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Volume 492: debated on Wednesday 20 May 2009

To ask the Secretary of State for Health what guidance his Department issues on the safe half-life of a drug intended for use as a sleeping tablet; what the half-life of nitrazepam is; and how many nitrazepam prescription items were dispensed in 2008. (276004)

Nitrazepam belongs to the class of medicines known as benzodiazepines. It is licensed for the short-term treatment of severe insomnia which is considered to be disabling or subjecting the individual to unacceptable distress, where daytime sedation is acceptable.

Nitrazepam acts in 30 to 60 minutes to produce sleep lasting six to eight hours. The half-life is, on average, 24 hours but depending on the individual can range from 16 to 38 hours. As a result nitrazepam has a prolonged action and may give rise to residual effects the following day, and repeated doses tend to be cumulative. Shorter acting agents are therefore preferable for the majority of patients requiring treatment for insomnia.

The half-life of a drug intended for use as a sleeping tablet is only one of many factors that influences the safe use of a medicine. Information to aid the safe use of nitrapezam is provided in the product information which consists of the Summary of Product Characteristics for healthcare professionals and the Patient Information Leaflet. These are available on the internet at

Additional prescribing advice is provided in the British National Formulary, which is sent to all doctors within the national health service.

Guidance on the safe use of benzodiazepines has been issued by the Department on a number of occasions; the focus of this advice has been on the need for restriction of use to short-term only. In the case of nitrazepam the recommended treatment period varies from a few days to two weeks with a maximum of four weeks including the tapering off process.

Based on information obtained from the Prescription Cost Analysis database it has been estimated that 1,172,799 prescription items of nitrazepam were dispensed in the community in England during 2008. This figure does not include items which may have been dispensed within a hospital setting.