New guidelines for barbiturate-containing analgesics: Don't start, and help stop!

William McLean

CMAJ 2000;163(4):414-5

Although these products are effective because they contain an analgesic, they also contain a barbiturate for which there is no evidence of therapeutic benefit, either alone or in addition to the analgesics, and they may be addictive. Physicians who manage patients with chronic pain are perhaps all too familiar with this latter problem and the clinical difficulty of distinguishing continuing pain needing treatment and dependence on a compound that contains a known addictive substance. The abuse potential of barbiturate-containing analgesics has not been well studied, and questions remain as to whether they cause dependence in regular use at normal doses. There are, however, many reports of illicit trade and abuse of these substances. An additional concern is the potential for addiction to codeine, which is often included in these medications.¹

Discontinuing the use of these medications may not be easy. Patients and physicians are familiar with anecdotal reports of withdrawal, and many physicians are reluctant to discontinue these medications because they fear their patients may experience modest to severe withdrawal effects.

Because of the paucity of literature available to evaluate the effectiveness of barbiturate-containing analgesics, the risks of habituation and the dangers of discontinuing their use, a joint panel of the Canadian Pharmacists Association and the CMA has recently issued a set of guidelines² on the safe use of these medications, including withdrawal management (panel members are listed at the end of the article). The recommendations may be summarized as follows:

• There is no evidence that the barbiturate component of these analgesics provides any health benefit, and it may cause other health problems, mainly dependence and addiction.
• Patients already taking these medications should be switched to safer products. The guidelines provide specific recommendations for this process. For example, in patients taking a barbiturate-containing compound 7–12 times per day, the guidelines recommend that the dose be gradually tapered off over 4–6 weeks, accompanied by counselling concerning the patient's expectations of the process and what to do if withdrawal symptoms occur. Close support during this period is critical. For patients taking more than 12 doses per day, in whom abrupt withdrawal symptoms might occur, referral to an addiction specialist is recommended.

No doubt there are some physicians and pharmacists who have been concerned about these products and have made efforts, unsuccessfully, to discontinue their use. Furthermore, some patients will suffer some withdrawal effects (including headache), and this will only reinforce the patient's illusion, and perhaps the physician's, that the medication is effective. In such cases, the physician, working in concert with the patient and pharmacist, should find the guidelines helpful.

Despite the paucity of evidence, but after a reasonable and careful assessment of the risks and benefits, other countries such as the United Kingdom, France, Germany and Australia have already removed barbiturate-containing analgesics from the market. Canada might do well to consider such action. It is recommended in the guidelines of the Canadian Pharmacists Association and the CMA that physicians not start new patients on these compounds and that they collaborate with their patients and pharmacists to stop the use of these substances and to switch to other treatments if needed.

Competing interests: Dr. McLean received income for the Pharmaceutical Care Data Analysis Project, which was funded by an unrestricted grant from Sabex Inc. in 1999. He received income for a number of small research projects in 1998/99 for the Health Outcome Pharmacies Cooperative, which received unrestricted grants from Novopharm Limited and Apotex Inc. Dr. McLean was Chair of the Canadian Pharmacists Association–CMA Joint Advisory Panel on Barbiturate-Containing Analgesics, which was supported in part by an unrestricted grant from Glaxo Wellcome Inc.

Members of the CPhA–CMA Joint Advisory Panel on Barbiturate-Containing Analgesics: Dr. William McLean (chair), Ottawa, Ont.; Ms. Ann Boucher, Ottawa, Ont.; Dr. Michael Brennan, London, Ont; Dr. Anne Holbrook, Hamilton, Ont.; Mr. Robert Orser, Ottawa, Ont.; Dr. John Peachey, Ottawa, Ont.; Dr. Edward Sellers, Toronto, Ont.

Correspondence to: Dr. William McLean, Pharmaceutical Outcomes Research Unit, Ottawa Hospital – General Campus, 501 Smyth Rd., Ottawa ON K1H 8L6; fax 613 737-8891; wmclean@ottawahospital.on.ca

1.	Sellers EM, Hoornweg K, Busto UE, Romach MK. Risk of drug dependence and abuse posed by barbiturate-containing analgesics. Can J Clin Pharmacol 1999;6:18-25. [MEDLINE]
2.	McLean W, Boucher A, Brennan M, Holbrook A, Orser R, Peachey J, et al. Is there indication for the use of barbiturate-containing analgesics (BCAs) in the treatment of pain? Guidelines for their safe use and withdrawal management. Can J Clin Pharmacol. In press.

© 2000 Canadian Medical Association or its licensors