Antihypertensive therapy with guanfacine induces elevated plasma growth hormone levels in diabetic patients.

Guanfacine, a central alpha-adrenoreceptor agonist, may increase growth hormone (GH) secretion. We have investigated the effect of guanfacine upon plasma GH levels in 16 hypertensive non-insulin-dependent diabetic (NIDD) patients. Guanfacine (1 to 2 mg/day/os) was administered for six months, and GH measured in basal plasma samples before and after treatment with this drug. Our results show an increase in GH plasma levels after guanfacine administration (2.88 +/- 2.05 ng/ml (X +/-SD) before, and 4.37 +/- 1.80 ng/ml (X +/- SD) after treatment). Since it is believed that GH levels plays a role in the course of diabetic retinopathy, caution should be taken with guanfacine antihypertensive treatment in patients affected with diabetes mellitus.