Importation trends in antibiotics for veterinary use in Rwanda: A retrospective study between 2019 and 2021.

Estimating antibiotic consumption in animals is fundamental to guiding decision-making and research on controlling the emergence and spread of antibiotic-resistant bacteria in humans, animals, and the environment. This study aimed to establish importation trends of antibiotics for veterinary use in Rwanda between 2019 and 2021. Data was collected from the Rwanda Food and Drugs Authority's database. Quantities of imported antibiotic active ingredients were computed using the information extracted from the issued import licenses. These quantities were subsequently adjusted per animal biomass. In total, 35,291.4 kg of antibiotics were imported into Rwanda between 2019 and 2021, with an annual mean of 11,763.8 ± 1,486.9 kg. The adjustment of imported quantities of antibiotics per animal biomass revealed that 29.1 mg/kg, 24.3 mg/kg, and 30.3 mg/kg were imported in 2019, 2020, and 2021 respectively. A slight but not statistically significant decline in antibiotic importation was noted in 2020 (p-value = 0.547). Most of the imported antibiotics were indicated to be used in food-producing animals (35,253.8 kg or 99.9% of the imported antibiotics). Tetracyclines (17,768.6 kg or 50.3%), followed by sulfonamides (7,865.0 kg or 22.3%) and aminoglycosides (4,071.1 kg or 11.5%), were the most imported antibiotics over the studied period. It was noted that 78.9% of the imported antibiotics were categorized as highly important antimicrobials for human medicine. This study established a generalized overview of the importation of antibiotics for veterinary use in Rwanda. These results can serve as guidance for the control of antibiotic misuse. They can be used to make a correlation between antibiotic importation, antibiotic consumption, and the occurrence of antibiotic resistance in the country.

Efficacy of Single-Dose Praziquantel for the Treatment of Schistosoma mansoni Infections among School Children in Rwanda.

Preventive chemotherapy with single-dose praziquantel is the WHO-recommended intervention strategy to eliminate schistosomiasis as a public health problem in endemic countries. Surveillance of drugs used in mass drug administration (MDA) programs is recommended to evaluate its effectiveness in reducing transmissions. After a decade-long implementation of a school-based MDA program in Rwanda, we conducted efficacy surveillance of single-dose praziquantel MDA against S. mansoni infection. Two weeks before MDA, stool examinations were performed to screen MDA-eligible school children (n = 4998) for S. mansoni infection using the Kato-Katz technique, and 265 (6.5%) children tested positive for the infection. All children received praziquantel and albendazole as preventive chemotherapy through the MDA campaign. Infected children were enrolled and followed for efficacy monitoring, and stool examination was repeated after three weeks post-MDA (n = 188). Before treatment, 173 (92%) had a light infection, and 15 (8%) had a moderate infection intensity. The primary and secondary outcomes were parasitological cure and egg reduction rates at three weeks post-treatment. The overall cure and egg reduction rates for S. mansoni infection were 97.9% (95% CI = 94.6-99.4) and 97.02%, respectively. Among the 173 children with light infection intensity, 170 (98.3%, 95% CI = 95.0-99.6) were cured, and among the 15 children who had moderate infection intensity, 14 (93.3%) were cured. No significant association between cure rate and pre-treatment infection intensity was observed. We conclude that single-dose praziquantel is efficacious against light-to-moderate S. mansoni infection. Preventive chemotherapy with praziquantel effectively reduces schistosome reservoirs and transmission among school-age children.

Efficacy of Single-Dose Albendazole for the Treatment of Soil-Transmitted Helminthic Infections among School Children in Rwanda-A Prospective Cohort Study.

