Drug interactions
Flavoxate + Hyoscyamine
Severity: Moderate
Flavoxate and Hyoscyamine: 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
Hyoscyamine is a potent antimuscarinic, and combining it with flavoxate increases anticholinergic effects. Dry mouth, constipation, urinary retention, tachycardia and confusion may occur.
What this interaction means in plain words
Flavoxate and Hyoscyamine 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; Hyoscyamine belongs to Genitourinary.
Why it happens
Additive muscarinic receptor antagonism.
What to do
Monitor for anticholinergic toxicity, especially in older adults, and avoid duplicate antimuscarinic therapy where possible.
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 Flavoxate
- Clozapine + Flavoxate Major
- Abobotulinumtoxina + Flavoxate Moderate
- Aclidinium + Flavoxate Moderate
- Amantadine + Flavoxate Moderate
- Amitriptyline + Flavoxate Moderate
- Amoxapine + Flavoxate Moderate
Other interactions of Hyoscyamine
- Amantadine + Hyoscyamine Moderate
- Amitriptyline + Hyoscyamine Moderate
- Aripiprazole + Hyoscyamine Moderate
- Atropine + Hyoscyamine Moderate
- Benztropine + Hyoscyamine Moderate
- Bethanechol + Hyoscyamine Moderate
Frequently asked questions
Can I take Flavoxate with Hyoscyamine?
MediHelp rates the interaction as moderate. Flavoxate and Hyoscyamine 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. Hyoscyamine is a potent antimuscarinic, and combining it with flavoxate increases anticholinergic effects. Dry mouth, constipation, urinary retention, tachycardia and confusion may occur.
How serious is the interaction between Flavoxate and Hyoscyamine?
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, especially in older adults, and avoid duplicate antimuscarinic therapy where possible.
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.
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