AN OPEN-LABEL STUDY OF THE THERAPEUTIC EFFICACY OF HIGH-DOSE FAMOTIDINE ADJUVANT PHARMACOTHERAPY IN SCHIZOPHRENIA - PRELIMINARY EVIDENCE FOR TREATMENT EFFICACY

Histaminergic projections innervate brain areas implicated in the path ophysiology of schizophrenia. In a previous open-label study, there wa s the suggestion that famotidine, an H-2 histamine-receptor antagonist , possessed adjuvant therapeutic properties when added to the stable n euroleptic medication 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 dis ease. In this study, we examined 18 patients fulfilling DSM-III-R crit eria for schizophrenia and schizoaffective disorder who had famotidine (100 mg/day) added to their stable neuroleptic medication regimen. Pa tients were rated on baseline, weekly thereafter, and 1 week after fam otidine discontinuation, by using the Brief Psychiatric Rating Scale ( BPRS), Schedule for the Assessment of Negative Symptoms (SANS), and th e Clinical Global Impression (CGI). On all of these outcome measures, statistically significant improvements suggestive of a beneficial adju nctive effect of famotidine were found. Famotidine (100 mg/day) was we ll tolerated by the study subjects. There was a wide range of famotidi ne blood levels achieved at the end of 3 weeks of famotidine adjunctiv e treatment, but these blood levels did not correlate with BPRS or SAN S score changes. However, the patients with the greatest improvement i n BPRS scores (and without concomitant deterioration in SANS scores) h ad some of the higher famotidine levels found in the study. Double-bli nd studies further assessing the potential adjunctive benefit of famot idine in the treatment of schizophrenia are indicated.