Drug interactions
Iloperidone + Tolterodine
Severity: Moderate
Iloperidone and Tolterodine: 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
Both drugs can prolong the QT interval and both have anticholinergic activity, so combined use may add to QT risk and anticholinergic effects. Iloperidone is also metabolized by CYP2D6 and CYP3A4 and inhibits CYP3A4 weakly, which could modestly raise tolterodine exposure.
What this interaction means in plain words
Iloperidone and Tolterodine 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.
Iloperidone belongs to Central Nervous System; Tolterodine belongs to Genitourinary.
Why it happens
Additive QT prolongation and antimuscarinic effects, with possible minor CYP3A4 inhibition.
What to do
Check baseline ECG and electrolytes and monitor QTc and anticholinergic effects. Avoid in patients with congenital long QT or other QT-prolonging drugs.
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 Tolterodine
Other interactions of Iloperidone
- Iloperidone + Thioridazine Contraindicated
- Alfuzosin + Iloperidone Major
- Amiodarone + Iloperidone Major
- Amisulpride + Iloperidone Major
- Amitriptyline + Iloperidone Major
- Anagrelide + Iloperidone Major
Frequently asked questions
Can I take Iloperidone with Tolterodine?
MediHelp rates the interaction as moderate. Iloperidone and Tolterodine 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. Both drugs can prolong the QT interval and both have anticholinergic activity, so combined use may add to QT risk and anticholinergic effects. Iloperidone is also metabolized by CYP2D6 and CYP3A4 and inhibits CYP3A4 weakly, which could modestly raise tolterodine exposure.
How serious is the interaction between Iloperidone and Tolterodine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check baseline ECG and electrolytes and monitor QTc and anticholinergic effects. Avoid in patients with congenital long QT or other QT-prolonging drugs.
What other medicines interact with Tolterodine?
MediHelp also lists interactions of Tolterodine with, for example, Clarithromycin, Clozapine, Cobicistat. The full list is on the Tolterodine page.
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