Updates from the Prescription Review Program

Chloral hydrate should no longer be used as a sedative hypnotic

In the past several years the Office of the Chief Coroner has asked the College to review four patient deaths associated in part with the use of chloral hydrate as a sedative hypnotic.

Standard drug references¹ and published case reports² characterize chloral hydrate as an archaic drug. Tolerance to its hypnotic effect develops rapidly and its therapeutic index is very narrow, especially when combined with alcohol and other sedating drugs. Safer, more effective alternatives exist.

Some physicians appear to underestimate the risk associated with this agent. That may be because it has been used extensively for preoperative sedation in children. The difference, of course, is that preoperative patients are closely monitored.

More generally, physicians are reminded that sedative hypnotics should be used selectively. They are mostly approved and recommended for short-term use only. Sedative hypnotics should not be combined with opioid analgesics. Patients receiving opioids should be advised not to take sleeping medication and vice versa. Abstinence from alcohol is also important.

Many patients overvalue their sleeping pills, ascribing more benefit to them than seems realistic. This is an area of significant challenge in clinical practice. In circumstances where you believe the use of sedative hypnotics is not appropriate, you may wish to bolster your case by citing the unexpected results of a recent study in BMJ Open, which found an association between their use, even occasionally, and patient mortality.³ The difference was not trivial—roughly threefold. Association does not prove cause-and-effect, but much of what we do in medical practice is informed by similar evidence.   

1. Fleming JAE. Psychiatric Disorders: Insomnia. In: Therapeutics choices [Internet]. Ottawa (ON) : Canadian Pharmacists Association; 2012 [cited 6 Sept 2013]. [about 8 p.]. Available from: https://www.cpsbc.ca/library/search-materials/point-of-care-drug-tools by clicking on e-Therapeutics+, then clicking on Therapeutic Choices, and searching for the word Insomnia. Login required.

2. Frankland A, Robinson MJ. Fatal chloral hydrate overdoses: unnecessary tragedies. Can J Psychiatry. 2001 Oct;46(8):763-4.

3. Kripke DF, Langer RD, Kline LE. Hypnotics' association with mortality or cancer: a matched cohort study. BMJ Open. 2012 Feb 27;2(1):e000850. doi: 10.1136/bmjopen-2012-000850.

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