100 Migraine drugs, A to Z: haloperidol

Haloperidol (Haldol) is a psychiatric drug prescribed  for the treatment of schizophrenia, tics in Tourette syndrome, mania in bipolar disorder, nausea and vomiting, delirium, agitation, and acute psychosis.

A cases series published in The Journal of Emergency Medicine in 1995 described six patients who presented with a severe migraine to an emergency room in Toronto and were given haloperidol intravenously. Within an hour all six were either pain-free or significantly improved and none returned to the emergency room within 48 hours.

A double blind placebo controlled study published by Finnish researchers in the journal Headache in 2006 examined the efficacy of 5 mg of haloperidol given intravenously in the treatment of severe migraines. Forty patients were enrolled in the study and 80% (16 patients out of 20) of those who received haloperidol had significant pain relief, compared with 15% (3 patients) in the placebo group. Because the majority of patients had taken regular NSAIDs analgesics and triptans without response, the authors concluded that haloperidol appears to be effective in treatment resistant migraine attacks. However, almost all patients who receive haloperidol complained of side effects, mostly sedation and unpleasant restlessness (akathisia). The side effects were mild to moderate in severity and reversible. The restlessness can be relieved by diphenhydramine (Benadryl).

Haloperidol is one of the neuroleptic drugs, a category that includes droperidol and phenothiazine drugs such as chlorpromazine mentioned in an earlier post. All these drugs have the potential to cause serious and in rare cases permanent neurological side effect of involuntary movements. This is why they are mostly used when other acute migraine therapies have failed. The neurological side effects are more common with continued daily use of haloperidol and other neuroleptics in psychiatric disorders.