Aqueous humour flow after a single oral dose of isosorbide-5-mononitrate in healthy volunteers.
OBJECTIVE
To investigate whether a nitric oxide donor given as a single oral dose is able to modify aqueous humour flow in healthy volunteers.


METHODS
Ten healthy volunteers participated in a randomized, double-masked and placebo-controlled cross-over study. Aqueous humour flow was assessed by fluorophotometry after intake of isosorbide-5-mononitrate (ISMN), 10 mg. Topical timolol maleate, which is known to reduce aqueous humour flow, was used as a positive control. Intraocular pressure (IOP) was measured by applanation tonometry and blood pressure was registered.


RESULTS
The basal rate of aqueous humour flow did not change significantly after a single oral dose of ISMN. The aqueous humour flow in the timolol-treated eye was reduced as compared to the contralateral control eye (p = 0.002). Mean IOP 6 hours after placebo and ISMN intake did not differ significantly. Timolol lowered IOP by 4 mmHg (p < 0.001). ISMN did not lower systolic blood pressure, but diastolic blood pressure was reduced by 4 mmHg (p = 0.048).


CONCLUSIONS
A single oral dose of 10 mg ISMN had no significant effect on aqueous humour flow in healthy volunteers.
Kotikoski
Hanna
H
Institute of Biomedicine, Pharmacology, Biomedicum Helsinki, University of Helsinki, Finland.
Oksala
Olli
O
Vapaatalo
Heikki
H
Aine
Esko
E
D000284:Administration, Oral; D000328:Adult; D001082:Aqueous Humor / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D015590:Fluorophotometry; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D007548:Isosorbide Dinitrate / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D008297:Male; D020030:Nitric Oxide Donors / Q000008:administration & dosage*; D013999:Timolol / Q000008:administration & dosage; D014065:Tonometry, Ocular
D020030:Nitric Oxide Donors; D013999:Timolol; D007548:Isosorbide Dinitrate; C030397:isosorbide-5-mononitrate