Effect of neomycin sulphate alone and in combination with D-thyroxine on serum lipoproteins in hypercholesterolaemic subjects.

Treatment with neomycin sulphate 1.5 g/d for 8 weeks significantly lowered total serum cholesterol by an average of 19% in 15 out of 19 patients with primary hypercholesterolaemia and LDL-cholesterol by 21%, without significantly changing the corresponding triglyceride and HDL-cholesterol concentrations. Combined treatment with neomycin sulphate 1.5 g/d and d-thyroxine 6 mg/d for 8 weeks lowered total serum cholesterol in the same patients by an average of 30%, LDL-cholesterol by 27% and serum triglycerides by 18%, without significantly changing the HDL-cholesterol concentration. Continued treatment for 10 patients with neomycin sulphate 1.5 g/d for up to 13 months did not further change the reduced serum cholesterol level. 10 of 19 patients complained of side effects after 4-8 weeks of treatment with neomycin: 8 of recurrent diarrhoea, abdominal pain or poor appetite, and 4 of acute attacks of vertigo with nystagmus. All side effects were reversed a few days after stopping the neomycin treatment. No additional serious side effects due to d-thyroxine were observed. These serious side effects of neomycin sulphate limit its use to selected high risk patients with hypercholesterolaemia, who have failed to respond successfully to other LDL-cholesterol-lowering drugs. They stress the necessity for frequent monitoring for the side effects described.