Drug interactions
Cimetidine + Propranolol
Severity: Moderate
Cimetidine and Propranolol: 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 increases propranolol plasma levels and can enhance beta-blockade. Patients may experience excessive bradycardia or hypotension.
What this interaction means in plain words
Cimetidine and Propranolol 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; Propranolol belongs to Cardiovascular.
Why it happens
Cimetidine inhibits hepatic CYP enzymes (CYP2D6, CYP1A2) and reduces hepatic blood flow, lowering propranolol first-pass and systemic clearance.
What to do
Monitor heart rate and blood pressure when starting or stopping cimetidine and lower the propranolol dose if needed. Alternatively use famotidine or a less hepatically cleared beta-blocker such as atenolol.
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 Propranolol
- Propranolol + Thioridazine Contraindicated
- Acebutolol + Propranolol Major
- Adrenaline-articaine + Propranolol Major
- Amifostine + Propranolol Major
- Amiodarone + Propranolol Major
- Arformoterol + Propranolol Major
Frequently asked questions
Can I take Cimetidine with Propranolol?
MediHelp rates the interaction as moderate. Cimetidine and Propranolol 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 increases propranolol plasma levels and can enhance beta-blockade. Patients may experience excessive bradycardia or hypotension.
How serious is the interaction between Cimetidine and Propranolol?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor heart rate and blood pressure when starting or stopping cimetidine and lower the propranolol dose if needed. Alternatively use famotidine or a less hepatically cleared beta-blocker such as atenolol.
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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