Major
Aripiprazole × ritonavir
Atypical antipsychotic – dopamine partial agonist×HIV protease inhibitor / pharmacokinetic booster
Mechanism
Ritonavir inhibits CYP3A4 (and weakly CYP2D6). Aripiprazole rises 2-3 fold. Enhanced extrapyramidal effects and sedation.
Symptoms
Sedation, akathisia, dyskinesia.
Management
Halve aripiprazole dose.
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.