The occurrence of drug related problems in a primary health care setting : a pharmaceutical care approach

Abstract

The worldwide trend in the pharmacy profession is towards pharmaceutical care. According to the latest views the provision of pharmaceutical care by pharmacists is the way forward for the profession in South Africa. Pharmaceutical care is the responsible provision of drug therapy for the purpose of achieving definite outcomes that improve patients quality of life (Hepler & Strand, 1990:539). The provision of pharmaceutical care is the responsibility of health care providers (e.g. a pharmacist, nurse and physician). The roles and functions of the pharmacist in the provision of pharmaceutical care are stipulated in the activities specially pertaining to the Pharmacy Profession and the scope of practice of the pharmacist (Pharmacy Act, 53/1974). The patient's quality of life can be harmed by a drug therapy problem (e.g. adverse effects of a drug, drug interactions, etc.). A drug therapy problem can be defined as any undesirable event experienced by a patient that involves or is suspected to involve drug therapy and that actually or potentially interferes with a desired patient outcome (Cipolle et al., 1998:75). Drug interactions are classified as a drug therapy problem and are a serious problem to consider. Drug interactions can be defined as an altered or modified action of a drug as a result of interaction with another drug. The aim of this study was to investigate the occurrence of drug interactions in a primary health care setting and make recommendations for the identification of drug interactions in health care facilities. Philani Prime Cure® provided the data of primary health care setting used in this study. The data from the seven medi centres were analysed in this study. Ten of the most prescribed drugs [i.e. diphenhydramine, tetracycline (doxycycline and oxytetracycline), co-trimoxazole, hyoscine, theophylline, loperamide, glibenclamide, multivitamin, diclofenac and reserpine] of Philani Prime Cure® medi centres were studied for the identification of drug interactions. A study population of 24991 patients in the seven medi centres were used. There were 131081 medicine items prescribed during the research period (1 January 2000 to 30 June 2000). The ten selected drugs represented 31409 (23.96%) of the total number of medicine items prescribed. The interactions that occurred were drug-drug and drug-age interactions. A total number of 14449 possible drug-drug interactions and a total number of 3604 drug-age interactions occurred with the ten drugs. Interactions were classified according to the significance levels formulated by Tatro (2001:xiv). Level 1 interactions are classified as severe and well documented interactions. Level 2 and 3 interactions are less severe and are also well documented. Level 4 and 5 interactions are classified as minor and unlikely interactions (Tatro, 2001:xiv). For the drug-drug interactions were significance levels are indicated in the literature, level 5 drug-drug interactions occurred the most with the ten selected drugs (n = 1869, 12.94% of all drug-drug interactions). Level 4 interactions (n = 411, 0.31 % ) did not occur as much as level 5 interactions. Level 1 to 3 drug-drug interactions represented 2017 (10.43%) of all drug-drug interactions. Level 1 interactions occurred the most frequent with doxycycline (1.62% of all drug-drug interactions), viz., interaction between doxycyline and antacids. The most frequent level 2 interactions occurred with theophylline (1.32% of all drug-drug interactions), viz., interaction between theophyl line and macrolide antibiotics, and diclofenac (1.94% of all drug-drug interactions), viz., diclofenac and thiazide diuretics. Level 3 interactions occurred the most frequent with multivitamin (3.22% of all drug-drug interactions), viz., interaction between multivitamin and salicylate. During this study another level of significance was created, namely level 6. This level was created to accommodate the identified drug-drug interactions that were not well documented in the literature and needed further investigation. The most drug-age interactions occurred with children and the elderly patients. The most frequent drug interactions occurred with diphenhydramine (19.48% of all drug-age interactions) which were prescribed to patient younger than two years and patients older than 50 years. This study supports the importance of the identification of drug therapy problems in pharmacy practice. Drug interactions were discussed according to the effects of the drugs on each other and the patient quality of life is markedly reduced. The results of this study provide information to the Philani Prime Cure® database to incorporate drug interactions in their protocols. This incorporation of interactions can assist their health care team to identify potential interactions and improve their patient therapeutic outcomes.