Moderate
Amlodipine × Haloperidol
Calcium channel blockers (dihydropyridines)×First-generation antipsychotics. Butyrophenone derivatives
Mechanism
Additive hypotension (haloperidol blocks α1-adrenoceptors) and sedation. Haloperidol prolongs QT; amlodipine does not contribute to QT.
Symptoms
Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk.
Management
Avoid the combination, especially with parenteral haloperidol. Alternative antipsychotics with minimal α1-blockade: olanzapine or aripiprazole.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.