeminal neuralgia).

Indications

Neuropathic pain (diabetic, post-herpetic, etc.)
Trigeminal neuralgia (carbamazepine)
Fibromyalgia (duloxetine/amitriptyline)

The agents

Amitriptyline / duloxetine / gabapentin / pregabalinfirst-line (any one)

NICE: try one first-line; if it fails, switch to another. Duloxetine first-line specifically for diabetic neuropathy.

Carbamazepinetrigeminal neuralgia

First-line for trigeminal neuralgia.

Capsaicin creamlocalised

topical

Localised neuropathic pain.

Adverse effects

Gabapentinoids: sedation, dependence, respiratory depression with opioidsserious

Now controlled drugs (Class C) — misuse potential.

Amitriptyline: anticholinergic effects, overdose cardiotoxicitycommon

Duloxetine: nausea, hypertensioncommon

Cautions & contraindications

Amitriptyline in recent MI / arrhythmiaall

Gabapentinoids + opioids (respiratory depression)all

Interactions

Gabapentinoid + opioid (respiratory depression)
Duloxetine + other serotonergics

Monitoring & kinetics

Pain response (review/switch if inadequate); mood

Oral, titrated. Standard analgesics (the WHO ladder) work poorly in neuropathic pain.

Source: NICE CG173 — Neuropathic pain · BNF — Neuropathic pain