Drug interactions
Chloral hydrate + Thioridazine
Severity: Major
Chloral hydrate and Thioridazine: major interaction.
Last updated Sources: UK SmPC
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
Both cause CNS depression, so combined use can produce deep sedation and hypotension. Thioridazine strongly prolongs the QT interval and chloral hydrate has been associated with arrhythmias, which increases the risk of serious ventricular arrhythmia.
What this interaction means in plain words
Chloral hydrate and Thioridazine 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.
Chloral hydrate belongs to Central Nervous System; Thioridazine belongs to Central Nervous System.
Why it happens
Additive CNS depression plus potential additive cardiac toxicity from thioridazine QT prolongation.
What to do
Avoid the combination where possible and choose a non-QT-prolonging hypnotic. If used, monitor ECG and electrolytes along with level of sedation.
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
- Chloral Hydrate 143mg/5ml Oral Solution - SmPC sections 4.3/4.5 (class statement: antipsychotics; "Concomitant use with antipsychotics, hypnotics, anxiolytics/sedatives, antidepressant agents, centrally acting muscle relaxants, narcotic analgesics, anti-epile") — electronic medicines compendium (UK SmPC)
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 Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Frequently asked questions
Can I take Chloral hydrate with Thioridazine?
MediHelp rates the interaction as major. Chloral hydrate and Thioridazine 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. Both cause CNS depression, so combined use can produce deep sedation and hypotension. Thioridazine strongly prolongs the QT interval and chloral hydrate has been associated with arrhythmias, which increases the risk of serious ventricular arrhythmia.
How serious is the interaction between Chloral hydrate and Thioridazine?
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 the combination where possible and choose a non-QT-prolonging hypnotic. If used, monitor ECG and electrolytes along with level of sedation.
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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