Critical5-HT3 serotonin receptor antagonist×Atypical antipsychotic, selective 5-HT2A inverse agonist
Updated · Methodology
Mechanism
Both drugs prolong QT (pimavanserin 5-8 ms, ondansetron 10-15 ms). Additive – torsades risk.
Symptoms
Syncope, torsades de pointes in patients with additional risk factors.
Management
Combination contraindicated. Use metoclopramide for nausea.
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.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- FDA: Nuplazid (pimavanserin) prescribing information (2023)– FDA Nuplazid label