Mass drug administration (MDA) of single-dose albendazole to all at-risk populations as preventive chemotherapy (deworming) is recommended by WHO to halt transmission of soil-transmitted helminth (STH) in endemic countries. We assessed the effectiveness of single-dose albendazole against STH infection in the western province of Rwanda, where STH prevalence remains high despite the implementation of preventive chemotherapy for over a decade. Two weeks before the scheduled MDA, 4998 school children (5-15 years old) were screened for STH infections (Ascaris lumbricoides, Trichuris trichiura, and hookworm), and 1526 children who tested positive for at least one type of STH parasite were enrolled and received single-dose albendazole (400 mg) through MDA. A follow-up stool exam was performed at three weeks post-treatment using Kato-Katz. Efficacy was assessed by cure rate (CR), defined as the proportion of children who became egg-free, and egg reduction rates (ERRs) at three weeks post-treatment. The CR and ERR for hookworms (CR = 96.7%, ERR = 97.4%) was above, and for Ascaris lumbricoides (CR = 95.1%, ERR = 94.6%) was borderline compared with the WHO efficacy threshold (CR and ERR ≥ 95%). However, the CR and ERR for T. trichiura (CR = 17.6% ERR = 40.3%) were below the WHO threshold for efficacy (CR and ERR ≥ 50%). Having moderate-to-heavy infection intensity and coinfection with another type of STH parasites were independent risk factors for lower CR and ERR against Trichirus trichiura (p < 0.001). Single-dose albendazole used in the MDA program is efficacious for the treatment and control for hookworms and Ascaris lumbricoides infections but not effective for Trichirus trichiura. An alternative treatment regimen is urgently needed to prevent, control, and eliminate STH as a public health problem.

Effect of pharmacogenetic variations on praziquantel plasma concentration and safety outcomes among school children in Rwanda.

School-based mass drug administration (MDA) of Praziquantel (PZQ) is the global intervention strategy for elimination of schistosomiasis. Genetic variations in drug metabolizing enzymes and transporter proteins influences drug exposure and treatment outcomes, but data on PZQ pharmacokinetics and safety outcomes are scarce. We investigated the effect of pharmacogenetics variations on PZQ plasma concentrations and safety outcomes among 462 Rwandan schoolchildren who received single dose PZQ and albendazole in MDA. Genotyping for common functional variant alleles CYP3A4*1B, CYP3A5 (*3, *6, *7), CYP2C19 (*2, *3, *17), CYP2C9 (*2, *3) and CYP2J2*7 were done. Plasma concentration of PZQ, cis-4-OH-PZQ and trans-4-OH-PZQ were measured using LC/MS/MS. Active safety monitoring was done on days 1, 2, and 7 post-MDA. CYP2C9 and CYP2C19 genotypes were significantly associated with PZQ plasma concentrations and its cis- and trans-4-OH-PZQ/PZQ metabolic ratios (MR). CYP2C9*2 and CYP2C9*3 carriers had significantly higher PZQ concentration (p = 0.02), lower trans-4-OH-PZQ/PZQ (p < 0.001), and cis-4-OH-PZQ/PZQ (p = 0.02) MR. CYP2C19 (*2, *3) carriers had significantly higher plasma PZQ concentration than CYP2C19 *1/*1 and CYP2C19 *17 carriers (*1/*17 or *17/*17) (p < 0.001). CYP3A4 was significantly associated with cis-4-OH-PZQ MR (p = 0.04). Lower cis-4-OH-PZQ/PZQ MR (p < 0.0001) was a predictor of MDA-associated adverse events, but no significant association with genotypes were found. In conclusion, CYP2C9 and CYP2C19 genotypes significantly influence the plasma PZQ concentration and its MR. Lower cis-4-OH-PZQ/PZQ MR is significant predictor of adverse events following MDA.

Effects of Enzyme Induction and Polymorphism on the Pharmacokinetics of Isoniazid and Rifampin in Tuberculosis/HIV Patients.

