Felodipine in the treatment of hypertensive type II diabetics: effect on glucose homeostasis.

The effect of felodipine on glucose tolerance was evaluated in 18 male type II diabetic patients treated with diet alone, who were hypertensive despite beta-blocker treatment. The study was a double-bind cross-over comparison of placebo and felodipine in addition to beta-blockade. Oral glucose tolerance tests were performed at randomization and at the end of each 4-week double-blind treatment period. The doses of felodipine given were 5 mg b.i.d. for 2 weeks followed by 10 mg b.i.d. for a further 2 weeks. Blood pressure was significantly reduced during felodipine treatment, whereas heart rate remained unaltered. HbA1c and fasting insulin levels did not change during the treatment periods. Fasting and maximal blood glucose levels were not altered between any of the treatment periods. However, there was a small but statistically significant increase (median increase 4%) in the area under the glucose concentration vs. time curve after felodipine as compared to placebo treatment. This increase was not considered to be clinically significant in the short term, but the finding merits further investigation in a rigorous long-term study.