Drug interactions
Gemifloxacin + Promethazine
Severity: Moderate
Gemifloxacin and Promethazine: 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
Gemifloxacin can prolong the QT interval and promethazine has some potential to do so as well. Used together they may increase the risk of torsades de pointes, particularly in patients with electrolyte disturbances, bradycardia or structural heart disease.
What this interaction means in plain words
Gemifloxacin and Promethazine 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.
Gemifloxacin belongs to Anti Bacterial; Promethazine belongs to Respiratory.
Why it happens
Additive blockade of cardiac potassium channels leading to QT prolongation.
What to do
Avoid in patients with congenital long QT, uncorrected hypokalemia or hypomagnesemia, or other QT-prolonging drugs. If used, correct electrolytes and consider ECG monitoring.
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 Promethazine
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
- Amiodarone + Promethazine Major
- Amisulpride + Promethazine Major
Other interactions of Gemifloxacin
- Arsenic trioxide + Gemifloxacin Contraindicated
- Dofetilide + Gemifloxacin Contraindicated
- Gemifloxacin + Ibutilide Contraindicated
- Gemifloxacin + Pimozide Contraindicated
- Gemifloxacin + Thioridazine Contraindicated
- Gemifloxacin + Vandetanib Contraindicated
Frequently asked questions
Can I take Gemifloxacin with Promethazine?
MediHelp rates the interaction as moderate. Gemifloxacin and Promethazine 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. Gemifloxacin can prolong the QT interval and promethazine has some potential to do so as well. Used together they may increase the risk of torsades de pointes, particularly in patients with electrolyte disturbances, bradycardia or structural heart disease.
How serious is the interaction between Gemifloxacin and Promethazine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid in patients with congenital long QT, uncorrected hypokalemia or hypomagnesemia, or other QT-prolonging drugs. If used, correct electrolytes and consider ECG monitoring.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Promethazine page.
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