Drug interactions
Clozapine + Primaquine
Severity: Major
Clozapine and Primaquine: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both drugs can prolong the QT interval, so together they may raise the risk of serious ventricular arrhythmia. Clozapine also carries risks of myocarditis and hematologic toxicity, and primaquine can cause hemolysis and methemoglobinemia, which complicates monitoring.
What this interaction means in plain words
Clozapine and Primaquine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Clozapine belongs to Central Nervous System; Primaquine belongs to Anti Parasitic.
Why it happens
Additive QTc prolongation, with overlapping hematologic toxicity.
What to do
Obtain a baseline ECG, correct electrolytes, and repeat the ECG during co-therapy. Monitor blood counts closely and consider an alternative antimalarial if QTc is prolonged.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Primaquine
- Pimozide + Primaquine Contraindicated
- Amiodarone + Primaquine Major
- Amisulpride + Primaquine Major
- Anagrelide + Primaquine Major
- Arsenic trioxide + Primaquine Major
- Asenapine + Primaquine Major
Other interactions of Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Frequently asked questions
Can I take Clozapine with Primaquine?
MediHelp rates the interaction as major. Clozapine and Primaquine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both drugs can prolong the QT interval, so together they may raise the risk of serious ventricular arrhythmia. Clozapine also carries risks of myocarditis and hematologic toxicity, and primaquine can cause hemolysis and methemoglobinemia, which complicates monitoring.
How serious is the interaction between Clozapine and Primaquine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain a baseline ECG, correct electrolytes, and repeat the ECG during co-therapy. Monitor blood counts closely and consider an alternative antimalarial if QTc is prolonged.
What other medicines interact with Primaquine?
MediHelp also lists interactions of Primaquine with, for example, Pimozide, Amiodarone, Amisulpride. The full list is on the Primaquine page.
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