Norah L. Katende-Kyenda

Prevalence of possible drug-drug interactions between antiretroviral agents in different age groups in a section of the private health care sector setting in South Africa.

Background:  The chronic nature of human immunodeficiency virus (HIV) infection requires lifelong highly active antiretroviral (ARV) therapy (HAART) to continuously suppress HIV‐1 viral replication, thus reducing morbidity and mortality. HAART is restricted by complex dosing, drug–drug interactions (DDIs) and toxicities.

Prevalence of drug-drug interactions of antiretroviral agents in the private health care sector in South Africa.

OBJECTIVES Human immunodeficiency virus (HIV) infection can be effectively treated with highly active antiretroviral therapy (HAART), requiring concomitant administration of three to four different agents, often with a high potential for drug-drug interactions (DDIs). This study aimed to determine the prevalence of possible DDIs between antiretrovirals (ARVs) themselves and other drugs. DESIGN Retrospective drug utilisation study using data from a national medicine claims database for the period 1 January to 31 December 2004. SETTING A section of the private health care sector in South Africa. SUBJECTS All ARV prescriptions (N=43 482) claimed during 2004. The possible DDIs found were classified according to a clinical significance rating described by Tatro (2005) in his book Drug Interaction Facts. RESULTS A total of 5 305 882 medicine items were prescribed; of these, 1.92% (N=101 938) were ARVs. Of the total number of 2 595 254 prescriptions, 1.68% (N=43 482) contained ARVs. A total number of 18 035 DDIs (81 different types) were identified; of these, 83.89% (N=15 130) were DDIs between ARVs and other drugs, while 16.11% (N=2 905) were DDIs between ARVs themselves. Possible DDIs with a clinical significance level of 1 (major, N=17) and 2 (moderate, N=1 436) represented 8.06% (N=1 453) of the total number of identified interactions. CONCLUSIONS Since concomitant use of ARVs and other drugs used to treat HIV complications is increasing, there is a need to understand and anticipate these DDIs and to overcome them by dose adjustments and patient education, so that they are not life threatening to HIV/AIDS patients.

Outcome of the first Medicines Utilization Research in Africa group meeting to promote sustainable and rational medicine use in Africa

The first Medicines Utilization Research in Africa group workshop and symposium brought researchers together from across Africa to improve their knowledge on drug utilization methodologies as well as exchange ideas. As a result, progress was made on drug utilization research and formulating future strategies to enhance the rational use of medicines in Africa. Anti-infectives were the principal theme for the 1-day symposium following the workshops. This included presentations on the inappropriate use of antibiotics as well as ways to address this. Concerns with adverse drug reactions and adherence to anti-retroviral medicines were also discussed, with poor adherence remaining a challenge. There were also concerns with the underutilization of generics. These discussions resulted in a number of agreed activities before the next conference in 2016.

Identification of potential drug–drug interactions between antiretroviral drugs from prescriptions in the private health-care sector in South Africa

The aim of this study was to identify potential drug–drug interactions (DDIs) between antiretroviral drugs (ARVs) and to determine whether prescribed daily doses (PDDs) from prescriptions can be used in the evaluation of these interactions. A quantitative, retrospective drug utilization study was performed on 49,995 and 81,096 ARV prescriptions from a South African pharmacy benefit management company, which were prescribed to 7664 and 10,162 HIV patients for 2005 and 2006, respectively. Potential DDIs identified across different age groups were 778 for 2005 and 1155 for 2006; the majority occurred in patients aged 19 to ≤45 years. The potential DDIs identified between ARVs were all interacting at clinical significance level 2 according to guidelines indicated by Tatro. These results demonstrate that potential DDIs were identified between ARVs mostly in three ARV combinations: Kaletra® (lopinavir/ritonavir) and efavirenz, lopinavir/ritonavir and nevirapine and combinations of indinavir and ritonavir. There is a need for more education on the prescribing protocols for ARVs in the treatment of HIV-infected patients in the private health-care sector in South Africa.

Inapropriateness of antimicrobial prescription in private primary health care settings in South Africa

Extracted from text ... SCIENTIFIC LETTERS 704 Inappropriateness of antimicrobial prescription in private primary health care settings in South Africa N L Katende-Kyenda, M S Lubbe, J H P Serfontein, I Truter To the Editor: Antimicrobials are the most commonly prescribed group of drugs and are overused globally. It has been reported that 20 - 50% of these agents are used inappropriately in developing countries.1 This has resulted in an enormous escalation in the total costs of drugs and high risk for the emergence of antibiotic-resistant bacteria.2 There is a high incidence of infectious diseases in developing countries; these are caused by a multitude ..

Usage of antimicrobial agents in a private primary healthcare setting in South Africa

Objective The aim of this study was to investigate the prescribing of antimicrobials in a private primary healthcare setting in South Africa.

Analysis of possible drug-drug interactions between ritonavir and other antiretrovirals in a section of the private health care sector in South Africa.

