Intravenous administration of diphenhydramine reduces histamine-induced vasodilator effects in the retina and choroid

Investigative Ophthalmology & Visual Science
Günther WeigertGerhard Garhöfer

Abstract

Intravenous administration of histamine causes an increase in choroidal blood flow (ChBF) and retinal vessel diameters in healthy subjects. The receptor mediating this response has not yet been identified. The present study was undertaken to clarify whether H1 receptor blockade with diphenhydramine affects the hemodynamic response of histamine in the choroid and the retina. A randomized, double-masked, placebo-controlled, two-way crossover study was performed in 18 healthy, male, nonsmoking subjects. Histamine (0.32 microg/kg per minute over 30 minutes) was infused intravenously in the absence (NaCl as placebo) or presence of the H1 blocker diphenhydramine (1.0 mg/min over 50 minutes). Ocular hemodynamic parameters, blood pressure, and intraocular pressure were measured before drug administration, after infusion of diphenhydramine or placebo, and after co-infusion of histamine. Subfoveal ChBF and fundus pulsation amplitude (FPA) were measured with laser Doppler flowmetry and laser interferometry, respectively. Retinal arterial and venous diameters were measured with a retinal vessel analyzer. Retinal blood velocity was assessed with bidirectional laser Doppler velocimetry. Administration of histamine caused a decrease in mean a...Continue Reading

Citations

Mar 16, 2013·British Journal of Clinical Pharmacology·Euan A SandilandsDavid J Webb
Jul 30, 2010·Neurogastroenterology and Motility : the Official Journal of the European Gastrointestinal Motility Society·T HattoriS Fukudo
Dec 30, 2014·PloS One·Ursula GreferathErica L Fletcher
May 22, 2008·Canadian Journal of Ophthalmology. Journal Canadien D'ophtalmologie·Mark R LeskMicheline C Deschenes
May 15, 2020·Journal of Applied Physiology·Matthew R ElyJohn R Halliwill

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