Tuberculosis is the most common cause of death in HIV-infected individuals. Rifampin and isoniazid are the backbones of the current first-line antitubercular therapy. The aim of the present study was to describe the time-dependent pharmacokinetics and pharmacogenetics of rifampin and isoniazid and to quantitatively evaluate the drug-drug interaction between rifampin and isoniazid in patients coinfected with HIV. Plasma concentrations of isoniazid, acetyl-isoniazid, isonicotinic acid, rifampin, and 25-desacetylrifampin from 40 HIV therapy-naive patients were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after the first dose and at steady state of antitubercular therapy. Patients were genotyped for determination of acetylator status and CYP2C19 phenotype. Nonlinear mixed-effects models were developed to describe the pharmacokinetic data. The model estimated an autoinduction of both rifampin bioavailability (0.5-fold) and clearance (2.3-fold). 25-Desacetylrifampin clearance was 2.1-fold higher at steady state than after the first dose. Additionally, ultrarapid CYP2C19 metabolizers had a 2-fold-higher rifampin clearance at steady state than intermediate or extensive metabolizers. An induction of isonicotinic acid formation from isoniazid dependent on total rifampin dose was estimated. Simulations indicated a 30% lower isoniazid exposure at steady state during administration of standard rifampin doses than isoniazid exposure in noninduced individuals. Rifampin exposure was correlated with CYP2C19 polymorphism, and rifampin administration may increase exposure to toxic metabolites by isoniazid in patients. Both findings may influence the risk of treatment failure, resistance development, and toxicity and require further investigation, especially with regard to ongoing high-dose rifampin trials.

Safety of Praziquantel and Albendazole Coadministration for the Control and Elimination of Schistosomiasis and Soil-Transmitted Helminths Among Children in Rwanda: An Active Surveillance Study.

INTRODUCTION: School-based preventive chemotherapy (Deworming) with praziquantel and albendazole to control and eliminate schistosomiasis and soil-transmitted helminths as public health problems is recommended by the World Health Organization (WHO). Safety monitoring during mass drug administration (MDA) is imperative but data from sub-Saharan Africa are scarce. OBJECTIVE: The aim of this active safety surveillance study was to identify the incidence, type, severity, and risk factors for adverse events (AEs) following mass administration of praziquantel and albendazole. METHODS: Overall, 8037 school children aged 5-15 years in Rwanda were enrolled. Baseline sociodemographic, medical history and any pre-existing clinical symptoms were recorded. Participants received a single dose of praziquantel and albendazole during MDA. AEs were actively monitored on days 1, 2, and 7 post MDA. RESULTS: Overall, 3196 AEs were reported by 1658 children; 91.3%, 8.4%, and 0.3% of the AEs were mild, moderate, and severe, respectively, and most resolved within 3 days. Headache (21%), dizziness or fainting (15.2 %), nausea (12.8%) and stomach pain (12.2%) were the most common AEs. The overall cumulative incidence of experiencing at least one type of AE was 20.6% (95% confidence interval [CI] 19.7-21.5%), being significantly higher (p < 0.001) in children with pre-MDA clinical events (27.5%, 95% CI 25.4-29.6%) than those without (18.7%, 95% CI 17.7-19.7%). Females, older age, having pre-MDA events, types of food taken before MDA and taking two or more praziquantel tablets were significant predictors of AEs. CONCLUSIONS: Praziquantel and albendazole MDA is safe and well-tolerated; however, one in five children experience transient mild to moderate, and in few cases severe, AEs. The incidence of AEs varies significantly between sex and age groups. Pharmacovigilance in the MDA program is recommended for timely detection and management of AEs.

Changes in the Proteome in the Development of Chronic Human Papillomavirus Infection-A Prospective Study in HIV Positive and HIV Negative Rwandan Women.

BACKGROUND: Effects on the proteome when a high risk (HR)-HPV infection occurs, when it is cleared and when it becomes chronic were investigated. Moreover, biomarker panels that could identify cervical risk lesions were assessed. METHODS: Cytology, HPV screening and proteomics were performed on cervical samples from Rwandan HIV+ and HIV- women at baseline, at 9 months, at 18 months and at 24 months. Biological pathways were identified using the String database. RESULTS: The most significantly affected pathway when an incident HR-HPV infection occurred was neutrophil degranulation, and vesicle-mediated transport was the most significantly affected pathway when an HR-HPV infection was cleared; protein insertion into membrane in chronic HR-HPV lesions and in lesions where HR-HPVs were cleared were compared; and cellular catabolic process in high-grade lesions was compared to that in negative lesions. A four-biomarker panel (EIF1; BLOC1S5; LIMCH1; SGTA) was identified, which was able to distinguish chronic HR-HPV lesions from cleared HR-HPV/negative lesions (sensitivity 100% and specificity 91%). Another four-biomarker panel (ERH; IGKV2-30; TMEM97; DNAJA4) was identified, which was able to distinguish high-grade lesions from low-grade/negative lesions (sensitivity 100% and specificity 81%). CONCLUSIONS: We have identified the biological pathways triggered in HR-HPV infection, when HR-HPV becomes chronic and when cervical risk lesions develop. Moreover, we have identified potential biomarkers that may help to identify women with cervical risk lesions.

