Adherence to antiretroviral and pneumocystis prophylaxis in HIV disease.

BACKGROUND: Medication nonadherence in the treatment of chronic diseases compromises the effectiveness of therapy. Little information is available about the extent of medication adherence or determinants of medication adherence in HIV disease, an issue of increasing importance in this new therapeutic era of combination antiretroviral therapy. METHODS: We studied 244 HIV-infected Medicaid-insured patients attending an HIV hospital-based clinic regarding the extent of and predictors of adherence to antiretroviral therapy and Pneumocystis carinii pneumonia (PCP) prophylaxis. Patients were asked to report medications being taken, patterns of use, and knowledge and attitudes about HIV therapies. Medical record report of type, dose, and frequency of medication was compared with self-report using the kappa statistic. Urine sulfamethoxazole assay was obtained from patients prescribed sulfamethoxazole-trimethoprim. RESULTS: Among patients prescribed antiretroviral therapy, 60% reported > or = 80% adherence in the previous 7 days; 49% reported > or = 80% adherence with PCP prophylaxis in the previous seven days. Seventy-nine percent of patients who reported taking daily sulfamethoxazole-trimethoprim had detectable urinary sulfamethoxazole. In multivariate analysis, > or = 80% adherence to antiretroviral therapy was associated with taking medication < or = twice a day (odds ratio [OR]=1.44; 95% confidence interval [CI], 1.01, 1.96), being likely to take medication when not at home, (OR=1.41; 95% CI, 1.04, 2.00) and patients' belief in their ability to adhere to therapy (OR=1.57; 95% CI, 1.13, 2.17). For PCP prophylaxis, > or = 80% adherence was associated with presence of family (OR=2.39; 95% CI, 1.01, 5.63) and patients' belief in their ability to adhere to therapy (OR=2.87; 95% CI, 1.44-1.78). Sociodemographic characteristics and belief in the efficacy of medications were not associated with adherence. CONCLUSIONS: A relatively low level of adherence to antiretroviral therapy and PCP prophylactic regimens was found. Although our results are principally from patients receiving antiretroviral monotherapy, these findings may have important implications for patients receiving highly active antiretroviral therapy (HAART). Decreasing the complexity of antiretroviral regimens, and working with patients to modify identified barriers to adherence may improve effectiveness of medications and prolong survival.

The hydroxylamine of sulfamethoxazole and adverse reactions in patients with acquired immunodeficiency syndrome.

We measured the urine concentrations of sulfamethoxazole, sulfamethoxazole hydroxylamine, and N-sulfamethoxazole on days 3 and 10 in 15 patients with acquired immunodeficiency syndrome treated with a combination product of trimethoprim (15 mg/kg/day) and sulfamethoxazole (75 mg/kg/day). The percentage of sulfamethoxazole and metabolites excreted on days 3 and 10, respectively, were sulfamethoxazole 17.2% +/- 11.3% versus 15.6% +/- 8.2%; sulfamethoxazole hydroxylamine 2.6% +/- 2.0% versus 5.0% +/- 5.2% (p < 0.05); N-acetylsulfamethoxazole 80.0% +/- 12.9% versus 79.8% +/- 11.8%. The percentage of sulfamethoxazole hydroxylamine excreted was similar between the eight patients who discontinued therapy because of toxicity and the seven patients who did not (2.9% +/- 2.3% versus 2.3% +/- 2.0%, p = 0.7). In two patients who had major liver toxicity the percentage of sulfamethoxazole hydroxylamine excreted was significantly lower than that of the 13 patients who did not (0.8% +/- 0.1% versus 2.9% +/- 2.0%, p < 0.05). This is the first report of the formation and excretion of sulfamethoxazole hydroxylamine in patients with acquired immunodeficiency syndrome. With 15 patients we were unable to show a significant correlation between the percentage of sulfamethoxazole hydroxylamine excreted and adverse reactions. However, patients with liver toxicity excreted less sulfamethoxazole hydroxylamine.