Drug interactions
Cimetidine + Mizolastine
Severity: Moderate
Cimetidine and Mizolastine: 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
Cimetidine can increase mizolastine concentrations modestly. Mizolastine can prolong the QT interval, so higher exposure is undesirable, though the observed increase is small.
What this interaction means in plain words
Cimetidine and Mizolastine 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.
Why it happens
Cimetidine inhibits hepatic metabolism of mizolastine, including CYP3A4-mediated pathways.
What to do
Use with caution in patients with QT risk factors and consider an alternative H2 antagonist or antihistamine; monitor for sedation and palpitations.
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
Frequently asked questions
Can I take Cimetidine with Mizolastine?
MediHelp rates the interaction as moderate. Cimetidine and Mizolastine 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 can increase mizolastine concentrations modestly. Mizolastine can prolong the QT interval, so higher exposure is undesirable, though the observed increase is small.
How serious is the interaction between Cimetidine and Mizolastine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use with caution in patients with QT risk factors and consider an alternative H2 antagonist or antihistamine; monitor for sedation and palpitations.
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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