Polypharmacy in Maintenance of Bipolar Disorder

To track the outcomes of bipolar patients who had remitted from an acute manic episode on single- and multiple-drug regimens including lithium (LI), valproate (VPA), and carbamazepine (CBZ), in order to compare relapse rates on 1, 2, or 3 medications.

Following treatment of an acute manic episode and a 1-month period of no signs of mood episodes, patients were evaluated at 1- to 2-month intervals as to the kind of regimen required to maintain their stability while continuing on this regimen for 2 years. Medication regimens included 1, 2, or 3 of the following drugs: LI, VPA, and/or CBZ. The 3 medication groups were followed from entry into the study through 3 possible end points based on the Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition checklist: "NO-Relapse," "Relapse," or "Dropped out."

Of the 1312 patients included in the study and followed up for 2 years, 281 patients (21.4%) were maintained on a single drug (LI, VPA, or CBZ), 852 (65%) on 2 drugs, and 179 (13.6%) on 3 or more drugs. A smaller percentage of patients on 1 medication had NO-Relapse for 2 years (22.8%), compared with patients on 2 medications (43.9%) and patients on 3 or more medications (41.9%): χ2 = 40.3, P < 0.001.

This study showed that overall, of the bipolar patients who were asymptomatic at 1 month, a smaller percentage of patients on 1 medication continued to be stable for 2 years, compared with patients on 2 medications and patients on 3 or more medications.