Drug interactions
Mefloquine + Ritonavir
Severity: Major
Mefloquine and Ritonavir: major interaction.
Last updated
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
Ritonavir markedly raises mefloquine exposure and both drugs can prolong the QT interval. This raises the risk of arrhythmia and mefloquine neuropsychiatric toxicity, and mefloquine labeling advises against use with ritonavir.
What this interaction means in plain words
Mefloquine and Ritonavir 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.
Mefloquine belongs to Anti Parasitic; Ritonavir belongs to Anti Virals.
Why it happens
Strong CYP3A4 inhibition by ritonavir reduces mefloquine clearance, with additive QTc prolongation.
What to do
Avoid the combination and use an alternative antimalarial. If unavoidable, obtain an ECG and monitor for neuropsychiatric symptoms.
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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Other interactions of Mefloquine
- Arsenic trioxide + Mefloquine Contraindicated
- Dronedarone + Mefloquine Contraindicated
- Ibutilide + Mefloquine Contraindicated
- Levoketoconazole + Mefloquine Contraindicated
- Mefloquine + Nilotinib Contraindicated
- Mefloquine + Pimozide Contraindicated
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Mefloquine with Ritonavir?
MediHelp rates the interaction as major. Mefloquine and Ritonavir 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. Ritonavir markedly raises mefloquine exposure and both drugs can prolong the QT interval. This raises the risk of arrhythmia and mefloquine neuropsychiatric toxicity, and mefloquine labeling advises against use with ritonavir.
How serious is the interaction between Mefloquine and Ritonavir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination and use an alternative antimalarial. If unavoidable, obtain an ECG and monitor for neuropsychiatric symptoms.
What other medicines interact with Mefloquine?
MediHelp also lists interactions of Mefloquine with, for example, Arsenic trioxide, Dronedarone, Ibutilide. The full list is on the Mefloquine page.
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