Opportunistic infections are a threat to the lives and health of people living with HIV. Cotrimoxazole, an antibiotic also known as trimethoprim-sulfamethoxazole, is used in the treatment and prevention of several opportunistic infections. In patients with HIV/AIDS, cotrimoxazole can cause more drug-related side effects than in the general population. However, there are not many effective alternatives for this drug, which is also by far the cheapest option available. When a patient with HIV experiences a side effect related to cotrimoxazole, often the drug is continued (treating-through) or reintroduced at a later date, either using increasingly larger doses (desensitization), or immediately starting at the full dose (rechallenge). This systematic review is the first to examine the differences in how patients are able to tolerate these strategies.
Three trials examining the use of cotrimoxazole in preventing opportunistic infections were included in the review. When compared to rechallenge, desensitization appeared to result in fewer treatment stoppages and side effects in HIV-infected adult patients who had a previous mild or moderate reaction to cotrimoxazole. However, more data are needed for these results to be conclusive. It is important to note that reintroduction of cotrimoxazole was usually successful using either desensitization or rechallenge, with 44.4% to 79.4% of patients still on cotrimoxazole after six months in the three studies. Furthermore, in the studies reviewed, no strategy resulted in severe hypersensitivity reactions. Severe limitations of this review included the absence of data in paediatric populations and the minimal data from resource-poor populations.