Vasodilators are drugs causing blood vessels dilatation.
Classification of vasodilators[edit | edit source]
- coronary – nitrates, nitrites, molsidomine;
- others – Ca2+ Channel blockers, hydralazines, nitroprusside , minoxidil, diazoxide, purines, nicotine derivatives, others.
2.Neurotropic – α1-lytic
- non-selective – phentolamine, phenoxybenzamine;
- selective – prazosin, doxazosin, metazosin.
- It is advisable to divide the individual drugs according to the site of action
- mainly for arterioles – hydralazines, Ca2+ antagonists , phentolamine, purines, nicotinic acid derivatives, others;
- mainly for veins – nitrates, molsidomine (at higher doses also arterioles);
- for arterioles and veins – selective α1-lytic, ACEI, nitroprusside.
Direct vasodilation[edit | edit source]
They reduce blood pressure by dilating the effect on vascular smooth muscle - thereby reducing peripheral vascular resistance while maintaining compensatory mechanisms mediated by baroreceptors, sympathetic nerves and the renin-angiotensin-aldosterone system ( RAAS ). This fact has its advantages and disadvantages.
- The advantage is that the vasodilators are not hypotensive , they dilate the renal arterioles, so they do not restrict renal flow . They do not affect sexual function . They can be given during pregnancy.
- The disadvantages are fluid retention by RAAS activation and the subsequent possible expansion of extracellular volume, undesired reflex tachycardia, and a decrease in the antihypertensive effect due to compensatory effects. The mentioned disadvantages can be balanced by combination with β-lytics (in case of contraindication β-lytics they can be combined with methyldopa , clonidine ). The risk of fluid retention can be avoided by concomitant administration of diuretics .
- Sodium nitroprusside
Links[edit | edit source]
Related articles[edit | edit source]
- Treatment of ischemic heart disease
- Renin-Angiotensin-Aldosterone system
- Angiotensin II receptor blockers
- Hypertensive crisis
Source[edit | edit source]
- MARTÍNKOVÁ, Jiřina – MIČUDA, Stanislav – CERMANOVÁ, Jolana. Vybrané kapitoly z klinické farmakologie pro bakalářské studium : Kardiovaskulární systém [online]. ©2000. [cit. 2010-07-01]. <https://www.lfhk.cuni.cz/farmakol/predn/bak/kapitoly/prednasky/kardio-bak.ppt/>.