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Systemic effects of three β‐blocker eyedrops: Comparison in healthy volunteers of β 1 ‐ and β 2 ‐adrenoreceptor inhibition
Author(s) -
Jeunne Claire Le,
Munera Yves,
Hugues FrançoisClaude
Publication year - 1990
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1990.78
Subject(s) - betaxolol , timolol , blockade , crossover study , placebo , medicine , anesthesia , pharmacology , heart rate , plethysmograph , blood pressure , intraocular pressure , ophthalmology , receptor , alternative medicine , pathology
The β 1 ‐ and β 2 ‐adrenoreceptor blockade by means of the systemic diffusion of three β‐blocker eyedrops—timolol, carteolol, and betaxolol—was evaluated in a randomized, single‐blind, three‐way crossover study in 18 volunteers. The blockade was evaluated by analyzing the variations of the β 1 ‐ and β 2 ‐blockade effects of isoproterenol before and after instillation of one drop in each eye. The β 1 ‐blockade effect was judged on the variation of heart rate, and the β 2 ‐blockade effect was judged on the change in peripheral blood flow measured by veno‐occlusive plethysmography. Comparison of the blockade by these drops showed that carteolol and timolol totally inhibited the β 1 and β 2 effects of a dose of isoproterenol able to increase heart rate by 50% (placebo eyedrops were used as a control). Betaxolol differ significantly because it allowed the same effects with the same dose of isoproterenol. Intensity of the blockade was measured by comparison of the effective doses of isoproterenol. Carteolol and timolol were shown to be four times more inhibitory. Clinical Pharmacology and Therapeutics (1990) 47, 578–583; doi: 10.1038/clpt.1990.78