Drug interactions
Hyoscyamine + Perphenazine
Severity: Moderate
Hyoscyamine and Perphenazine: 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 and perphenazine both block muscarinic receptors, so their combination can cause pronounced dry mouth, constipation, urinary retention, tachycardia, blurred vision and confusion. Severe cases may include ileus or heat intolerance.
What this interaction means in plain words
Hyoscyamine and Perphenazine 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 belongs to Genitourinary; Perphenazine belongs to Central Nervous System.
Why it happens
Additive antimuscarinic effects; slowed gut transit may also reduce oral absorption of perphenazine.
What to do
Monitor for anticholinergic toxicity, bowel function and urinary retention, and use the lowest effective doses. Consider alternatives in older or cognitively impaired patients.
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 Perphenazine
- Ibutilide + Perphenazine Contraindicated
- Perphenazine + Pimozide Contraindicated
- Perphenazine + Thioridazine Contraindicated
- Adagrasib + Perphenazine Major
- Alfentanil + Perphenazine Major
- Amiodarone + Perphenazine Major
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 Hyoscyamine with Perphenazine?
MediHelp rates the interaction as moderate. Hyoscyamine and Perphenazine 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 and perphenazine both block muscarinic receptors, so their combination can cause pronounced dry mouth, constipation, urinary retention, tachycardia, blurred vision and confusion. Severe cases may include ileus or heat intolerance.
How serious is the interaction between Hyoscyamine and Perphenazine?
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, bowel function and urinary retention, and use the lowest effective doses. Consider alternatives in older or cognitively impaired patients.
What other medicines interact with Perphenazine?
MediHelp also lists interactions of Perphenazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Perphenazine page.
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