PILOT-STUDIES OF AZITHROMYCIN, LETRAZURIL AND PAROMOMYCIN IN THE TREATMENT OF CRYPTOSPORIDIOSIS

Pilot studies of the safety and efficacy of 3 drugs thought to have an ticryptosporidial activity were carried out to determine whether any o f them are suitable for large-scale clinical trials. Open studies of t he use of azithromycin, letrazuril and paromomycin in patients with ac quired immunodeficiency syndrome (AIDS) and confirmed cryptosporidial diarrhoea for at least a month. Azithromycin 500 mg daily was ineffect ive. Letrazuril 150-200 mg daily was associated with an improvement in symptoms in 40% of patients treated and cessation of excretion of cry ptosporidial oocysts in the stool in 70%; however biopsies remained po sitive. Paromomycin therapy was associated with a complete resolution of diarrhoea in 60% of patients treated and some improvement in sympto ms ina further 5% but it did not eliminate the infection. None of the drugs had any major toxicities. Dose escalation studies of azithromyci n should be performed. Letrazuril should be further investigated for e fficacy in double-blind placebo-controlled trials. Paromomycin appears to result in prolonged symptomatic remission of cryptosporidial diarr hoea, but has no effect on cryptosporidial cholangitis.