Benzodiazepine prescription for patients in opioid maintenance treatment in Norway.

BACKGROUND: Opioid maintained patients report high levels of anxiety, but the use of benzodiazepines among these patients has been associated with negative outcomes such as increased risk of overdose and death and poorer retention in programmes. Previous research has used interview or urine analysis to assess benzodiazepine use. In this study a prescription database was applied.

METHODS: The Norwegian Prescription Database covers all prescriptions for the entire population from 1 January 2004. Benzodiazepine prescriptions to patients receiving methadone (N=1364) or buprenorphine (N=805) in 2004 and 2005 were studied. Type and amount of drugs received were investigated.

RESULTS: Overall 40% of the patients received at least one prescription for a benzodiazepine drug. Oxazepam was the most frequently prescribed drug. Female patients, methadone-maintained patients and patients in the liberal programmes received a prescription more often. Prescribed doses were high and highest in the liberal programmes. Older patients received more hypnotics. Dose of maintenance drug was positively related to amount of anxiolytics prescribed.

CONCLUSIONS: This study showed that more benzodiazepines were prescribed to opioid maintenance treatment patients than previously shown by investigations using interview or urine analysis. The doses prescribed were generally high. In light of the negative outcomes following benzodiazepine use in these patients, Norwegian doctors need to review their prescription practices.