Effect of efavirenz-based ART on the pharmacokinetics of rifampicin and its primary metabolite in patients coinfected with TB and HIV.

OBJECTIVES: To evaluate the effects of concomitant efavirenz-based ART and genetic polymorphism on the variability in rifampicin and 25-desacetylrifampicin pharmacokinetics. PATIENTS AND METHODS: Plasma concentrations of rifampicin and 25-desacetylrifampicin from 63 patients coinfected with TB and HIV were analysed by LC-MS/MS followed by non-linear mixed-effects modelling. Patients were genotyped for SLCO1B1 (463 C>A, 388 A>G, 11187 G>A, rs4149015, 521 T>C and 1436 G>C) and SLCO1B3 (334 T>G). RESULTS: One-compartment disposition models described the observations adequately. The oral clearances of rifampicin and 25-desacetylrifampicin were 140% and 110% higher, respectively, in patients on concomitant efavirenz-based ART. Rifampicin bioavailability was also lower in patients on concomitant ART. Further, although not included in the final model, a lower relative bioavailability in carriers of WT SLCO1B3 334 T>G compared with carriers of mutations in the genotype was estimated. CONCLUSIONS: The results presented indicate both pre-systemic and systemic induction by efavirenz-based ART affecting rifampicin pharmacokinetics. The described drug-drug interaction has a clinical impact on rifampicin exposure prior to steady state and may impact the early bactericidal activity in patients on efavirenz-based ART.

Factors Affecting the Pharmacokinetics of Pyrazinamide and Its Metabolites in Patients Coinfected with HIV and Implications for Individualized Dosing.

Pyrazinamide is a first-line drug used in the treatment of tuberculosis. High exposure to pyrazinamide and its metabolites may result in hepatotoxicity, whereas low exposure to pyrazinamide has been correlated with treatment failure of first-line antitubercular therapy. The aim of this study was to describe the pharmacokinetics and metabolism of pyrazinamide in patients coinfected with tuberculosis and HIV. We further aimed to identify demographic and clinical factors which affect the pharmacokinetics of pyrazinamide and its metabolites in order to suggest individualized dosing regimens. Plasma concentrations of pyrazinamide, pyrazinoic acid, and 5-hydroxypyrazinamide from 63 Rwandan patients coinfected with tuberculosis and HIV were determined by liquid chromatography-tandem mass spectrometry followed by nonlinear mixed-effects modeling. Females had a close to 50% higher relative pyrazinamide bioavailability compared to males. The distribution volumes of pyrazinamide and both metabolites were lower in patients on concomitant efavirenz-based HIV therapy. Furthermore, there was a linear relationship between serum creatinine and oral clearance of pyrazinoic acid. Simulations indicated that increasing doses from 25 mg/kg of body weight to 35 mg/kg and 50 mg/kg in females and males, respectively, would result in adequate exposure with regard to suggested thresholds and increase probability of target attainment to >0.9 for a MIC of 25 mg/liter. Further, lowering the dose by 40% in patients with high serum creatinine would prevent accumulation of toxic metabolites. Individualized dosing is proposed to decrease variability in exposure to pyrazinamide and its metabolites. Reducing the variability in exposure may lower the risk of treatment failure and resistance development.

Comparative Assessment of the Pharmacovigilance Systems within the Neglected Tropical Diseases Programs in East Africa-Ethiopia, Kenya, Rwanda, and Tanzania.

