Viewpoints Opportunistic infections in AIDS: treatment and prophylaxis

It is imperative 'that the life-threatening opportunistic infections that occur and recur in AIDS sufferers are treated and/or kept in check in order to prolong life and improve its quality.

Problems may arise when unsuitable drugs are administered or when side effects occur. As a variety of organisms may be the aetiological agents of a single syndrome, unsuitable treatment may be administered, e.g. oesophagitis, which may occur without concurrent oral lesions, could result from an infection with Candida species, Herpes simplex or cytomegalovirus. Regarding side effects, it is unfortunate that drug therapy may aggravate the deteriorating haematopoietic system as the AIDS virus takes its effect, leaving the body even more vulnerable to infection. Neutropenia may be caused by cotrimoxazole, pentamidine, flucytosine, zidovudine or the investigational agent, ganciclovir. This condition may precipitate a severe infection with Pseudomonas aeruginosa.

Either cotrimoxazole or pentamidine is effective in treating Pneumocystis carinii infections. While the former drug may give rise to hypersensitivity reactions, the latter can adversely affect hepatic and renal function and also cause hypoglycaemia. It is suggested that 1-2 drug-free days follow the fifth dose of pentamidine. Trimethoprim in combination with dapsone (800mg + 100 mg/day) is an investigational alternative to cotrimoxazole which may be less allergenic. Chemoprophylaxis is important in patients with AIDS-lymphoma and Kaposi's sarcoma as they are highly prone to developing P. carinii pneumonia. Prophylaxis is also necessary to prevent recurrence. It has been found that most patients who experienced dermal reactions to cotrimoxazole were able to tolerate the 1 : 20 combination of pyrimethamine with sulfadoxine. Aerosol delivery of pentamidine is under investigation and may be useful for prophylactic treatment.

As the aetiological organisms responsible for diarrhoea in AIDS differ from those in the 'gay-bowel syndrome' it is recommended that high risk patients presenting with diarrhoea be carefully investigated. Salmonella and shigella are easily treated with ampiCillin and Isospora belli with cotrimoxazole. These treatable organisms should be considered before cryptosporidia. Young LS. Lancet 2: 1503·1506,26 Dec 1987

2 INPHARMAe 16 January 1988 0156-2703/88/0116-0002/0$01.00/0 © ADIS Press