Drug interactions
Chlorpheniramine + Pentobarbital
Severity: Major
Chlorpheniramine and Pentobarbital: major interaction.
Last updated Sources: US FDA label
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
Pentobarbital is a barbiturate with strong sedative effects. Combined with chlorpheniramine, CNS depression can be enhanced, leading to marked drowsiness, impaired coordination and potentially respiratory depression.
What this interaction means in plain words
Chlorpheniramine and Pentobarbital can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Additive CNS depression from GABA-A potentiation and H1 antagonism.
What to do
Avoid concurrent use where possible; if needed, reduce doses and monitor sedation and respiration. Warn against alcohol and driving.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Chlorpheniramine
Frequently asked questions
Can I take Chlorpheniramine with Pentobarbital?
MediHelp rates the interaction as major. Chlorpheniramine and Pentobarbital can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Pentobarbital is a barbiturate with strong sedative effects. Combined with chlorpheniramine, CNS depression can be enhanced, leading to marked drowsiness, impaired coordination and potentially respiratory depression.
How serious is the interaction between Chlorpheniramine and Pentobarbital?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid concurrent use where possible; if needed, reduce doses and monitor sedation and respiration. Warn against alcohol and driving.
What other medicines interact with Chlorpheniramine?
MediHelp also lists interactions of Chlorpheniramine with, for example, Belladonna and opium, Benzhydrocodone / acetaminophen, Brexanolone. The full list is on the Chlorpheniramine page.
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