Prescribing patterns of antidepressants with known off–label indications among adults
Le Roux, Jan Daniël
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“Off-label use” is defined as the use of medicine for indications other than recommended or registered for, e.g. the prescribing of a particular active substance for a patient younger than the substance is recommended or indicated for, or different formulations or dosages of a substance (Ekins-Daukes et al., 2004:349; Stedman’s medical dictionary, 2006). Off-label prescribing is common, and fluctuates by physician, patient and drug (Eguale et al., 2012:781). Drug classes most commonly prescribed off-label include anti-asthmatic, cardiovascular drugs and antidepressants. Lee et al. (2012:140) found that 9 out of 10 antidepressants prescribed were associated with unapproved usage of antidepressants. An antidepressant can be defined as a substance that prevents or relieves depression or depressive episodes (Mosby, 2009:115). There is paucity of information on the off-label prescribing practices of antidepressants in the South African private health sector. According to Eguale et al. (2012:781), the paucity of information on off-label prescribing practices may be, in part, ascribed to the difficulty in the establishment of reasons for treatment. The objective of this study was to determine the prescribing patterns of antidepressants as well as to identify off-label prescribing of antidepressants among adults in a section of the private health sector of South Africa by using a medicine claims database. A quantitative and observational, descriptive cross-sectional design was followed in this study. Data for a period of a year, from January to December 2010 were obtained for analysis. The data set consisted of medicine claims for a total number of 1 220 289 patients, containing a total of 8 515 428 prescriptions and 20 527 777 medicine items. The study population (patients receiving antidepressants 18 years and older) accounted for 14.8% (n = 1 220 289) of the total data set. The average age of patients receiving antidepressants was 56.1 ± 16.6 (median = 56.2) (Inter quartile range = 43.3–68.1). Results of the study showed that antidepressant prescriptions accounted for 8.3% (n = 8 515 428) of all prescriptions claimed during 2010. A total 3.5 % (n = 20 527 777) of antidepressants were claimed during the study period. Using the DU90% method it was established that the majority of antidepressant medicine items were prescribed by general practitioners (i.e. 75.7%, n = 702 285) and psychiatrists (14.9%, n = 702 285). Almost 72% (n = 702 885) of antidepressant medicine items claimed for the study population were for women. The most prescribed antidepressants (based on the DU90%) were amitriptyline (20.6%, n = 702 885), citalopram (19.2%), escitalopram (14.6%), fluoxetine (11.7%), venlafaxine (5.7%), paroxetine (5.2%), duloxetine (4.4%), sertraline (3.8%), bupropion (3.1%) and mirtazapine (2.6%). Amitriptyline accounted for 82.4% of off-label prescriptions (n = 2 635), whereas escitalopram and fluoxetine accounted for 4.2% and 3.8%, respectively. The tricyclic antidepressants (TCAs) were mostly prescribed off-label for migraine, headache and sleep disorders. The off-label prescribing of selective serotonin re-uptake inhibitors (SSRIs) included menopause, schizophrenia and headache. The off-label indicated prescriptions of the serotonin and noradrenaline re-uptake inhibitors (SNRIs) were mostly for schizophrenia and other anxiety disorders. Mirtazapine, a serotonin modulator/tetracyclic antidepressant, was mostly prescribed off-label for anxiety disorders. Off-label prescriptions for bupropion, a noradrenaline and dopamine re-uptake inhibitor mainly included other anxiety disorders and attention deficit hyperactivity disorder (ADHD). Furthermore, the prescribed daily dose (PDD) of each active antidepressant for all off-label indications was determined. In conclusion: This study investigated the off-label prescribing patterns of antidepressants among adults a section of the private health sector of a South Africa, using a large medicine claims database. Recommendations for future research were made.
- Health Sciences