Drug interactions
Cimetidine + Lomustine
Severity: Moderate
Cimetidine and Lomustine: 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 has been reported to increase the bone marrow toxicity of nitrosoureas such as lomustine. This may deepen leukopenia and thrombocytopenia.
What this interaction means in plain words
Cimetidine and Lomustine 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; Lomustine belongs to Oncology.
Why it happens
Proposed inhibition of hepatic metabolism of lomustine, possibly combined with additive myelosuppression; the mechanism is not firmly established.
What to do
Monitor complete blood counts closely, or use an alternative acid suppressant such as a proton pump inhibitor or famotidine during lomustine therapy.
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 Lomustine
- Adenovirus types 4 and 7 live + Lomustine Contraindicated
- Bcg vaccine live + Lomustine Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Lomustine Contraindicated
- Lomustine + Measles mumps and rubella vaccine Contraindicated
- Lomustine + Measles mumps and rubella vaccine live Contraindicated
- Lomustine + Measles mumps rubella and varicella vaccine live Contraindicated
Frequently asked questions
Can I take Cimetidine with Lomustine?
MediHelp rates the interaction as moderate. Cimetidine and Lomustine 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 has been reported to increase the bone marrow toxicity of nitrosoureas such as lomustine. This may deepen leukopenia and thrombocytopenia.
How serious is the interaction between Cimetidine and Lomustine?
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 complete blood counts closely, or use an alternative acid suppressant such as a proton pump inhibitor or famotidine during lomustine therapy.
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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