A comparison of phenformin and metformin in the treatment of maturity onset diabetes.

A comparison of the effects of two dose levels of phenformin (50 mg once and twice daily) and metformin (850 mg twice daily and 1,700 mg twice daily) has been undertaken in 24 maturity onset diabetics whose diabetes had remained inadequately controlled with dietary measures alone. Both biguanides effectively reduced the fasting blood sugar and body weight of the patients, metformin apparently having a greater effect on blood sugar than phenformin. Serum triglycerides were lower on the larger dose of metformin than on either dose of phenformin. Both drugs in the larger doses reduced the serum cholesterol. Side effects were more common with metformin, particularly in the higher dosage and overall control of the diabetes was achieved in the same proportion of patients (33%).