Is there an indication for the use of barbiturate-containing analgesic agents in the treatment of pain? Guidelines for their safe use and withdrawal management. Canadian Pharmacists Association.

OBJECTIVE

To provide medical and pharmaceutical practitioners with information on the effectiveness, safety and risks associated with barbiturate-containing analgesic (BCA) agents and an approach to management of withdrawal from BCAs.

METHODS

The benefits of using BCAs in the treatment of pain (compared with using non-BCAs) were weighed against potential risks. The procedures for discontinuation of BCAs in patients with pain were considered, and evidence showing that BCAs constitute a public health risk was reviewed. The evidence serving as the basis for the clinical guidelines was compiled from a number of sources, including key papers in the field, published and unpublished papers, and reports by Addiction Research Foundation researchers, a MEDLINE search from 1967 to November 1996, and communication with Canadian manufacturers of BCAs.

RESULTS

There is no evidence that there is a clinically important enhancement of analgesic efficacy of BCAs due to the barbiturate constituent. No epidemiological studies on the relative frequency of abuse and dependence, or studies that have analyzed combination product use from a public health and social benefit to risk perspective, have been published to clarify the issues about the nature, extent and seriousness of these problems.

RECOMMENDATIONS

No evidence exists to show a clinically important enhancement of analgesic efficacy of BCAs due to the barbiturate constituents. Because BCAs do not have a therapeutic advantage, there is no clinical reason to choose such a combination product when a simpler and often less expensive analgesic formulation (eg, acetaminophen, acetylsalicylic acid, nonsteroidal anti-inflammatory drug or narcotic) or a more specific anti-migraine drug (eg, dihydroergotamine or sumatriptan) is available. BCAs should be avoided in elderly people and should not be used in children. Extrapolation from published reports on abuse and withdrawal syndrome with these drugs suggests that BCAs have the potential to produce drug dependence and addictive behaviour, especially with regular use. In BCA overdose, the barbiturate component is only one of the clinically significant contributors to any morbidity, but its presence can complicate the management of additive or synergistic toxicities. Therefore, there is no reason to choose a combination product when a simpler product may be a safer alternative by minimizing the potential for addiction and the occurrence of additive side effects or toxicities. It is further recommended that prescribers re-evaluate treatment for patients using BCAs. Recommendations for withdrawal are provided, based on estimated consumption.