Serum metformin levels in Nigerians with non-insulin-dependent diabetes mellitus.

'Steady state' serum concentrations of metformin have been measured in sixteen Nigerians with non-insulin-dependent diabetes mellitus. There was a thirty-eight-fold variation in the serum levels (50-1886 ng/ml). The mean serum level of metformin was 512 +/- 485.2 ng/ml. This compared favourably with the mean levels (382.3 +/- 76.9 ng/ml) obtained in a similar study in Italians. The observed levels however fell far short of those expected in patients on 1-5 g metformin daily. The role of poor bioavailability vis-à-vis poor patient compliance deserves further detailed pharmacokinetic study.