BLOOD DYSCRASIAS WITH CARBAMAZEPINE AND VALPROATE - A PHARMACOEPIDEMIOLOGIC STUDY OF 2,228 PATIENTS AT RISK

Objective: The purpose of this study was to determine the occurrence o f leukopenia and other blood dyscrasias associated with psychiatric us e of carbamazepine and valproate. Method: Rates of WBC counts of 3,000 -4,000/mm(3) (moderate leukopenia) and <3,000/mm(3) (severe leukopenia ), platelet counts of <100,000/mm(3), and hematocrit <30% were identif ied among 2,228 treated patients at risk among 11,720 patients admitte d to McLean Hospital over 4 years (1989-1993). Patients who received c arbamazepine or valproate and had a blood dyscrasia not associated wit h a relevant medical condition were compared to patients treated with imipramine or desipramine. Results: Of 977 patients treated with carba mazepine, 2.1% experienced leukopenia (16 moderate cases, five severe) . Time to 50% risk was 16 days, and recovery occurred within about 6 d ays after carbamazepine was stopped. For 1,251 patients given valproat e, the occurrence of leukopenia was 0.4% (three moderate cases, two se vere). The occurrence of leukopenia in 1,031 patients given the tricyc lic antidepressants was 0.3% (two moderate cases, one severe). The obs erved occurrence of moderate leukopenia with carbamazepine was 6.9 and 7.3 times higher than that with valproate and antidepressants, respec tively. Conclusions: Severe blood dyscrasias were uncommon in psychiat ric patients given carbamazepine and were about as rare with valproate as with imipramine or desipramine. Most important, in this cohort of 2,228 patients exposed to carbamazepine and valproate, there were no l ife-threatening cases.