Drug interactions
Lacosamide + Ritonavir
Severity: Moderate
Lacosamide and Ritonavir: 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
Ritonavir is a strong CYP3A4 inhibitor and may modestly raise lacosamide levels. Lacosamide can prolong the PR interval, and caution is warranted in patients with conduction disease or on other PR-prolonging drugs.
What this interaction means in plain words
Lacosamide and Ritonavir 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.
Lacosamide belongs to Central Nervous System; Ritonavir belongs to Anti Virals.
Why it happens
CYP3A4 inhibition by ritonavir reduces lacosamide metabolism, and both drugs may affect cardiac conduction.
What to do
Obtain a baseline ECG in patients with cardiac conduction abnormalities and monitor PR interval and symptoms such as dizziness or syncope. Reduce the lacosamide dose if adverse effects emerge.
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?
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Other interactions of Lacosamide
- Lacosamide + Zuranolone Major
- Atazanavir + Lacosamide Moderate
- Carbamazepine + Lacosamide Moderate
- Cenobamate + Lacosamide Moderate
- Clarithromycin + Lacosamide Moderate
- Daridorexant + Lacosamide Moderate
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 Lacosamide with Ritonavir?
MediHelp rates the interaction as moderate. Lacosamide and Ritonavir 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. Ritonavir is a strong CYP3A4 inhibitor and may modestly raise lacosamide levels. Lacosamide can prolong the PR interval, and caution is warranted in patients with conduction disease or on other PR-prolonging drugs.
How serious is the interaction between Lacosamide and Ritonavir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain a baseline ECG in patients with cardiac conduction abnormalities and monitor PR interval and symptoms such as dizziness or syncope. Reduce the lacosamide dose if adverse effects emerge.
What other medicines interact with Lacosamide?
MediHelp also lists interactions of Lacosamide with, for example, Zuranolone, Atazanavir, Carbamazepine. The full list is on the Lacosamide page.
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