Prescribing of Methylphenidate to Children and Adolescents in South Africa
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Original Research: Prescribing of methylphenidate to children and adolescents in South Africa Prescribing of methylphenidate to children and adolescents in South Africa: A pharmacoepidemiological investigation Truter I, DCom, BPharm, MSc, PhD Drug Utilization Research Unit, Department of Pharmacy, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa Correspondence to: Prof Ilse Truter, e-mail: [email protected], P O Box 77000, Port Elizabeth, 6031. Tel: +27-41-504-2131 Keywords: attention deficit/hyperactivity disorder (ADHD); drug utilisation; methylphenidate; children; adolescents; pharmacoepidemiology Abstract SA Fam Pract 2009;51(5):413-417 Background: Pharmacoepidemiological studies on ADHD are limited in South Africa. The primary aim was to analyse the prescribing of methylphenidate to patients aged 18 years and younger in the private health care sector. Methods: Data for a one-month period in 2004 were obtained from a large medical aid administrator. Data were retrospectively analysed. The total database contained medicine records for 355 998 patients. Results: A total of 66 450 medicine items were prescribed to 34 733 patients aged 18 years and younger. A total of 1 028 patients received prescriptions for methylphenidate. Nearly 3% of children and adolescents therefore received prescriptions for methylphenidate. The average age of these patients was 10.87 (SD = 2.79) years. Most of these prescriptions (63.14%) were for children between seven and twelve years of age. Most prescriptions were for long-acting methylphenidate in 20 mg, 30 mg and 40 mg capsules (48.87%). The average prescribed daily dose (PDD) for methylphenidate was 19.27 (SD = 11.87) mg. The most popular average PDD was 20 mg (42.63% of all methylphenidate prescriptions). The highest average percentage of methylphenidate prescriptions was in the Western Cape (2.58%), and the lowest in the Northern Cape (0.63%). Conclusions: Numerous claims are being made that methylphenidate is overused or even abused, especially in children of school-going age. Most prescriptions were issued in metropolitan areas in this study, but overuse could not be established. This study was a preliminary study that can lead to more comprehensive studies in future. Peer reviewed. (Submitted:2008-11-13, Accepted:2009-02-06). © SAAFP Background to the study It is generally accepted that ADHD affects 3 to 5% of all school-aged children.2 Epidemiological data on ADHD and methylphenidate prescribing Methylphenidate is the psychostimulant that is most frequently prescribed in the management of Attention Deficit/Hyperactivity Disorder in South Africa is scarce. This study was an attempt to investigate (ADHD) and is also considered to be the first-line medication for the the prescribing of methylphenidate in the nine provinces (different treatment of ADHD.1,2 ADHD is the most common neurodevelopmental geographical regions) of South Africa using the claims database of one of disorder of childhood.1,3 ADHD also has the distinction of being both the three largest medical aid scheme administrators in South Africa. The the most extensively studied childhood mental disorder and the most primary aim of the study was to analyse and compare the prescribing of controversial. methylphenidate to patients aged 18 years and younger in the private Recently, the extensive use or overuse of stimulant medication has been health care sector in South Africa. a widely publicised concern1,4-7 and may be due, in part, to the lack of application of definitive diagnostic criteria and the non-specific nature of Methodology treatments.8 Marked increases in prescription rates of psychostimulants, especially methylphenidate, have also resulted in public health concerns A retrospective, exposure cohort drug utilisation study was conducted. about the frequency and appropriateness with which these medications Data (computerised prescription records) for a one-month period in are prescribed. The increase in prescription can partly be accounted for by 2004 were obtained from one of the three largest medical aid scheme the lengthening of the duration of treatment into adulthood, and increased administrators serving various private medical aid schemes in South treatment among girls. Epidemiologists have also stated that whether a Africa and were analysed. The total database contained medicine records child gets methylphenidate or an equivalent drug depends to a great deal for 355 998 patients who claimed one or more prescription items during on where he or she lives.9 The United States of America consumed 85% the month. The medical aid administrator administers data for a variety of Ritalin® (methylphenidate) produced in 1999, with striking variations between states