Phenothiazines neither relieve pain nor potentiate opioid analgesia. Sedation and orthostatic hypotension may be pronounced, so one should start with small doses. Prolonged use of phenothiazines can lead to tardive dyskinesia. Extrapyramidal manifestations can occur, and can be treated with diphenhydramine. May relieve brief lancinating pains arising from peripheral nerve syndromes such as trigeminal neuralgia, postherpetic neuralgia, glossopharyngeal neuralgia, and posttraumatic neuralgia.
Nerve injury caused by cancer or cancer therapy sometimes gives rise to such tic-like pains.
Controlled clinical trials in diabetic neuropathy and postherpetic neuralgia show that gabapentin has an efficacy similar to the tricyclic antidepressants. Gabapentin doses must be reduced considerably for patients with renal insufficiency. Carbamazepine, clonazepam, and baclofen are also used. Anticonvulsants were effective for trigeminal neuralgia, diabetic neuropathy, and migraine prophylaxis. Clonidine - has been approved by the FDA for the treatment of pain.