Drug interactions
Flavoxate + Nortriptyline
Severity: Moderate
Flavoxate and Nortriptyline: 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
Nortriptyline has strong anticholinergic properties, and flavoxate adds antimuscarinic activity. Together they can cause dry mouth, constipation, urinary retention, blurred vision, tachycardia and confusion, particularly in older adults.
What this interaction means in plain words
Flavoxate and Nortriptyline 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.
Flavoxate belongs to Genitourinary; Nortriptyline belongs to Central Nervous System.
Why it happens
Additive antimuscarinic (anticholinergic) pharmacodynamic effects.
What to do
Monitor for anticholinergic toxicity such as urinary retention, constipation and cognitive changes, especially in elderly patients. Reduce the dose or choose a less anticholinergic alternative if symptoms develop.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Flavoxate and Nortriptyline, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Flavoxate
- Clozapine + Flavoxate Major
- Abobotulinumtoxina + Flavoxate Moderate
- Aclidinium + Flavoxate Moderate
- Amantadine + Flavoxate Moderate
- Amitriptyline + Flavoxate Moderate
- Amoxapine + Flavoxate Moderate
Other interactions of Nortriptyline
- Disopyramide + Nortriptyline Contraindicated
- Dofetilide + Nortriptyline Contraindicated
- Dronedarone + Nortriptyline Contraindicated
- Ibutilide + Nortriptyline Contraindicated
- Isocarboxazid + Nortriptyline Contraindicated
- Methylene blue + Nortriptyline Contraindicated
Frequently asked questions
Can I take Flavoxate with Nortriptyline?
MediHelp rates the interaction as moderate. Flavoxate and Nortriptyline 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. Nortriptyline has strong anticholinergic properties, and flavoxate adds antimuscarinic activity. Together they can cause dry mouth, constipation, urinary retention, blurred vision, tachycardia and confusion, particularly in older adults.
How serious is the interaction between Flavoxate and Nortriptyline?
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 toxicity such as urinary retention, constipation and cognitive changes, especially in elderly patients. Reduce the dose or choose a less anticholinergic alternative if symptoms develop.
What other medicines interact with Flavoxate?
MediHelp also lists interactions of Flavoxate with, for example, Clozapine, Abobotulinumtoxina, Aclidinium. The full list is on the Flavoxate page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
