Premium
Alpha receptor blockade by thymoxamine in the human eye
Author(s) -
Turner Paul,
Sneddon J. M.
Publication year - 1968
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 - 10.1002/cpt19689145
Subject(s) - mydriasis , miosis , phenylephrine , adrenergic receptor , sympathomimetics , pupil , ephedrine , receptor , adrenergic , medicine , pupil diameter , anesthesia , pharmacology , chemistry , biology , neuroscience , blood pressure
Thymoxamine blocks α‐adrenergic receptors in experimental animals. The instillation of 0.1 per cent thymoxamine into the human eye produces miosis which is maximal at 45 to 60 minutes and disappears after 1 to 2 hours. Pretreatment with thymoxamine eye drops prevents the production of mydriasis by phenylephrine 10 per cent or ephedrine 2 per cent. When mydriasis has been established by hydroxyamphetamine 1 per cent, thymoxamine reverses it, and miosis is apparent after 25 minutes. The importance of α‐adrenergic receptors in the mydriatic action of sympathomimetic amines is thus confirmed. This study illustrates the value of pupillary responses in studying the interaction of sympathomimetic amines with adrenergic neuron‐ and receptor‐blocking drugs in man.