Long-term safety and efficacy of nevirapine tolerance induction

Background The most frequent side-effects due to nevirapine (Viramune(R)), the first non-nucleoside HIV reverse transcriptase inhibitor introduced for clinical use, are cutaneous hypersensitivity reactions. In non-serious cases, tolerance induction can be proposed. Objective Describe the long-term safety and efficacy of tolerance induction to nevirapine. Methods Six HIV-infected patients started a tolerance 1 to 2 months after an episode of nevirapine hypersensitivity. Increasing doses of nevirapine (2.5, 10, 25, 100, 250 and 750 mug and 2.5, 5, 10, 25, 50 and 100 mg) were given orally at half-hour intervals under strict medical surveillance and patients were followed up regularly. Results All but two of the patients tolerated this induction well. One had a mild and transient reaction on day 1; nevirapine was not stopped. One had a moderate to severe reaction one month later; nevirapine was stopped and he recovered fully. All other patients have been taking nevirapine for more than 3 months without any adverse reaction. Conclusion Therefore, when no alternatives are available in severely ill and hypersensitive HIV-infected patients, tolerance induction is a possible therapeutic option.