Drug interactions
Mefloquine + Venlafaxine
Severity: Moderate
Mefloquine and Venlafaxine: moderate 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
Venlafaxine can prolong the QT interval, particularly in overdose or at high doses, and mefloquine adds to this effect. Both drugs can also cause neuropsychiatric effects and lower the seizure threshold.
What this interaction means in plain words
Mefloquine and Venlafaxine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Mefloquine belongs to Anti Parasitic; Venlafaxine belongs to Central Nervous System.
Why it happens
Additive QT prolongation and neuropsychiatric effects (pharmacodynamic).
What to do
Check a baseline ECG and electrolytes, and monitor for palpitations, syncope, seizures and mood changes. Consider an alternative antimalarial in patients with cardiac risk factors or psychiatric history.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Mefloquine and Venlafaxine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
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 Venlafaxine
- Isocarboxazid + Venlafaxine Contraindicated
- Methylene blue + Venlafaxine Contraindicated
- Phenelzine + Venlafaxine Contraindicated
- Procarbazine + Venlafaxine Contraindicated
- Rasagiline + Venlafaxine Contraindicated
- Safinamide + Venlafaxine Contraindicated
Frequently asked questions
Can I take Mefloquine with Venlafaxine?
MediHelp rates the interaction as moderate. Mefloquine and Venlafaxine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Venlafaxine can prolong the QT interval, particularly in overdose or at high doses, and mefloquine adds to this effect. Both drugs can also cause neuropsychiatric effects and lower the seizure threshold.
How serious is the interaction between Mefloquine and Venlafaxine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check a baseline ECG and electrolytes, and monitor for palpitations, syncope, seizures and mood changes. Consider an alternative antimalarial in patients with cardiac risk factors or psychiatric history.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
