Effects of nebivolol and atenolol on insulin sensitivity and haemodynamics in hypertensive patients.
OBJECTIVE
To compare the effects of nebivolol and atenolol in 25 ambulatory hypertensive patients with impaired glucose tolerance.


METHODS
Clinic and ambulatory blood pressure, insulin sensitivity (euglycemic-hyperinsulinemic clamp), glucose tolerance (intravenous glucose tolerance test), systemic and regional haemodynamics were measured after 4 weeks of placebo and after each 16-week treatment period in a double-blind, crossover fashion.


RESULTS
Nebivolol and atenolol similarly reduced (P< 0.001) clinic and ambulatory blood pressure by approximately 15/10 mmHg, systolic and diastolic. Clinic and ambulatory heart rate was reduced to a greater extent (P < 0.01) by atenolol than nebivolol. Atenolol was associated with an approximately 20% reduction in insulin sensitivity (insulin-induced glucose disposal rate/mean insulin concentration ratio, P < 0.01) and an approximately 10% reduction in glucose disappearance rate (K-value, P < 0.05), whereas these variables were not significantly modified with nebivolol. Cardiac output was reduced similarly (P < 0.05) by both drugs at rest but forearm blood flow, forearm vascular resistance or total peripheral resistance were unaffected. A significant inverse correlation coefficient between cardiac output and insulin sensitivity was found at baseline, suggesting that a compensatory increase in systemic blood flow occurs in hypertensive patients with progressively more marked insulin resistance. This relationship was unaffected by nebivolol but was lost with atenolol.


CONCLUSIONS
These results indicate that insulin sensitivity was not modified significantly by nebivolol, whereas it was reduced by atenolol, although blood pressure was decreased to the same extent by both drugs. Neither drug induced systemic or forearm vasodilatation but the inverse relationship between cardiac output and insulin sensitivity was preserved with nebivolol but not with atenolol.
Poirier
L
L
Hypertension Unit, Centre Hospitalier Universitaire de Québec (Pavillon CHUL), Université Laval, Canada. luc.poirier@crchul.ulaval.ca
Cléroux
J
J
Nadeau
A
A
Lacourcière
Y
Y
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001262:Atenolol / Q000627:therapeutic use*; D001578:Benzopyrans / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004983:Ethanolamines / Q000627:therapeutic use*; D005260:Female; D005951:Glucose Tolerance Test; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology*; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D000068577:Nebivolol
D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D001578:Benzopyrans; D004983:Ethanolamines; D000068577:Nebivolol; D001262:Atenolol