Monitoring the safety of medicines used in public health programs (PHPs), including the neglected tropical diseases (NTD) program, is a WHO recommendation, and requires a well-established and robust pharmacovigilance system. The objective of this study was to assess the pharmacovigilance systems within the NTD programs in Ethiopia, Kenya, Rwanda, and Tanzania. The East African Community Harmonized Pharmacovigilance Indicators tool for PHPs was used to interview the staff of the national NTD programs. Data on four components, (i) systems, structures, and stakeholder coordination; (ii) data management and signal generation; (iii) risk assessment and evaluation; and (iv) risk management and communication, were collected and analyzed. The NTD programs in the four countries had a strategic master plan, with pharmacovigilance components and mechanisms to disseminate pharmacovigilance information. However, zero individual case safety reports were received in the last 12 months (2017/2018). There was either limited or no collaboration between the NTD programs and their respective national pharmacovigilance centers. None of the NTD programs had a specific budget for pharmacovigilance. The NTD program in all four countries had some safety monitoring elements. However, key elements, such as the reporting of adverse events, collaboration with national pharmacovigilance centers, and budget for pharmacovigilance activity, were limited/missing.

Prevalence, Intensity, and Correlates of Soil-Transmitted Helminth Infections among School Children after a Decade of Preventive Chemotherapy in Western Rwanda.

Preventive chemotherapy (PC) is a WHO-recommended core intervention measures to eliminate Soil-Transmitted Helminths (STH) as a public health problem by 2020, defined as a reduction in prevalence to <1% of moderate or high-intensity infection. We conducted a cross-sectional study to investigate the prevalence, intensity, and correlates of STH after a decade of PC in Rwanda. A total of 4998 school children (5-15 years old) from four districts along Lake Kivu in the western province were screened for STH using Kato-Katz. The overall prevalence of Soil-transmitted helminths among school children was 77.7% (range between districts = 54% to 92%). Trichirus trichiura was the most common STH (66.8%, range between districts = 23% to 88.2%), followed by Ascaris lumbricoides (49.9%, range between district = 28.5% to 63.3%) and hookworms (1.9%, range between districts = 0.6% to 2.9%). The prevalence of single, double and of triple parasite coinfection were 48.6%, 50.3%, and 1.1%, respectively. The overall prevalence of moderate or high-intensity infection for Trichirus trichiura and Ascaris lumbricoides was 7.1% and 13.9, respectively. Multivariate logistic regression model revealed that male sex, district, stunting, and schistosomiasis coinfection as significant predictors of STH infection. Despite a decade of PC implementation, STH remain a significant public health problem in Rwanda.

Model-Based Assessment of Variability in Isoniazid Pharmacokinetics and Metabolism in Patients Co-Infected With Tuberculosis and HIV: Implications for a Novel Dosing Strategy.

Tuberculosis is the most common cause of death in HIV-infected patients. Isoniazid is used as a first-line drug to treat tuberculosis infection. However, variability in isoniazid pharmacokinetics can result in hepatotoxicity or treatment failure. Determination of clinical factors affecting isoniazid pharmacokinetics and metabolic pathways in HIV co-infected patients is therefore critical. Plasma levels of isoniazid, acetyl-isoniazid, and isonicotinic acid from 63 patients co-infected with tuberculosis and HIV were analyzed by liquid chromatography with tandem mass spectrometry followed by nonlinear mixed-effects modeling. Patients were genotyped to determine acetylator status. Patients were either on concomitant efavirenz-based antiretroviral therapy or HIV treatment naïve. Clearances of isoniazid were 1.3-fold and 2.3-fold higher in intermediate and rapid acetylators, respectively, compared with slow acetylators. Patients on concomitant efavirenz-based antiretroviral therapy had 64% and 80% higher population predicted clearances of acetyl-isoniazid and isonicotinic acid, respectively, compared with patients who were HIV treatment naïve. Both sex and CD4 cell count affected the bioavailability of isoniazid. Variability in isoniazid exposure could be reduced by dose adaptions based on acetylator type and sex in addition to the currently used weight bands. A novel dosing strategy that has the potential to reduce isoniazid-related toxicity and treatment failure is presented.

Comparative Assessment of the National Pharmacovigilance Systems in East Africa: Ethiopia, Kenya, Rwanda and Tanzania.

