Drug interactions
Cimetidine + Pentazocine
Severity: Moderate
Cimetidine and Pentazocine: 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 may increase pentazocine concentrations and enhance its sedative, respiratory depressant and psychotomimetic effects. The evidence is limited and the effect is generally modest.
What this interaction means in plain words
Cimetidine and Pentazocine 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; Pentazocine belongs to Musculoskeletal.
Why it happens
Cimetidine inhibits hepatic oxidative metabolism of pentazocine.
What to do
Monitor for sedation, confusion and respiratory depression, and lower the pentazocine dose if needed. Consider famotidine as an alternative.
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 Pentazocine
- Calcium / magnesium / potassium / sodium oxybates + Pentazocine Contraindicated
- Olanzapine / samidorphan + Pentazocine Contraindicated
- Pentazocine + Phenelzine Contraindicated
- Pentazocine + Tranylcypromine Contraindicated
- Alfentanil + Pentazocine Major
- Alprazolam + Pentazocine Major
Frequently asked questions
Can I take Cimetidine with Pentazocine?
MediHelp rates the interaction as moderate. Cimetidine and Pentazocine 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 may increase pentazocine concentrations and enhance its sedative, respiratory depressant and psychotomimetic effects. The evidence is limited and the effect is generally modest.
How serious is the interaction between Cimetidine and Pentazocine?
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 sedation, confusion and respiratory depression, and lower the pentazocine dose if needed. Consider famotidine as an alternative.
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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