Anti-TB drug concentrations and drug-associated toxicities among TB/HIV-coinfected patients.

Background: Toxicities due to anti-TB treatment frequently occur among TB/HIV-coinfected patients. Objectives: To determine the association between anti-TB drug concentrations and the occurrence of hepatotoxicity and peripheral neuropathy among TB/HIV-coinfected patients. Methods: TB/HIV-coinfected patients were started on standard dose anti-TB treatment according to WHO guidelines. Anti-TB drug concentrations were measured using HPLC 1, 2 and 4 h after drug intake at 2, 8 and 24 weeks following initiation of TB treatment. Participants were assessed for hepatotoxicity using Division of AIDS toxicity tables and for peripheral neuropathy using clinical assessment of tendon reflexes, vibration sensation or symptoms. Cox regression was used to determine the association between toxicities and drug concentrations. Results: Of the 268 patients enrolled, 58% were male with a median age of 34 years. Participants with no hepatotoxicity or mild, moderate and severe hepatotoxicity had a median C max of 6.57 (IQR 4.83-9.41) µg/mL, 7.39 (IQR 5.10-10.20) µg/mL, 7.00 (IQR 6.05-10.95) µg/mL and 3.86 (IQR 2.81-14.24) µg/mL, respectively. There was no difference in the median C max of rifampicin among those who had hepatotoxicity and those who did not ( P = 0.322). There was no difference in the isoniazid median C max among those who had peripheral neuropathy 2.34 (1.52-3.23) µg/mL and those who did not 2.21 (1.45-3.11) µg/mL ( P = 0.49). Conclusions: There was no association between rifampicin concentrations and hepatotoxicity or isoniazid concentrations and peripheral neuropathy among TB/HIV-coinfected patients.

Prevalence and type of drug-drug interactions involving ART in patients attending a specialist HIV outpatient clinic in Kampala, Uganda.

OBJECTIVES: Scale-up of HIV services in sub-Saharan Africa has rapidly increased, necessitating evaluation of medication safety in these settings. Drug-drug interactions (DDIs) involving antiretrovirals (ARVs) in sub-Saharan Africa are poorly characterized. We evaluated the prevalence and type of ARV DDIs in Ugandan outpatients and identified the patients most at risk. METHODS: A total of 2000 consecutive patients receiving ARVs at the Infectious Diseases Institute, Kampala were studied. The most recent prescription for each patient was screened for clinically significant DDIs using www.hiv-druginteractions.org. Univariable and multivariable logistic regression were used to identify risk factors for DDIs. A screening tool was developed using significant risk factors and tested in a further 500 patients. RESULTS: Clinically significant DDIs were observed in 374 (18.7%) patients, with a total of 514 DDIs observed. Only 0.2% of DDIs involved a contraindicated combination. Comedications commonly associated with DDIs were antibiotics (4.8% of 2000 patients), anthelmintics (2.2%) and antifungals (3.5%). Patient age, gender, CD4 count and weight did not affect risk of DDIs. In multivariable analysis, the patient factors that independently increased risk of DDIs were two or more comedications (P < 0.0001), a PI-containing ARV regimen (P < 0.0001), use of an anti-infective (P < 0.0001) and WHO clinical stage 3-4 (P = 0.04). A scoring system based on having at least two of these risk factors identified between 75% and 90% of DDIs in a validation cohort. CONCLUSIONS: Significant ARV DDIs occur at similar rates in resource-limited settings and developed countries; however, the comedications frequently causing DDIs differ. Development of tools that are relevant to particular settings should be a priority to assist with prevention and management of DDIs.

The Effect of Gene Variants on Levonorgestrel Pharmacokinetics When Combined With Antiretroviral Therapy Containing Efavirenz or Nevirapine.