INTRODUCTION: The increased access to medicinal products in Africa is not well-matched with the pharmacovigilance capacity to monitor drug safety. The objective of this study was to assess the functionality and identify the strengths and limitations of the national pharmacovigilance systems in Ethiopia, Kenya, Rwanda, and Tanzania, and compare these systems. METHODS: Legal and statutory documents governing the pharmacovigilance systems of each participating country were examined by assessors prior to on-site review. The staff of the pharmacovigilance unit of the National Medicines Regulatory Authorities (NMRAs) were interviewed using the East African Community Harmonized Pharmacovigilance Indicators tool, supplemented with indicators from the World Health Organization (WHO) Global Benchmarking Tool. Responses were recorded, and data were analyzed. RESULTS: The pharmacovigilance systems were supported by law and regulations in line with international standards. Standard operating procedures for receiving, processing, and communicating suspected adverse event reports were in place, but reporting of suspected medicine-related harm from stakeholders was inadequate in all countries. The number of Individual Case Safety Reports (ICSRs) received by NMRAs in Kenya, Ethiopia, and Tanzania (mainland) were 35.0, 6.7, and 4.1 per million inhabitants, respectively, in the last calendar year. At the time of assessment, Rwanda did not have an operational system. Overall, ≤ 1% of the total number of health facilities per country submitted ICSRs. Only Kenya and Tanzania had a designated budget for pharmacovigilance activities and an electronic ICSR reporting system. The national pharmacovigilance systems in all four countries did not have access to data on drug utilization. CONCLUSIONS: The national pharmacovigilance systems in the four East African countries have policy and legal frameworks defined by law and regulation to conduct pharmacovigilance activities. However, the four national pharmacovigilance systems are at different levels of capacity and performance with respect to conducting pharmacovigilance activities. Targeted interventions are needed to strengthen the pharmacovigilance systems to enable evidence-based decision making for patient safety.

Population Pharmacokinetics and Pharmacogenetics of Ethambutol in Adult Patients Coinfected with Tuberculosis and HIV.

This study aimed to characterize the population pharmacokinetics and pharmacogenetics of ethambutol in tuberculosis-HIV-coinfected adult patients. Ethambutol plasma concentrations, determined by liquid chromatography-tandem mass spectrometry, in 63 patients receiving ethambutol as part of rifampin-based fixed-dose combination therapy for tuberculosis were analyzed using nonlinear mixed-effects modeling. A one-compartment disposition model with first-order elimination and four transit compartments prior to first-order absorption was found to adequately describe the concentration-time profiles of ethambutol in plasma. Body weight was implemented as an allometric function on the clearance and volume parameters. Estimates of oral clearance and volume of distribution were 77.4 liters/h and 76.2 liters, respectively. A G/A mutation with regard to CYP1A2 2159 G>A was associated with a 50% reduction in relative bioavailability. Simulations revealed that doses of 30 mg/kg of body weight and 50 mg/kg for G/G and G/A carriers, respectively, would result in clinically adequate exposure. The results presented here suggest that CYP1A2 polymorphism affects ethambutol exposure in this population and that current treatment guidelines may result in underexposure in patients coinfected with tuberculosis and HIV. Based on simulations, a dose increase from15 to 20 mg/kg to 30 mg/kg is suggested. However, the 50-mg/kg dose required to reach therapeutic exposure in G/A carriers may be inappropriate due to the dose-dependent toxicity of ethambutol. Additional studies are required to further investigate CYP450 polymorphism effects on ethambutol pharmacokinetics.

Simultaneous quantification of four first line antitubercular drugs and metabolites in human plasma by hydrophilic interaction chromatography and tandem mass spectrometry.

