Drug interactions
Butalbital + Diphenhydramine
Severity: Moderate
Butalbital and Diphenhydramine: 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
Butalbital is a barbiturate often given in combination headache products, and diphenhydramine is a sedating antihistamine. The two together increase drowsiness, dizziness and psychomotor impairment, and higher doses may depress breathing. The anticholinergic activity of diphenhydramine can also add to confusion in older adults.
What this interaction means in plain words
Butalbital and Diphenhydramine 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.
Why it happens
Additive central nervous system depression from GABA-A potentiation by the barbiturate and central H1 receptor blockade.
What to do
Monitor for oversedation and reduce doses if drowsiness develops. Counsel patients to avoid driving, alcohol and other sedatives.
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 Diphenhydramine
Frequently asked questions
Can I take Butalbital with Diphenhydramine?
MediHelp rates the interaction as moderate. Butalbital and Diphenhydramine 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. Butalbital is a barbiturate often given in combination headache products, and diphenhydramine is a sedating antihistamine. The two together increase drowsiness, dizziness and psychomotor impairment, and higher doses may depress breathing. The anticholinergic activity of diphenhydramine can also add to confusion in older adults.
How serious is the interaction between Butalbital and Diphenhydramine?
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 oversedation and reduce doses if drowsiness develops. Counsel patients to avoid driving, alcohol and other sedatives.
What other medicines interact with Diphenhydramine?
MediHelp also lists interactions of Diphenhydramine with, for example, Alfentanil, Belladonna and opium, Benzhydrocodone / acetaminophen. The full list is on the Diphenhydramine page.
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