Drug interactions
Cimetidine + Tafenoquine
Severity: Moderate
Cimetidine and Tafenoquine: 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
Tafenoquine inhibits the renal transporters OCT2 and MATE, through which cimetidine is secreted into urine. Cimetidine exposure may therefore rise, increasing the chance of concentration-related adverse effects.
What this interaction means in plain words
Cimetidine and Tafenoquine 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.
Cimetidine belongs to Gastrointestinal Tract; Tafenoquine belongs to Anti Parasitic.
Why it happens
Tafenoquine inhibits OCT2 and MATE-mediated renal tubular secretion of cimetidine, reducing its clearance.
What to do
Avoid the combination where possible; if both are needed, monitor for cimetidine adverse effects such as CNS effects and consider a lower cimetidine dose or an alternative acid suppressant.
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 Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram Major
Other interactions of Tafenoquine
- Dofetilide + Tafenoquine Major
- Alogliptin-metformin + Tafenoquine Moderate
- Amantadine + Tafenoquine Moderate
- Amiloride + Tafenoquine Moderate
- Canagliflozin-metformin + Tafenoquine Moderate
- Cisplatin + Tafenoquine Moderate
Frequently asked questions
Can I take Cimetidine with Tafenoquine?
MediHelp rates the interaction as moderate. Cimetidine and Tafenoquine 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. Tafenoquine inhibits the renal transporters OCT2 and MATE, through which cimetidine is secreted into urine. Cimetidine exposure may therefore rise, increasing the chance of concentration-related adverse effects.
How serious is the interaction between Cimetidine and Tafenoquine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible; if both are needed, monitor for cimetidine adverse effects such as CNS effects and consider a lower cimetidine dose or an alternative acid suppressant.
What other medicines interact with Cimetidine?
MediHelp also lists interactions of Cimetidine with, for example, Dofetilide, Fezolinetant, Alfentanil. The full list is on the Cimetidine page.
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