| Eighteen patients with non-insulin-dependent (type 2) diabetes
mellitus of normal body weight [body mass index (BMI) <25 kg/m2]
without signs of autoimmunity [negative for islet cell antibodies
(ICA)], with secondary failure of sulphonylureas, defined as
persistent hyperglycaemia in spite of maximal doses of
sulphonylureas, were evaluated for C-peptide release under basal
conditions and 6 min after i.v. glucagon, for glycosylated
haemoglobin (HbA1C), and for fasting and mean daily blood glucose
levels. They entered a 6-month, single-blind study in which they were
randomly assigned to one of three treatments: (1) insulin plus
nicotinamide (group 1, 0.5 g, three tablets/day); (2) insulin plus
placebo (group 2, 3 tablets/day); (3) current sulphonylureas plus
nicotinamide (group 3, 0.5 g, three tablets/day). They were re-
evaluated for C-peptide, HbA1C, and fasting and mean daily blood
glucose levels after 6 months. Compared with group 2, C-peptide
release increased in both groups 1 and 3, while HbA1C, fasting and
mean daily blood glucose levels improved in the three groups to the
same extent. With multiple regression analysis, nicotinamide
administration was the only significant factor for the improvement of
C-peptide release. These data indicate that nicotinamide improves C-
peptide release in type 2 diabetic patients with secondary failure of
sulphonylureas, leading to a metabolic control similar to patients
treated with insulin.
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