Paper Information

Title: 

EFFECTIVENESS OF COMMON ADMINISTERED DOSES OF GLYCERYL TRINITRATE AND ISOSORBIDE DINITRATE IN HEALTHY VOLUNTEERS, USING LASER DOPPLER FLOWMETRY

Type: POSTER
Author(s): MIRKHANI H.*,FADAKAR P.,HOJATI HOSSEIN
 
 *DEPARTMENT OF PHARMACOLOGY, SHIRAZ UNIVERSITY OF MEDICAL SCIENCES, SHIRAZ, IRAN
 
Name of Seminar: IRANIAN CONGRESS OF PHYSIOLOGY AND PHARMACOLOGY
Type of Seminar:  CONGRESS
Sponsor:  PHYSIOLOGY AND PHARMACOLOGY SOCIETY, MASHHAD UNIVERSITY OF MEDICAL SCIENCE
Date:  2009Volume 19
 
 
Abstract: 

Organic nitrates are one of the most used agents in ischemic heart disease. To our knowledge, no study has been published to determine the clinical effectiveness of available oral preparations in Iran. In a double-blind cross-over clinical study, the effects of single dose oral glyceryl trinitrate (GTN, 3.2 and 6.4 mg) and isosorbide dinitrate (ISDN, 10 and 20 mg) on facial skin blood flow of normal volunteers were assessed by laser Doppler flowmetry. Moreover, to study the nitrate tolerance phenomenon, in another group of volunteers the effect of 3 days continuous GTN patch usage on the effect of sublingual GTN on skin blood flow and platelet Cgmp level were determined. ISDN had a faster and greater effect on skin blood flowcompared to GTN. For both ISDN and GTN, lower doses showed greater responses compared to larger doses. In 3 of 5 cases, the tolerance phenomenon was observed (i. e. failure of sublingual GTN to increase blood flow after 3 days of continuous GTN patch usage). Continuous 3 days GTN patch administration, significantly reduced platelet cGMP level in all cases and thereafter, sublingual GTN failed to increase this level. In conclusion, available oral organic nitrates in Iran are bioavailable. It seems that the lower doses have a greater vasodilatory effect on skin vessels. The occurrence of nitrate tolerance is not a universal phenomenon. Finally, laser Doppler flowmetry, is a non-invasive and an easy to use method to study the effect of drugs on superficial blood flow.

 
Keyword(s): GLYCERYL TRINITRATE, ISOSORBIDE DINITRATE, LASER DOPPLER FLOWMETRY, SKIN BLOOD FLOW, CGMP
 
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