Drug interactions
Promethazine + Tiotropium-olodaterol
Severity: Moderate
Promethazine and Tiotropium-olodaterol: 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
Promethazine is strongly anticholinergic and sedating, so it can add to tiotropium antimuscarinic effects, causing dry mouth, urinary retention, constipation and blurred vision. It also has some QT-prolonging potential that olodaterol may add to.
What this interaction means in plain words
Promethazine and Tiotropium-olodaterol 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.
Promethazine belongs to Respiratory; Tiotropium-olodaterol belongs to Respiratory.
Why it happens
Additive antimuscarinic activity and possible additive QT effects.
What to do
Monitor for anticholinergic adverse effects, especially in elderly patients or those with prostatic hypertrophy or glaucoma. Reduce or stop promethazine if effects are troublesome.
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 Tiotropium-olodaterol
Other interactions of Promethazine
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
- Amiodarone + Promethazine Major
- Amisulpride + Promethazine Major
Frequently asked questions
Can I take Promethazine with Tiotropium-olodaterol?
MediHelp rates the interaction as moderate. Promethazine and Tiotropium-olodaterol 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. Promethazine is strongly anticholinergic and sedating, so it can add to tiotropium antimuscarinic effects, causing dry mouth, urinary retention, constipation and blurred vision. It also has some QT-prolonging potential that olodaterol may add to.
How serious is the interaction between Promethazine and Tiotropium-olodaterol?
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 anticholinergic adverse effects, especially in elderly patients or those with prostatic hypertrophy or glaucoma. Reduce or stop promethazine if effects are troublesome.
What other medicines interact with Tiotropium-olodaterol?
MediHelp also lists interactions of Tiotropium-olodaterol with, for example, Amisulpride, Arformoterol, Arsenic trioxide. The full list is on the Tiotropium-olodaterol page.
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