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Chloral hydrate Side Effects

Medically reviewed by Last updated on Jun 14, 2023.

Applies to chloral hydrate: capsule liquid filled, suppository, syrup.

Serious side effects of Chloral hydrate

Along with its needed effects, chloral hydrate may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur while taking chloral hydrate:

Less common


Other side effects of Chloral hydrate

Some side effects of chloral hydrate may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

After you stop using this medicine, it may still produce some side effects that need attention. During this period of time, Check with your doctor immediately if you notice the following side effects:

For Healthcare Professionals

Applies to chloral hydrate: compounding powder, oral capsule, oral syrup, rectal suppository.


Frequency not reported: Torsades de pointes, hypotension, ventricular and atrial arrhythmias, depression of myocardial contractility, shortening of refractory period[Ref]


Frequency not reported: Scarlatiniform exanthema, erythematous rash, urticaria, purpura, eczema, bullous lesions, erythema multiforme[Ref]


Frequency not reported: Gastric irritation, nausea, vomiting, abdominal distension, diarrhea, stomach pain, unpleasant taste, flatulence, ileus[Ref]


Frequency not reported: Ketonuria[Ref]


Frequency not reported: Leucopenia, eosinophilia[Ref]


Frequency not reported: Allergic skin reactions, angioedema[Ref]


Frequency not reported: Porphyria[Ref]

Nervous system

Frequency not reported: Headache, unusual/paradoxical excitement, drowsiness, residual sedation/hangover, somnambulism, disorientation, incoherence, delirium, staggering gait, ataxia, lightheadedness, vertigo, dizziness, confusion, coma[Ref]


Frequency not reported: Ptosis, allergic conjunctivitis, keratoconjunctivitis[Ref]


Frequency not reported: Tolerance, hypothermia, malaise, fever, middle ear pressure[Ref]


Frequency not reported: Paranoia, hallucinations, nightmares[Ref]


Frequency not reported: Respiratory depression, laryngeal edema, respiratory obstruction[Ref]


1. Cerner Multum, Inc. UK Summary of Product Characteristics.

2. Canadian Pharmacists Association. e-CPS. 2006.

3. Cerner Multum, Inc. Australian Product Information.

4. PDR Generics. Montvale, NJ: Medical Economics. 1995.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.