The effect of neomycin on cholesterol metabolism

Oral neomycin lowers serum cholesterol in man, whereas intramuscular doses are ineffective. Probably it exerts its effect in the gastrointestinal tract. It has been suggested that neomycin specifically involves alteration of the intestinal flora. An increased excretion of bile acids and the failure of the conversion of cholic acid to deoxycholic acid has been demonstrated, which supports this hypothesis. It has also been suggested that the decrease in serum cholesterol is related to a malabsorption syndrome. Although large doses of neomycin do cause a malabsorption syndrome there is no agreement as to the occurrence or severity of a malabsorption syndrome related to therapeutic doses of neomycin.