. Author manuscript; available in PMC: 2017 Mar 29.

Published in final edited form as: Nat Rev Dis Primers. 2017 Feb 16;3:17002. doi: 10.1038/nrdp.2017.2

Table 1.

Available pharmacotherapy for neuropathic pain

Drug	Mechanisms of action	NNT^* (range)	Adverse effects	Precautions and contraindications
*Tricyclic antidepressants*

Nortriptyline, desipramine, amitriptyline, clomipramine and imipramine	Monoamine reuptake inhibition, sodium channel blockade and anticholinergic effects	3.6 (3–4.4)	Somnolence, anticholinergic effects and weight gain	• Cardiac disease, glaucoma, prostatic adenoma and seizure • High doses should be avoided in adults >65 years of age and in those with amyloidosis

*Serotonin-noradrenaline reuptake inhibitors*

Duloxetine	Serotonin and noradrenaline reuptake inhibition	6.4 (5.2–8.2)	Nausea, abdominal pain and constipation	• Hepatic disorder and hypertension • Use of tramadol

Venlafaxine	Serotonin and noradrenaline reuptake inhibition	6.4 (5.2–8.2)	Nausea and hypertension at high doses	• Cardiac disease and hypertension • Use of tramadol

*Calcium channel α₂δ ligands*

Gabapentin, extended-released gabapentin and enacarbil, and pregabalin	Act on the α₂δ subunit of voltage-gated calcium channels, which decrease central sensitization	• 6.3 (5–8.4 for gabapentin) • 8.3 (6.2–13 for extended-released gabapentin and enacarbil) • 7.7 (6.5–9.4 for pregabalin)	Sedation, dizziness, peripheral oedema and weight gain	Reduce dose in patients with renal insufficiency

*Topical lidocaine*

Lidocaine 5% plaster	Sodium channel blockade	Not reported	Local erythema, itching and rash	None

Capsaicin high-concentration patch (8%)	Transient receptor potential cation channel subfamily V member 1 agonist	10.6 (7.4–19)	Pain, erythema, itching and rare cases of high blood pressure (initial increase in pain)	No overall impairment of sensory evaluation after repeated applications and caution should be taken in progressive neuropathy

*Opioids*

Tramadol	μ-Receptor agonist and monoamine reuptake inhibition	4.7 (3.6–6.7)	Nausea, vomiting, constipation, dizziness and somnolence	History of substance abuse, suicide risk and use of antidepressant in elderly patients

Morphine and oxycodone	μ-Opioid receptor agonists; oxycodone might also cause κ-opioid receptor antagonism	4.3 (3.4–5.8)	Nausea, vomiting, constipation, dizziness and somnolence	History of substance abuse, suicide risk and risk of misuse in the long term

Neurotoxin

Botulinum toxin A	Acetylcholine release inhibitor and neuromuscular-blocking agent; potential effects on mechanotransduction and central effects in neuropathic pain	1.9 (1.5–2.4)	Pain at injection site	Known hypersensitivity and infection of the painful area

Number needed to treat (NNT) for 50% pain relief represents the number of patients necessary to treat to obtain one responder more than the comparison treatment, typically placebo¹⁰¹.