Antidepressant usage by South African children and adolescents : a drug utilisation review
Van Rooyen, Cornelius Jacobus
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This study set out to review and analyse aspects of antidepressant prescribing in children and adolescents in a section of the private health care sector of South Africa. The research was conducted in two phases, namely a literature review and an empirical investigation. The aim of the literature review was to provide background to the study by conceptualising antidepressants. The empirical review followed a retrospective, descriptive, observational design. The data employed in the study was obtained from the medicine claims database of a South African Pharmaceutical Benefit Management (PBM) company. The study population consisted of 3 611 children and adolescents receiving ≥1 antidepressants from 1 January 2010 to 31 December 2010. Basic descriptive statistics, such as frequency, prevalence, average, weighted average, standard deviation, weighted standard deviation, median, effect sizes, prescribed daily dosages and DU95% methodology were used to characterise the study sample, and were calculated using the Statistical Analysis System SAS® for Windows 9.3® program. The data were used to determine the prescribing patterns of antidepressants with regard to age, gender, geographic area, type of prescriber, the comparison of prescribed daily dosages vs. recommended daily dosages, and the prevalence of potential drug-drug interactions. Potential drug-drug interactions were identified and compiled by using various interaction compendia, whereas recommended daily dosages were identified by cross-referencing various dosage compendia. The study population consisted of 1 850 girls and 1 761 boys. The mean age of girls was 13.7 ± 3.9 years, vs. 12.3 ± 3.8 years for boys (d = 0.4). A total of 11 735 prescriptions containing 12 272 antidepressants were documented in 2010. Results of the study furthermore showed that the average number of prescriptions claimed per patient increased with age, from an average of 1.0 ± 0.28 among those up to the age of 2 years, to an average of 3.4 ± 3.21 among those 16 to 18 years of age. Prescribing with regard to age groups differed, rising gradually from birth and peaking at middle childhood for boys, whereas antidepressant use in girls increased from birth up to 6 years of age, reaching a plateau and increases again from age 13 and onward. Approximately 25% (n = 12 272) of antidepressants prescribed were either not indicated in children, or the dosages were deemed too high. More than 50% (n = 12 272) of antidepressants prescribed were in the Gauteng province. The SSRIs (selective serotonin re-uptake inhibitors) and the TCAs (tricyclic antidepressants) were the most prescribed antidepressants in both gender groups. The male-to-female ratio for the selective serotonin re-uptake inhibitors was 0.9, compared to 1.2 for the tricyclic antidepressants. The top three antidepressants prescribed were imipramine (21.8%), citalopram (15.3%) and escitalopram (14.7%, n = 12 272). Potential DDIs were observed on 284 (2.4%) (n = 11 743) prescriptions. The drug pairs with potential drug-drug interactions prescribed most, were imipramine with methylphenidate [43 cases (15.1%)] and valproic acid [38 cases (13.4%)], and followed by methylphenidate in combination with fluoxetine and sertraline [both documenting 32 cases (11.3%), respectively. The TCAs accounted for 182 (64.1%) cases of possible DDIs (drug-drug interactions), whereas combination therapy of SSRIs and TCAs accounted for 21.4% of potential DDIs. In conclusion, this study determined that there were a number of differences with regard to antidepressant prescribing in children and adolescents. Recommendations for future studies were made.
- Health Sciences