Bile acid, neutral sterol and faecal fat excretion in subjects treated with fenfluramine and its relationship to fenfluramine-induced diarrhoea.

Bile acid, neutral sterol and faecal fat excretion was studied over a period of 9 weeks in a group of 16 healthy subjects before, during and after administration of fenfluramine. Statistical analysis revealed a significant increase in bile acid excretion during the drug phase (P less than 0.02); and during recovery period of 3 weeks (P less than 0.05). Faecal neutral sterol, as the total of coprostanol and cholesterol elimination was also enhanced after fenfluramine. Coprostanol was replaced by cholesterol in 12 subjects. Faecal fat was studied in 6 subjects, the excretion increased during the drug phase (P less than 0.05), and remained elevated during the post-drug period (P less than 0.01). The composition of the bile acids remained unaltered in all the subjects except 3 who had a fenfluramine-induced watery diarrhoea; and these excreted chenodeoxy and cholic together with smaller amounts of secondary bile acids. A higher excretion of bile acids was found in the 8 overweight subjects (P less than 0.01) before ministration of fenfluramine. These results are discussed in an attempt to correlate the effect of fenfluramine with changes in bile acid and neutral sterol excretion, and its relationship to fenfluramine-induced diarrhoea.