Drug interactions
Cimetidine + Pefloxacin
Severity: Moderate
Cimetidine and Pefloxacin: 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 slow pefloxacin elimination, raising its levels and half-life. Increased fluoroquinolone adverse effects such as CNS effects are possible but this is rarely significant.
What this interaction means in plain words
Cimetidine and Pefloxacin 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; Pefloxacin belongs to Anti Bacterial.
Why it happens
Cimetidine inhibits hepatic oxidative metabolism of pefloxacin, reducing its clearance.
What to do
Monitor for CNS effects and tendon or gastrointestinal adverse effects, and consider lowering the pefloxacin dose in hepatic impairment or the elderly.
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 Pefloxacin
- Pefloxacin + Tizanidine Contraindicated
- Clozapine + Pefloxacin Major
- Duloxetine + Pefloxacin Major
- Pefloxacin + Theophylline Major
- Asenapine + Pefloxacin Moderate
- Caffeine + Pefloxacin Moderate
Frequently asked questions
Can I take Cimetidine with Pefloxacin?
MediHelp rates the interaction as moderate. Cimetidine and Pefloxacin 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 slow pefloxacin elimination, raising its levels and half-life. Increased fluoroquinolone adverse effects such as CNS effects are possible but this is rarely significant.
How serious is the interaction between Cimetidine and Pefloxacin?
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 for CNS effects and tendon or gastrointestinal adverse effects, and consider lowering the pefloxacin dose in hepatic impairment or the elderly.
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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