Reduced levonorgestrel concentrations from the levonorgestrel contraceptive implant was previously seen when given concomitantly with efavirenz. We sought to assess whether single nucleotide polymorphisms (SNPs) in genes involved in efavirenz and nevirapine metabolism were linked to these changes in levonorgestrel concentration. SNPs in CYP2B6, CYP2A6, NR1I2, and NR1I3 were analyzed. Associations of participant demographics and genotype with levonorgestrel pharmacokinetics were evaluated in HIV-positive women using the levonorgestrel implant plus efavirenz- or nevirapine-based antiretroviral therapy (ART), in comparison to ART-naïve women using multivariate linear regression. Efavirenz group: CYP2B6 516G>T was associated with lower levonorgestrel log10 Cmax and log10 AUC. CYP2B6 15582C>T was associated with lower log10 AUC. Nevirapine group: CYP2B6 516G>T was associated with higher log10 Cmax and lower log10 Cmin . Pharmacogenetic variations influenced subdermal levonorgestrel pharmacokinetics in HIV-positive women, indicating that the magnitude of the interaction with non-nucleoside reverse transcriptase inhibitors (NNRTIs) is influenced by host genetics.

Causes and outcome of hospitalization among HIV-infected adults receiving antiretroviral therapy in Mulago hospital, Uganda.

BACKGROUND: Cohorts describing cause specific mortality in HIV-infected patients initiating antiretroviral therapy (ART) operate on an outpatient basis. Hospitalized patients represent the spectrum and burden of severe morbidity and mortality in patients on ART. OBJECTIVE: To determine the causes and outcomes of hospitalization among adults receiving ART. METHODS: A prospective cohort study. We enrolled 201 participants (50% female) with median (IQR) age and CD4 count of 34 (28-40) years and 91(29-211) cells/uL respectively. RESULTS: The most frequent causes of hospitalization were tuberculosis (TB) (37, 18%), cryptococcal meningitis (22, 11%), zidovudine (AZT) - associated anemia (19, 10%), sepsis (10, 5%) and Kaposi's sarcoma (10, 5%). Forty two patients (21%) died: 10 (24%) had TB, 8 (19%) had cryptococcal meningitis and 5 (12%) had sepsis, 9 (21%) had undiagnosed neurological syndromes while 10 (24%) had other illnesses. Predictors of death included low Karnofsky performance score of < 40 (OR, 21.1; CI 1.43- 31.6) and age >34 years (OR, 7.65; CI 1.09- 53.8). CONCLUSIONS: Opportunistic infections, malignancy and AZT-associated anemia contributed to most hospitalizations and mortality. It is important to intensify prevention, screening, and treatment for these opportunistic diseases and early ART initiation in HIV-infected patients. Tenofovir-based regimens, unless contraindicated should be scaled up to replace AZT-based regimens as first line ART drugs.

Health care related factors associated with severe malaria in children in Kampala, Uganda.

BACKGROUND: Severe malaria is responsible for the high load of malaria mortality. It is not clearly understood why some malaria episodes progress to severe malaria. OBJECTIVE: To determine factors associated with severe malaria in children aged 6 months to 5 years living in Kampala. METHODS: Over a 6-month period, 100 children with severe malaria were matched by age and place of residence with 100 children with non-severe malaria. We collected health care information from care takers. RESULTS: Mean duration of illness before getting antimalarial treatment was shorter for controls than cases (8 hours vs. 20 hours, p 0.015). Children with severe malaria were less likely to have been treated with sulphadoxine-pyrimethamine in the preceding 2 weeks (OR 0.2, 95% CI 0.04-0.85, p 0.016). Odds of severe malaria were higher in those who reported lack of protective measures (mosquito coils (OR = 20.63, 95% CI 1.5-283.3, p=0.02 and insecticide sprays OR 10.93, 95% CI 1.13-105.64, p=0.03), although few reported their use. CONCLUSIONS: Early anti-malarial treatment and use of barriers against mosquitoes prevent severe malaria in children. There is need to increase the use of barriers against mosquito bites and to scale up prompt treatment and community-based interventions to reduce the incidence of severe malaria in children.