Co-infection of tuberculosis in HIV-patients is a major health concern worldwide and especially so in Sub-Saharan Africa. To enhance the study of potential drug-drug interactions when simultaneously treating the two infections, a liquid chromatography tandem mass spectrometry method was developed for the quantitation of the four first line anti-tuberculosis drugs isoniazid, rifampicin, pyrazinamide, ethambutol and four of their major metabolites in human plasma. Analytes were extracted from 200 µL of plasma using a sequential liquid-liquid extraction with ethyl acetate at neutral and acidic pH. The combined extracts were analyzed by liquid chromatography with mass spectrometric detection in a multiple reaction monitoring mode. The chromatographic separation was performed on a hydrophilic interaction column using a stepwise gradient with two mobile phases consisting of water with 0.3% formic acid and methanol with 0.3% formic acid, respectively. The total run time of each analysis was 4 min. The lower limit of quantification applied was 40 ng/mL for ethambutol, acetylisoniazid and 25-desacetylrifampicin, 60 ng/mL for 5-hydroxypyrazinamide, 80 ng/mL for isoniazid and isonicotinic acid, 200 ng/mL for rifampicin and 320 ng/mL for pyrazinamide. The method was validated according to US Food and Drug Administration guidance. The method exhibited adequate accuracy (87.1-114.9%), precision (CV < 12.8%) and specificity. Recovery and matrix effect were consistent (CV < 11.9%). The extracted samples were stable in the autosampler at 8 °C for up to 24 h as well as after three freeze-thaw cycles (recovery > 86.3%). The method has been shown to be robust for the analysis of the stated drugs and metabolites in human plasma obtained from 73 patients receiving these four first line anti-tuberculosis drugs.

The role of genetic polymorphisms in cytochrome P450 and effects of tuberculosis co-treatment on the predictive value of CYP2B6 SNPs and on efavirenz plasma levels in adult HIV patients.

Efavirenz (EFV) exhibits interindividual pharmacokinetic variability caused by differences in cytochrome P450 (CYP) expression. Most tuberculosis (TB) drugs interact with the CYP metabolizing enzymes, while the clinical validity of genotyping in predicting EFV plasma levels in Rwandan subjects is not known. We investigated in patients co-infected with human immunodeficiency virus (HIV) and TB recruited in Rwanda the effects of 10 SNPs in five drug-metabolizing enzymes on EFV plasma levels and treatment response when patients are treated with EFV-containing therapy alone (n=28) and when combined with rifampicin-based TB treatment (n=62), and the validity of genotyping for CYP2B6 single nucleotide polymorphisms in predicting supra-therapeutic EFV levels. There was a significant difference between CYP1A2 -739T/G and T/T genotypes when patients were treated with EFV-containing therapy combined with rifampicin-based TB treatment, but not when EFV-containing therapy was alone. CYP2B6 516T/T genotype was associated with high EFV levels compared to other CYP2B6 516G>T genotypes in the presence and in the absence of rifampicin-based TB treatment. Predictive factors of EFV plasma levels in the presence of rifampicin-based TB treatment were CYP2A6 1093G>A, CYP2B6 516G>T, and CYP2B6 983T>C accounting for 27%, 43%, and 29% of the total variance in EFV levels, respectively. There was a high positive predictive value (PPV) (100%) for CYP2B6 516T/T and 983T/T genotypes in predicting EFV plasma levels above the therapeutic range, but this PPV decreased in the presence of rifampicin-based TB treatment. Rifampicin-based TB treatment was also shown to affect EFV plasma levels significantly, but did not affect the significant reduction of HIV-RNA copies. These results indicate that genotyping for CYP2B6 SNPs could be used as a tool in predicting supra-therapeutic EFV plasma levels, which could minimize adverse drug events.

A rapid and selective HPLC-UV method for the quantitation of efavirenz in plasma from patients on concurrent HIV/AIDS and tuberculosis treatments.

Owing to heterogeneity in therapeutic response, efavirenz is of research and clinical interest. There is a need to quantitate it using noncostly and selective methods. A method for efavirenz quantitation in plasma containing HIV and tuberculosis drugs was developed. Chromatographic separation was carried out using a C18 column. The mobile phase consisted of 0.1% formic acid and acetonitrile, and was pumped at a flow rate of 0.3 mL/min. Efavirenz and ritonavir (internal standard) were monitored at 247 nm. Plasma proteins were precipitated by centrifugation. The analysis time was 6 min. The response was linear (r = 0.9997). The accuracy ranged between 98 and 115% (intraday) and between 99 and 117% (interday). The precision ranged from 1.670 to 4.087% (intraday) and from 3.447 to 13.347% (interday). Recovery ranged from 98 to 132%. Stability ranged between 99 and 123%. The selectivity was proven by analysis of drugs used for the management of HIV/AIDS and tuberculosis. Plasma sample analysis showed an efavirenz retention time of 5.57 min and a peak plasma concentration of 2.4 µg/mL occurring at 2 h. This method is rapid and selective, and thus suitable for monitoring efavirenz in patients with HIV/AIDS alone or co-infected with tuberculosis in a less resourced setting.