and also between counties.10 Factors such as economic of medical aids (including closed and open schemes), providing different situation, geographic location and racial background have been shown packages to their members (saving schemes, over-the-counter medicine to play a role in whether a child will receive methylphenidate or not.3,9,11 options and chronic programmes). SA Fam Pract 2009 413 Vol 51 No 5 Original Research: Prescribing of methylphenidate to children and adolescents in South Africa Original Research: Prescribing of methylphenidate to children and adolescents in South Africa All prescription records for methylphenidate were extracted from the Table I: Age distribution of all beneficiaries aged 18 years and younger database and analysed. Records contained information on the age of who filled a prescription in the one-month period the patient, the date of the prescription, the province and the area of AGE (in years) NUMBER OF PATIENTS NUMBER OF ITEMS COST (in rand) residence of the patient, detailed information on the dispensed drug 0 683 1 335 R116 701.98 (name, package size, formulation, strength and quantity) and price. The 1 3 056 6 167 R497 887.61 Monthly Index of Medical Specialities (MIMS)12 and the South African 2 2 844 5 582 R481 328.11 Medicines Formulary13 were used to classify drugs. All costs in the study are indicated in South African rand (R). One US dollar ($1.00) was equal 3 3 172 6 146 R616 876.92 to R6.21, one British pound (£1.00) was equal to R11.26, and one euro 4 2 193 4 230 R384 539.08 (€1.00) was equal to R7.57 on 30 June 2004. Ethical approval for the study 5 1 961 3 783 R367 721.49 was granted by the Faculty of Health Sciences Research, Technology and 6 1 882 3 552 R341 973.31 Innovation Committee of the Nelson Mandela Metropolitan University. 7 1 665 3 069 R325 034.33 The study adhered to ethical principles and patient confidentiality was 8 1 677 3 163 R357 913.52 maintained. No patient in the study could be identified or traced. 9 1 557 2 897 R340 179.61 Limitations of the study were the absence of gender and clinical 10 1 600 2 978 R365 669.13 information in the database. Information about over-the-counter 11 1 431 2 731 R350 968.32 medication that patients used was also not included in the database and was therefore not analysed. Although the study may not necessarily be 12 1 461 2 657 R338 941.60 representative of prescription patterns in the entire private health care 13 1 441 2 733 R308 944.97 sector in South Africa, it does provide insight into the prescription of 14 1 353 2 626 R320 923.86 methylphenidate to patients of 18 years and younger, which can provide 15 1 547 3 052 R393 559.31 baseline information for more comprehensive studies in the future. 16 1 666 3 151 R407 663.71 The focus of this study was only on the prescribing patterns of 17 1 757 3 274 R439 619.15 methylphenidate. It must be noted that a new non-stimulant product for 18 1 787 3 279 R458 747.18 ADHD, atomoxetine, has since been introduced onto the South African TOTAL 34 733 66 450 R7 215 193.19 market. Generic equivalents for methylphenidate have also become available. These products were, however, not yet available on the market The average age of children and adolescents who received one or more at the time of this study and could therefore not be included in the methylphenidate-containing product was 10.87 (SD = 2.79) years. The analysis. youngest patient was 0.67 years, the oldest patient was 18.36 years, and the median age was 10.51 years. Most of the children (63.14%) Results and discussion were between seven and twelve years of age (see Table II). Of the total General prescribing patterns and demographic information of population of children and adolescents in the study, 27.04% (9 391 patient population of the 34 733 patients) were between seven and twelve years of age. This finding is in agreement with that of another South African study15 A total of 66 450 medicine items at a cost of R7 215 193 were prescribed conducted in Tshwane in which it was also found that primary school to 34 733 patients aged 18 years and younger during the one-month children (aged six to twelve years) received the highest percentage period in 2004. The average cost per patient was R207.73 for the month, (61%) of methylphenidate prescriptions. and the average cost per item was R108.58. Nervous system drugs (under which methylphenidate is classified, Table II: Age distribution of patients prescribed methylphenidate Anatomical Therapeutic Chemical (ATC) classification N06BA0413,14 AGE GROUP FREQUENCY accounted for 10.41% of the total number of medicine items and (in years) NUMBER PERCENTAGE 12.85% of the total cost of medicine prescribed to patients of 18 years and younger. Most medicine items (84.34%) were prescribed on an 0–6 50 4.86 acute basis to these children (all therapeutic categories).