Drug interactions
Chlorpromazine + Hyoscyamine
Severity: Moderate
Chlorpromazine 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 and chlorpromazine both block muscarinic receptors, so their combination increases anticholinergic effects such as dry mouth, constipation, urinary retention, tachycardia and confusion. Severe cases can lead to ileus or delirium.
What this interaction means in plain words
Chlorpromazine 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.
Chlorpromazine belongs to Central Nervous System; Hyoscyamine belongs to Genitourinary.
Why it happens
Additive antimuscarinic effects; slowed gastric emptying may modestly reduce chlorpromazine absorption.
What to do
Monitor for anticholinergic toxicity and bowel or bladder function, especially in older adults. Reduce the dose of one agent or switch 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?
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Other interactions of Chlorpromazine
- Chlorpromazine + Dofetilide Contraindicated
- Chlorpromazine + Dronedarone Contraindicated
- Chlorpromazine + Droperidol Contraindicated
- Chlorpromazine + Ibutilide Contraindicated
- Chlorpromazine + Metrizamide Contraindicated
- Chlorpromazine + Panobinostat Contraindicated
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 Chlorpromazine with Hyoscyamine?
MediHelp rates the interaction as moderate. Chlorpromazine 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 and chlorpromazine both block muscarinic receptors, so their combination increases anticholinergic effects such as dry mouth, constipation, urinary retention, tachycardia and confusion. Severe cases can lead to ileus or delirium.
How serious is the interaction between Chlorpromazine 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 and bowel or bladder function, especially in older adults. Reduce the dose of one agent or switch if symptoms develop.
What other medicines interact with Chlorpromazine?
MediHelp also lists interactions of Chlorpromazine with, for example, Dofetilide, Dronedarone, Droperidol. The full list is on the Chlorpromazine page.
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