Prices of antihypertensive medicines in sub-Saharan Africa and alignment to WHO's model list of essential medicines.

OBJECTIVE: To investigate compliance of National Essential Medicines Lists (NEMLs) with the WHO Essential Medicines List (WHO/EML) in 2007 and to compare prices of antihypertensive drugs in and between 13 sub-Saharan African countries. METHODOLOGY: Data on NEMLs and drug prices were collected from 65 public and 65 private pharmacies (five of each per country). Prices were compared with the International Drug Price Indicator Guide (IDPIG). The cost of drug treatment within a country was calculated using defined daily doses (DDD) and between countries using DDD prices adjusted for purchasing power parity-based gross domestic product per capita. RESULTS: All surveyed countries had a NEML. However, none of these lists were in complete alignment with the 2007 WHO/EML, and 38% had not been updated in the last 5 years. Surveyed medicines were cheaper when on the NEMLs; they were also cheaper in public than in private pharmacies. Prices varied greatly per medicine. A large majority of the public prices were higher than those indicated by the IDPIG. Overall, hydrochlorothiazide is the cheapest drug. CONCLUSION: There are substantial differences in NEML composition between the 13 countries. The proportion of NEMLs not regularly updated was double the global United Nations estimates. Prices of WHO/EML-advised drugs differ greatly between drugs and for each drug within and between countries. In general, the use of drugs on the NEML improves financial accessibility, and these drugs should be prescribed preferentially.

A strategy to improve skills in pharmaceutical supply management in East Africa: the regional technical resource collaboration for pharmaceutical management.

BACKGROUND: International initiatives such as the Global Fund to Fight AIDS, Tuberculosis and Malaria, the President's Emergency Plan for AIDS Relief and the President's Malaria Initiative have significantly increased availability and access to medicines in some parts of the developing world. Despite this, however, skills remain limited on quantifying needs for medications and ordering, receiving and storing medications appropriately; recording medications inventories accurately; distributing medications for use appropriately; and advising patients on how to use medications appropriately. The Regional Technical Resource Collaboration for Pharmaceutical Management (RTRC) has been established to help address the problem of skills shortage in pharmaceutical management in East Africa. METHODS: The initiative brings together academic institutions from four East African countries to participate in skills-building activities in pharmaceutical supply management. The initiative targeted the institutions' ability to conduct assessments of pharmaceutical supply management systems and to develop and implement effective skills-building programmes for pharmaceutical supply chain management. RESULTS: Over a two-year period, the RTRC succeeded in conducting assessments of pharmaceutical supply management systems and practices in Kenya, Rwanda, Tanzania and Uganda. In 2006, the RTRC participated in a materials-development workshop in Kampala, Uganda, and contributed to the development of comprehensive HIV/AIDS pharmaceutical management training materials; these materials are now widely available in all four countries. In Tanzania and Uganda the RTRC has been involved with the training of health care workers in HIV/AIDS pharmaceutical management. In Kenya, Tanzania and Uganda the RTRC has been conducting operations research to find solutions to their countries' skills-shortage problems. Some of the interventions tested include applying and evaluating the effectiveness of a novel skills-building approach for pharmaceutical supply management. CONCLUSION: Nurturing collaboration between regional institutions in resource-limited countries to build in-country skills in pharmaceutical supply management appears to be an effective intervention. Support from local programmes and technical assistance from organizations and institutions with the necessary expertise is critical for success, particularly at inception. The skills acquired by local institutions can be incorporated into both pre-service and in-service teaching curricula. This ensures long-term availability of skills in-country. The ability of trained institutions to mobilize their own resources for skills-building activities is crucial for the success and sustainability of these programmes.