Influence of hypoglycemic therapy on blood lipids and body weight in diabetes mellitus

Comparative effects of phenformin, metformin and glibenclamide on metabolic rhythms in maturity-onset diabetics

Twelve hour metabolic rhythms have been performed on six maturity-onset diabetic subjects during successive periods of therapy with phenformin, metformin, and glibenclamide. Moderate control of blood glucose concentration was achieved with phenformin and metformin, the lowest concentrations being found with glibenclamide. Mean blood lactate concentration was grossly elevated during phenformin therapy, moderately elevated with metformin and normal during glibenclamide treatment. Similar patterns were found for the lactate/pyruvate ratio, alanine, glycerol and ketone bodies. Serum triglyceride concentrations were significantly higher during phenformin treatment than with the other two regimes. Serum insulin concentration was higher on glibenclamide than with either biguanide. Most of these effects of the biguanides could be accounted for by an inhibitory effect on hepatic gluconeogenesis. It is concluded that the use of biguanides as hypoglycaemic agents in diabetes is associated with the production of multiple metabolic abnormalities.

The effect of phenformin-HCl on patients with diabetes mellitus, studied under strict balance conditions

Under strict balance conditions we studied the effect of phenformin in 5 patients with diabetes mellitus. In all cases phenformin lowered the blood glucose values, and all patients showed a reduction of glycosuria. Contrary to other reports body weight increased during phenformin treatment. This was accompanied by positive nitrogen, phosphorus and calcium balances. The weight gain can be explained by the positive caloric balance, mainly caused by the diminished glycosuria. No change in B.M.R. or R.Q. was seen. During phenformin treatment there was a drop in cholesterol and total lipid levels in 4 patients. No conclusions could be drawn about the effect of phenformin on triglycerides, phospholipids and lipoprotein spectra. Phenformin treatment did not affect the disappearance of glucose, nor the insulin levels after intravenous glucose loading. During oral glucose loading phenformin caused a significant fall in blood glucose levels, accompanied by an increased insulin response in one patient. In the other 4 patients phenformin had no effect on either parameter.

Antifibrin action of phenformin

Effects of phenformin on blood sugar, serum triglyceride, thrombin time, euglobulin clot lysis time and cardiovascular complications were studied in maturity onset diabetes and in atherosclerotic patients with or without diabetes, for a period of 14-18 months. Phenformin has shown the characteristic properties of an antifibrinopathic agent in that it prolongs thrombin time and enhances fibrinolysis. The hypoglycaemic effect of phenformin was found to be directly related to its antifibrinopathic action. Plasma lipids fell in all cases. Absence of fresh cardiovascular complications and improvement in anginal symptoms were observed. The metabolic, haematological and clinical benefits of phenformin and its limitations in maturity onset diabetes and atherosclerosis may be explained by the effects of the drug upon the thrombin-fibrinogen reaction. These results lend support to the hypothesis of a primary fibrinopathic pathogenesis in maturity onset diabetes mellitus and atherosclerosis.

Pheniformin in insulin-dependent diabetics

Forty-one diabetic patients on insulin were given 100mg. of phenformin daily for six weeks, either before or after a period of six weeks of inert capsules, in a double-blind cross-over trial. Eleven patients while on phenformin noticed hypoglycaemic effects and reduced their insulin on average by almost 20% without resultant rise in blood sugar levels. Twenty-eight patients felt no untoward effects and maintained their usual insulin dose. Phenformin led to improved control of the diabetes, with a significant decrease in blood sugar levels and a significant reduction in the variability of the weekly blood sugar readings. There was no increased ketosis, no change in cholesterol, and no significant loss of weight.