ABSTRACT Background The introduction of human immunodeficiency virus (HIV) protease inhibitors (PIs) has led to a dramatic decline in the morbidity and mortality associated with HIV infection. However, the concomitant use of PIs and other antiretrovirals (ARVs) can be complicated by drug-drug interactions (DDIs), adversely affecting levels of PIs. Method A quantitative, retrospective drug utilisation study was performed using data obtained from the medicine claims database of a pharmacy benefit management company during 2004, 2005 and 2006. The possible DDIs found among ARVS themselves were identified using the classification by Tatro. Results The percentage of ARV prescriptions claimed of the total number of medicine items increased from 1.68% (n = 43 482) during 2004 to 3.18% (n = 51 613) during 2005, then to 4.74% (n = 47 085) during 2006. A total of 1 326, 1 863 and 960 possible DDIs were identified among ARVs themselves for 2004, 2005 and 2006 respectively. Of these, ritonavir (unboosted or boosted) presented with the most possible DDIs, accounting for 74.28% (n = 985) for 2004; 67.90% (n = 1 265) for 2005; and 27.50% (n = 264) for 2006. The highest prevalence of DDIs identified was between ritonavir (unboosted) and saquinavir (n = 974, 5) for 2005 and 2006; followed by indinavir (n = 490, 129, 155) for 2004 to 2006; and efavirenz (n = 274) for only 2004; then ritonavir (boosted), co-formulated as lopinavir/ritonavir, and efavirenz (n = 118, 88, 34) for 2004 to 2006; nevirapine (n = 49, 37) for 2004 and 2005; indinavir (n = 9) for 2004; and saquinavir (n = 22) for 2006. Conclusion These findings indicate that concomitant use of PIs such as ritonavir, a potent cytochrome P450(CYP)3A4 enzyme inhibitor, and other ARVs is complicated by possible DDIs and therefore further studies need to be done on the ARV combinations and management of these DDIs.

Effect of prescribed minimum benefits on the prevalence of possible drug‐drug interactions of antiretroviral agents in a section of the private health care sector in South Africa: a 2 year comparative study

Objective The aim of this study was to determine the impact of prescribed minimum benefits (PMBs) after implementation, on the prevalence of possible drug‐drug interactions (DDIs) between antiretrovirals (ARVs) themselves and other drugs on prescriptions claimed in a section of the private health care sector in South Africa.

Determining potential drug-drug interactions between lopinavir/ritonavir and other antiretrovirals and prescribed daily doses in a section of the private health care sector in South Africa

Lopinavir/ritonavir forms part of the antiretroviral therapy for the treatment of human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS). The aim of this non-experimental, quantitative drug-utilization study was to determine and identify potential drug-drug interactions between lopinavir/ritonavir and other antiretrovirals in general practitioners and specialists prescriptions with inappropriate prescribed daily doses. The study was performed on 49,995 (2005), 81,096 (2006) and 88,988 (2007) anti-retroviral (ARV) prescriptions claimed through a pharmacy benefit management company. Of the total 2,638 ARV general practitioners prescriptions and 472 specialist’s prescriptions claimed with potential drug-drug interactions (DDIs), 505 (19.1%) were for general practitioners and 143 (30.3%) for specialists. Potential drug-drug interactions identified between lopinavir/ritonavir and other anti-retrovirals with inappropriate prescribed daily doses accounted for 88.9% (n = 449) for general practitioners and 98.6% (n = 141) for specialist’s prescriptions. The highest percentage of anti-retroviral prescriptions with potential drug-drug interactions were between lopinavir/ritonavir at 1066.4 mg/264 mg and efavirenz at 600 mg average of prescribed daily doses with 61.4% (n = 276) for general practitioners and 38.3% (n = 54) for specialists, prescribed to patients between 19 and 45 years. The recommended standard adult dose for lopivavir/ritonavir is 400 mg/100 mg twice daily or 800 mg/200 mg once daily. The dose prescribed to HIV/AIDS patients in this section of the private health care sector of South Africa was therefore high. It is therefore recommended that more education be given to prescribers and dosage adjustments be done where indicated.

Antiretroviral prescriptions with potential drug-drug interactions from general practitioners and specialists.

1with about 5 million of them living in South Africa (SA). The World Health Organization estimated that 4.7 million people living in sub-Saharan Africa urgently needed antiretroviral therapy (ART). In that year SA implemented prescribed minimum benefits (PMBs) for HIV/AIDS in the private health care sector. 2 Despite the increased availability and affordability of ART in SA, only 60 000 people were receiving ART through medical aid schemes by mid-2005. 3 Antiretrovirals (ARVs) have transformed HIV/AIDS into a chronic disorder that can be managed effectively. The right of all HIVinfected adults and children to receive standard care is endorsed by the SA HIV Clinicians Society (SAHIVCS), 4 with ART guidelines recommending different combinations. The rapid approval of new drugs resulted in an increased risk of prescribing errors, dispensing of incorrect dosages/dose frequencies, and incorrect reporting of drugs by the patient to the prescribers, 5 all leading to treatment failure. Drug-drug interactions (DDIs) are an under-recognised consequence of medication prescription errors, resulting in significant health care costs. 6 Since DDIs determine positive and negative consequences of treatment for HIV-infected patients, recommendations to avoid some drug combinations and to adjust dosages of some co-administered drugs were formulated by both the SAHIVCS 4