Drug interactions
Carmustine + Cimetidine
Severity: Major
Carmustine and Cimetidine: major 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 has been reported to increase carmustine-related bone marrow suppression. This may produce deeper or more prolonged leukopenia and thrombocytopenia.
What this interaction means in plain words
Carmustine and Cimetidine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Carmustine belongs to Oncology; Cimetidine belongs to Gastrointestinal Tract.
Why it happens
Cimetidine may reduce hepatic metabolism of carmustine and possibly adds to marrow suppression; the mechanism is not fully established.
What to do
Avoid the combination where possible and use famotidine or another acid suppressant instead. If given together, monitor complete blood counts closely.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Cimetidine + Citalopram Major
- Cimetidine + Clozapine Major
Other interactions of Carmustine
- Carmustine + Pentostatin Contraindicated
- Carmustine + Chlorambucil Major
- Carmustine + Cyclophosphamide Major
- Carmustine + Dacarbazine Major
- Carmustine + Fingolimod Major
- Carmustine + Lomustine Major
Frequently asked questions
Can I take Carmustine with Cimetidine?
MediHelp rates the interaction as major. Carmustine and Cimetidine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Cimetidine has been reported to increase carmustine-related bone marrow suppression. This may produce deeper or more prolonged leukopenia and thrombocytopenia.
How serious is the interaction between Carmustine and Cimetidine?
MediHelp rates it major, 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 and use famotidine or another acid suppressant instead. If given together, monitor complete blood counts closely.
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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