Use of psychotropic drugs and analgesics among users of antiobesity drugs--a population based study.

Objective: The aim of the present study was to investigate to what extent patients using prescription antiobesity drugs (orlistat, sibutramine and rimonabant) concomitantly or concurrently used psychotropic drugs and analgesics and the association between this drug use and the patients' gender and age. An additional aim was to investigate the sequence of drug therapy among users of both antiobesity drugs and antidepressants or antipsychotics, respectively.

Methods: Data were retrieved from the Norwegian Prescription Database (NorPD). All patients who had an antiobesity drug (ATC code A08A) dispensed from a Norwegian pharmacy between January 2004 and December 2007 were included in the study.

Results: One in four patients using antiobesity drugs had at least on one occasion used a psychotropic drug concomitantly. The most commonly used psychotropic drugs were anxiolytics/hypnotics/sedatives (17.7%) and antidepressants (14.7%). Analgesics were used by 36.2%. A significantly higher percentage of women used anxiolytics/hypnotics/sedatives (18.8% vs. 14.0%, p < 0.0005), antidepressants (16.1% vs. 9.5%, p < 0.0005), antipsychotics (4.0% vs. 2.9%, p < 0.0005) and analgesics (37.8% vs. 30.5%, p < 0.0005) concomitantly with antiobesity drugs when compared to men. One out of ten patients using sibutramine had at least on one occasion used an interacting drug concomitantly.

Conclusions: Use of psychotropic drugs and analgesics among patients using antiobesity drugs is extensive, especially among women. Clinicians prescribing sibutramine should be more aware of drug interactions with other prescribed drugs. There is still insufficient information on psychiatric disorders among these patients.