Description and indication for use

Chloral Hydrate is a hypnotic and sedative with CNS depressant properties similar to barbiturates.  The mechanism of action of the drug is not completely known, however the CNS depressant effects of Chloral Hydrate are believed to be mainly due to the active metabolite trichloroethanol.

Chloral Hydrate is rapidly absorbed from the gastrointestinal tract and starts to act within 30 minutes of oral administration.  The duration of action is between four and eight hours. 

Dose

Sedative:     oral/rectal:  8 mg/kg/dose 6 –8 hourly.

Hypnotic:    oral/ rectal:  25 – 50 mg/kg/dose 24 hourly.

NOTE: Overdosage with Chloral Hydrate resembles barbiturate overdose.  Significant toxicity usually develops within two hours of ingestion.  Symptoms include coma, hypotension, hypothermia, respiratory depression and cardiac arrythmias. Miosis, vomiting and muscle flaccidity may also occur.  Oesophageal stricture, gastric necrosis and perforation, and gastrointestinal haemorrhage have also been reported.  Hepatic and renal function may be impaired and may result in transient jaundice and/or albuminuria.  Renal tubular toxicity may occur between two and five days following ingestion.

Death may result from respiratory failure, cardiac arrest or hypotension.

Preparation

Mixture 100 mg/mL.

Route and method of administration

Orally.

May be given rectally; dilute dose with an equal volume of olive oil.

Side effects

May cause nausea, vomiting and diarrhoea due to gastric irritation.

Hyperactivity occurs in 1-2% of patients.

Special considerations

Tolerance to Chloral Hydrate may develop and dependence may occur.

Withdrawal symptoms, similar to those of barbiturates, can occur if Chloral Hydrate is stopped abruptly.  Prolonged administration and abrupt withdrawal of Chloral Hydrate should therefore be avoided to prevent precipitation of withdrawal symptoms.

Contraindications

Use CAUTION in patients with marked hepatic or renal impairment.

Patients with previous history of hypersensivity reaction to Chloral Hydrate itself.

Drug interactions

IV Frusemide – a hypermetabolic state, possibly due to competition for plasma protein binding sites, has been reported in patients given IV Frusemide in up to a 24 hour period after being given Chloral Hydrate.  Symptoms include diaphoreses, flushes, variable blood pressure including hypertension and uneasiness.  Therefore, it may be preferable to use an alternative hypnotic drug in patients who require IV Frusemide.

References

1.        RCH Paediatric Pharmacopoeia, 13th ed. 2002.

2.        RWH Neonatal Pharmacopoeia, 2nd ed. 2005.

3.        MIMS online. (http://www.mimsonline.com.au – accessed 03/10/2013).