After administering 200 mg of the antihistamine famotidine daily for 4 weeks, researchers in Finland saw a significant reduction of schizophrenia symptoms in patients.
Led by professor Jesper Ekelund, MD, PhD, at the University of Helsinki, researchers increased the standard dosing of the heartburn drug famotidine five-fold in an attempt to break the blood-brain barrier, which typically protects the brain from the histamine. At a ramped up dosage of 200 mg, however, the drug penetrated the barrier and effectively blocked the histamine H2 receptor in the brain and affected signaling substances shown to be involved in schizophrenia.
The research, published online in advance of the August issue of the Journal of Clinical Psychopharmacology, involved 30 patients with treatment-resistent schizophrenia who were divided into two groups: one that received famotidine and one that received placebo. Patients receiving the daily dose of famotidine reported decreased symptoms after a week. After a month, the symptoms had decreased by a statistically significant amount.
Patients receiving placebo reported no change in symptoms.
Dr. Ekelund cautioned that providers should avoid using famotidine for schizophrenia treatment until the 200 mg dose has been proven safe over the long term.
“However, our study shows that the histamine system in the brain offers a novel approach to treating psychosis,” Dr. Ekelund said. “This should lead to increased efforts by the pharmaceutical industry to develop medications based on this histamine-based mechanism.”
Researchers are collaborating with the Karolinska Institutet in Sweden to replicate their findings in a larger study.
1. Meskanen K, Ekelund H, Laitinen J, et al. A randomized clinical trial of histamine 2 receptor antagonism in treatment-resistant schizophrenia. Journal of Clinical Psychopharmacology. 2013;33:472-478. [Epub ahead of print].