Diltiazem for clozapine-induced generalized hyperhidrosis

BACKGROUND: Clozapine can be associated with significant side effects and tolerability issues. Hyperhidrosis occurs less commonly and is unanticipated by clinicians because of clozapine's significant anticholinergic activity. CASE REPORT: A 34-year-old female developed clozapine-induced nocturnal, generalized hyperhidrosis following initial titration to 400 mg/day. Dose reduction did not decrease the side effect. Treatment with an anticholinergic medication could not be initiated because of constipation. Treatment with a beta blocker resulted in worsening of asthma. Treatment with a calcium channel blocker, diltiazem CD 180 mg/day, resulted in a significant reduction in hyperhidrosis. CONCLUSION: This case supports the use of calcium channel blockers to reduce clozapine-induced hyperhidrosis and offers an alternative to anticholinergic medications that may negatively impact clozapine tolerability.