Drug interactions
Flucytosine + Lomustine
Severity: Major
Flucytosine and Lomustine: 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
Flucytosine can suppress bone marrow, particularly with renal impairment. Combined with lomustine, which causes delayed myelosuppression, the risk of severe cytopenias is increased.
What this interaction means in plain words
Flucytosine and Lomustine 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.
Flucytosine belongs to Anti Fungals; Lomustine belongs to Oncology.
Why it happens
Additive bone marrow suppression.
What to do
Monitor complete blood counts and renal function closely, and measure flucytosine levels if available. Reduce doses or stop one agent if significant cytopenia develops.
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 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
Other interactions of Flucytosine
- Amphotericin b + Flucytosine Major
- Deferiprone + Flucytosine Major
- Flucytosine + Ifosfamide Major
- Fluconazole + Flucytosine Moderate
- Flucytosine + Ganciclovir Moderate
- Flucytosine + Hydroxycarbamide Moderate
Frequently asked questions
Can I take Flucytosine with Lomustine?
MediHelp rates the interaction as major. Flucytosine and Lomustine 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. Flucytosine can suppress bone marrow, particularly with renal impairment. Combined with lomustine, which causes delayed myelosuppression, the risk of severe cytopenias is increased.
How serious is the interaction between Flucytosine and Lomustine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor complete blood counts and renal function closely, and measure flucytosine levels if available. Reduce doses or stop one agent if significant cytopenia develops.
What other medicines interact with Lomustine?
MediHelp also lists interactions of Lomustine with, for example, Adenovirus types 4 and 7 live, Bcg vaccine live, Influenza virus vaccine quadrivalent intranasal. The full list is on the Lomustine page.
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