Drug interactions
Benztropine + Flavoxate
Severity: Moderate
Benztropine and Flavoxate: 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
Benztropine is a strong central and peripheral anticholinergic, and adding flavoxate increases the antimuscarinic burden. This can cause urinary retention, constipation, hyperthermia, confusion and cognitive impairment, especially in older patients.
What this interaction means in plain words
Benztropine and Flavoxate 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.
Benztropine belongs to Central Nervous System; Flavoxate belongs to Genitourinary.
Why it happens
Additive antimuscarinic pharmacodynamic effects.
What to do
Monitor for urinary retention, constipation, overheating and confusion. Consider lowering the benztropine dose or choosing a non-anticholinergic alternative.
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 Benztropine
- Benztropine + Memantine-donepezil Major
- Abobotulinumtoxina + Benztropine Moderate
- Amantadine + Benztropine Moderate
- Amitriptyline + Benztropine Moderate
- Amoxapine + Benztropine Moderate
- Atropine iv / + Benztropine Moderate
Frequently asked questions
Can I take Benztropine with Flavoxate?
MediHelp rates the interaction as moderate. Benztropine and Flavoxate 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. Benztropine is a strong central and peripheral anticholinergic, and adding flavoxate increases the antimuscarinic burden. This can cause urinary retention, constipation, hyperthermia, confusion and cognitive impairment, especially in older patients.
How serious is the interaction between Benztropine and Flavoxate?
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 urinary retention, constipation, overheating and confusion. Consider lowering the benztropine dose or choosing a non-anticholinergic alternative.
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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