Histaminergic projections innervate brain areas implicated in the pathophysiology of
schizophrenia. In a previous open-label study, there was the suggestion that
famotidine, and H2
histamine-receptor antagonist, possessed adjuvant therapeutic properties when added to the stable
neuroleptic medications regimens of 10 treatment-refractory patients. In that study, the maximal dosage of
famotidine was limited to 40 mg/day, the recommended maximal dosage for the treatment of
peptic ulcer disease. In this study, we examined 18 patients fulfilling DSM-III-R criteria for
schizophrenia and
schizoaffective disorder who had
famotidine (100 mg/day) added to their stable
neuroleptic medication regimen. Patients were rated on baseline, weekly thereafter, and 1 week after
famotidine discontinuation, by using the Brief Psychiatric Rating Scale (BPRS), Schedule for the Assessment of Negative Symptoms (SANS), and the Clinical Global Impression (CGI). On all of these outcome measures, statistically significant improvements suggestive of a beneficial adjunctive effect of
famotidine were found.
Famotidine (100 mg/day) was well tolerated by the study subjects. There was a wide range of
famotidine blood levels achieved at the end of 3 weeks of
famotidine adjunctive treatment, but these blood levels did not correlate with BPRS or SANS score changes. However, the patients with the greatest improvement in BPRS scores (and without concomitant deterioration in
SAND scores) had some of the higher
famotidine levels found in the study. Double-blind studies further assessing the potential adjunctive benefit of
famotidine in the treatment of
schizophrenia are indicated.