Antidepressant prescribing in Gauteng: a public sector drug utilization review

Abstract

Introduction: In South Africa, neuropsychiatric conditions rank third in its contribution to the burden of disease, after AIDS and other infectious diseases. Within the past two decades, the prescribing and subsequent use of antidepressants has become increasingly common, even among children and adolescents. Selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) are widely prescribed by doctors for depression, panic, anxiety, pain and stress disorders. The aim of this study was to conduct a retrospective drug utilisation review on the prescribing of antidepressant drugs in a public health sector outpatient psychiatric clinic and to calculate the drug cost associated with treating depression in this study. The study was conducted on records over a period from January 2011 to September 2014. Methods: Following ethical approval for the study, out-patient prescription records are obtained from the Charlotte Maxeke Johannesburg Academic hospitals psychiatric clinic. This information was then recorded on case report forms and later transferred to a purpose designed spread sheet using Microsoft Excel 2010. Descriptive statistics were used to chart the use of specific antidepressants, the patient demographics and the indications for antidepressant use. Inferential statistics were used to document correlations and drug use. Results: The patient population consisted of 41 male (30.30%) and 94 female patients (69.70%). The population consisted of various ethnicities of which 35.70% (n=48) were Black, 10.30% (n=14) were colored, 13.30% (n=18) were Indian and 40.70% (n=55) were White. The average age of all the patients was 50.16 years (SD= 16.32). Unemployed patients consisted of 50.40% of the patient population whilst only 23.70% of patients were employed and the remainders were pensioners (25.90%). Married patients consisted of 54.81% of the sample whilst single, widowed or divorced patients comprised 45.19%. More than half of the patients had been diagnosed with major depressive disorder or MDD (56.30%). Patients who had also been receiving treatment for a bipolar mood disorder had also been receiving antidepressant therapy (10.37%). Mild depression and MDD with psychotic features were the least present diagnosis (0.74% and 4.44% respectively). Of the total patient population, almost half had been prescribed citalopram as their antidepressant (51.61%), followed by venlafaxine (30.33%) then fluoxetine (18.03%). The patient race has been shown to influence the type of antidepressant chosen (p< 0.0001). There were correlations between the antidepressant chosen and patient race as well as marital status (p<0.0001). As shown in a number of other studies, there are more female patients receiving antidepressant therapy than males. In this study the amount of black male and female patients had been nearly equal with white patients having been composed of more females than males. For coloured and Indian patients, there had been more males than female patients. As expected, the diagnosis of a patient, which had been noted using the ICD 10 codes, had a great influence on the type of antidepressant chosen (p<0.000). The ICD codes used were for the range of depressive disorders from F32 to F42 (Appendix D). .The antidepressant with the most amounts of repeat prescriptions was venlafaxine with an average of 15.13 repeats followed by fluoxetine with 11.77 repeats and citalopram with 10.67 repeats. As shown previously with the total patient population, most males and females had been prescribed citalopram, although it had been prescribed to 12.33% more of the female patients. Fluoxetine was however prescribed to a slightly greater extent to males than females. Fluoxetine was however prescribed to a slightly greater extent to males than females. Citalopram had been the preferred antidepressant in Black, Coloured and White patients (57.14%; 58.30% and 44.00% respectively). Venlafaxine had been prescribed to a much greater extent in the Indian population (55.60%). Fluoxetine had been prescribed more to Black patients than other race group with the same group having venlafaxine prescribed to the least amount of patients. With employed patients, citalopram had been the most frequently prescribed (52.40%) followed by fluoxetine (26.66%) then Venlafaxine (20.94%). In the unemployed group of patients, the second most frequently prescribed drug was venlafaxine (26.96%) followed by fluoxetine (15.19%). The type of antidepressant chosen was shown to be influenced by the marital status of the patient (p= 0.048). The most expensive antidepressant used had been venlafaxine with an average cost per patient of R144.12 per month. Fluoxetine had been the cheapest antidepressant with only a small difference, of between R1.02 and R3.00, as compared to the slightly more expensive citalopram. Conclusion: The data correlates with a number of international DURs and has provided valuable insight into the use of antidepressants in the public sector.