Product Evaluation of Carbamazepine 200mg Controlled Release Tablets using an in vitro-in vivo Correlation Simulation Model

Evaluation of the dissolution characteristics of drugs and their bioavailability can be conducted using an in vitro-in vivo correlation model. This can help in assessing the products available in the market for quality. Random testing in post-marketing surveillance would gauge the quality of the drug products. This study involved evaluation of three batches of controlled-release carbamazepine, Tegretol 200mg CR® tablets through dissolution tests from which a dissolution profile and blood concentration-time profile were derived. The in vitro-in vivo correlation simulation model was used to determine the Area Under Curve and Maximum Plasma Concentration and demonstrate bioequivalence of the product batches. The three batches exhibited similarity upon statistical analysis. The results also correspond to the values obtained in literature from bioequivalence studies. In vitro-in vivo correlation can thus be a useful instrument in pharmacovigilance for marketed drug products. Keywords: IVIVC, carbamazepine, bioavailability, pharmacokinetic parameters, dissolutio

Prevalence of Opportunistic Infections in HIV-infected adult patients at Kenyatta National Hospital, Kenya

Background: Opportunistic Infections (OIs) constitute the first manifestation of HIV infection, indicating significant immunodeficiency. OIs remain a leading cause of morbidity and mortality in HIV-infected persons. Since most of OIs are readily treatable and preventable, every effort should be made to facilitated their management. However, there is a need to establish local prevalence of OIs and evaluate their management. This would guide in prioritizing resource and support development of suitable management strategies. Objective: The main objective of this study was to establish the prevalence of HIV-related OIs in adult patients. Methodology: A hospital-based cross-sectional study conducted between July and August 2011 at Kenyatta National Hospital –Comprehensive Care Center (KNH-CCC). Adult patients who were HIV positive and attending outpatient clinic at KNH-CCC were included. Information was collected on patients’ demographics, clinical characteristics and presence of new or active OIs. Data was analyzed using Statistical Package for social Sciences (SPSS) version 11.5. Results: The prevalence of opportunistic infections was 14.1 % (95% CI: 10.7-18.5).  Overall, the most commonly reported bacterial infection was pneumonia (6.4%) whereas pulmonary tuberculosis was reported in 3.6% of patients. Significant association was found between a patients’ current OI status and WHO stage when HIV was diagnosed (AOR= 3.79 [95% CI = 1.43 – 10.03], P=0.007) and duration since HIV diagnosis (AOR 3.89 [95% CI= 1.58-9.59], P=0.003.  90% of patients were prescribed Co-trimoxazole as chemoprophylaxis agent. Conclusion: There was a high prevalence of OIs among the HIV/AIDS patients at KNH-CCC. Bacterial Pneumonia and pulmonary tuberculosis were the most commonly observed OIs. Keyword: Prevalence, Opportunistic-Infections, HIV, Patients

Identification and characterization of potential drug interactions in hypertensive patients in a Kenyan tertiary hospital

Background: Hypertensive patients are particularly at risk of drug-drug interactions resulting from the concomitant use of multiple drugs to control their blood pressure. The presence of comorbidities and advancing age are also likely to contribute to the use of many drugs, further increasing this risk. Drug related problems such as drug interactions in the management of hypertension increase morbidity and mortality but there are limited published data to characterize them especially among the African population. Objective: To identify and characterize potential drug interactions among adult hypertensive patients attending Kenyatta National Hospital. Methods: This was a descriptive cross-sectional study done among 313 adult patients between May to July 2016 at Kenyatta National Hospital. Ethical approval was sought from the institutional review board. Data on patient demographics, clinical characteristics and current prescriptions were extracted from patient records into predesigned data collection forms. Potential drug interactions were identified using an online Drug Interactions Checker. Results: There was female predominance at 60.7% and the mean age of the study population was 55.2 years (SD 15.9).  The mean number of drugs per prescription was 5.93 (SD 2.24). The prevalence of potential drug interactions was 92.7%. There was an average of 3.5 drug interactions per prescription. Majority (79.2%) of the potential drug interactions were categorized as moderate while major and minor interactions accounted for 4.1% and 16.8%, respectively. The most prevalent interacting drug pair was enalapril and furosemide (15.3 %). The most frequent major interaction found was between enalapril and spironolactone, which is associated with hyperkalaemia. Conclusions: There was a high prevalence of potential drug interactions. Prescribers should be encouraged to be vigilant during the management of hypertensive patients to avoid overt drug interactions which may compromise treatment outcomes and increase the health care costs. Keywords: Drug interactions, hypertension, prescriptions, Keny