Jan Serfontein

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.

Assessment of the appropriateness of antibiotic prescriptions in Lesotho public hospitals: a novel methodology based on principles of antibiotic prescribing

The study primarily aimed at assessing the appropriateness of antibiotic prescriptions in a section of public health institutions in Lesotho using an assessment tool formulated from principles of antibiotic prescribing. Relevant data on procedures of infection diagnosis and prescribed antibiotics were collected from both inpatient and outpatient case reports for a one-month period in five public hospitals in Lesotho. These were analyzed for the appropriateness of the prescribed antibiotics. Prescription appropriateness assessment was based on conformities of prescribed antibiotics to criteria developed from pertinent principles of antibiotic prescribing. Assessed prescriptions, 307 inpatient and 865 outpatient prescriptions in total, were classified into categories of appropriateness based on extents to which they satisfied conditions defined by combinations of criteria in the assessment tool. Antibiotic prescriptions from inpatient and outpatient departments of study site hospitals were categorized into groups of different degrees of appropriateness. A total of 32.2% inpatient prescriptions and 78.4% outpatient prescriptions assessed were appropriately written for the empiric treatment of infections for which bacterial pathogens were considered absolute or possible etiologies. The use of prescription assessment tools based on principles of antibiotic prescribing is a feasible option of assessing the appropriateness of antibiotic prescriptions, particularly in low-income countries where expert panels cannot be formed.

The impact of appropriate antibiotic prescribing on treatment evaluation parameters

The therapeutic impact of inappropriate prescribing of antibiotics is debatable, particularly in situations where infections are treated empirically with multiply prescribed antibiotics. Prescribers may remain under the illusion that such prescriptions are appropriate on the basis of any observed positive treatment outcomes, even though an antibiotic prescribed in such combination therapy may actually be infective against infecting pathogens. This, inevitably, promotes inappropriate antibiotic prescribing. Prescribers may be motivated to make more conscious attempts to prescribe antibiotics appropriately if it is proven that judicious prescribing of antibiotics has positive impacts on treatment outcomes. The objective of this study was to determine the impact of appropriate prescribing of antibiotics on treatment outcomes, days of patient hospitalization and costs related to antibiotic treatment. Observational data on antibiotic treatment were collected for a one-month period from case notes of all inpatients (n=307) and outpatients (n=865) at five government and mission hospitals in Lesotho. Prescriptions were classified into categories of appropriateness based on extents to which antibiotics were prescribed according to principles. Treatment success rates, mean days of hospitalization and costs of antibiotic treatments of inpatients treated with specified prescription categories were determined. Appropriate prescribing of antibiotics for inpatients had positive impacts on treatment outcomes, patients’ days of hospitalization for infections and costs of antibiotic treatments. In outpatient settings, appropriate prescribing of antibiotics failed to show any significant impact on costs of antibiotics. Appropriate prescribing of antibiotics had a positive impact on patients’ recovery and costs of antibiotic treatments in inpatient settings.

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 ..

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.

A cross-sectional analysis of the association between age and gender and prescribed minimum benefit chronic disease list conditions among South Africans with concomitant hypertension, diabetes and dyslipidaemia

BACKGROUND Prescribed Minimum Benefit Chronic Disease List (PMB CDL) conditions are a regulated list of conditions most common to South Africa. OBJECTIVES To investigate the prevalence and association between PMB CDL conditions and age and gender among patients with concomitant hypertension, diabetes and dyslipidaemia. METHODS The study population consisted of patients (n = 17 866) with a prescription containing at least one co-prescribed antilipemics, antihypertensive and antidiabetic (identified using the MIMS Desk Reference). ICD-10 codes on claims for PMB CDL conditions were counted. RESULTS 39.5% of patients had a PMB CDL condition. Women had higher odds for hypothyroidism (OR 6.30, 95% CI; 5.52, 7.19, p < 0.001) and lower odds for coronary artery disease (CAD) (OR 0.63, 95% CI; 0.55, 0.72, p < 0.001) than men. In combination with hypothyroidism the odds for CAD were reversed and strongly increased; 3.54 (95% CI; 2.38, 5.25, p < 0.001). The odds for females having cardiac failure (CF) was insignificant and low (OR 0.87, 95% CI; 0.75, 1.01, p = 0.063); however combined with hypothyroidism, the odds increased to 5.35 (95% CI; 3.52, 8.13, p < 0.001). CONCLUSION Hypothyroidism was an important discriminating factor for co-morbidity in women with concomitant hypertension, diabetes and dyslipidaemia, in particular with cardiovascular disease.

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