Assessment of systemic effects of different ophthalmic beta-blockers in healthy volunteers.
Systemic beta-blockade after single doses of ophthalmic beta-blockers (one drop in each eye) was investigated in healthy volunteers in two randomized, double-blind, crossover, placebo-controlled studies. beta-Blockade was evaluated by displacement of the bronchodilator (specific airway conductance), positive chronotropic (heart rate), and tremorogenic (finger tremor amplitude) dose-response curve for inhaled isoproterenol. In study 1, 0.5% betaxolol, 0.6% metipranolol, and 0.5% timolol were tested in 16 subjects. Compared with placebo, all beta-blockers resulted in a significant systemic beta-blockade (p greater than 0.05); the increasing order of potency was betaxolol, metipranolol, and timolol. In study 2, 2% butylamino-phenoxy-propanol-acetate (BPPA; a noncardioselective but topically oculoselective drug) and 1% timolol were investigated in 12 subjects. Placebo and BPPA showed no differences (p greater than 0.05), whereas timolol resulted in a significant beta-blockade (p less than 0.05). Topical oculoselectivity is an important aspect of drug safety of beta-blocking eyedrops. Measure of tremor is appropriate to evaluate beta 2-blockade.
Division of Internal Medicine I, University of Vienna Medical School, Austria.
K
K
Bauer
F
F
Brunner-Ferber
L M
LM
Distlerath
E A
EA
Lippa
B
B
Binkowitz
P
P
Till
G
G
Kaik
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000328:Adult; D001980:Bronchi / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005385:Fingers; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009883:Ophthalmic Solutions; D014202:Tremor / Q000139:chemically induced
D000319:Adrenergic beta-Antagonists; D009883:Ophthalmic Solutions; D007545:Isoproterenol