Drug interactions
Chloral hydrate + Diphenhydramine
Severity: Moderate
Chloral hydrate 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
Chloral hydrate and diphenhydramine are both sedating, so combined use can lead to deeper sedation than expected from either alone. Paediatric sedation protocols and older patients are particularly at risk of excessive drowsiness, confusion or respiratory compromise.
What this interaction means in plain words
Chloral hydrate 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.
Chloral hydrate belongs to Central Nervous System; Diphenhydramine belongs to Respiratory.
Why it happens
Additive CNS depression from a sedative-hypnotic and a sedating first-generation antihistamine.
What to do
Use the lowest effective doses and monitor level of consciousness and respiration, particularly in children and older adults. Avoid other CNS depressants and alcohol.
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 Chloral hydrate
- Calcium / magnesium / potassium / sodium oxybates + Chloral hydrate Contraindicated
- Chloral hydrate + Sodium oxybate Contraindicated
- Alfentanil + Chloral hydrate Major
- Alprazolam + Chloral hydrate Major
- Amobarbital + Chloral hydrate Major
- Belladonna and opium + Chloral hydrate Major
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Chloral hydrate with Diphenhydramine?
MediHelp rates the interaction as moderate. Chloral hydrate 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. Chloral hydrate and diphenhydramine are both sedating, so combined use can lead to deeper sedation than expected from either alone. Paediatric sedation protocols and older patients are particularly at risk of excessive drowsiness, confusion or respiratory compromise.
How serious is the interaction between Chloral hydrate 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: Use the lowest effective doses and monitor level of consciousness and respiration, particularly in children and older adults. Avoid other CNS depressants and alcohol.
What other medicines interact with Chloral hydrate?
MediHelp also lists interactions of Chloral hydrate with, for example, Calcium / magnesium / potassium / sodium oxybates, Sodium oxybate, Alfentanil. The full list is on the Chloral hydrate page.
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