Pharmacology - Drugs Affecting Blood Pressure Flashcards
What is the role of endothelium in vascular smooth muscle relaxation?
The endothelium is stimulated by vasodilating humoral agents which cause it to produce NO.
The NO goes into the smooth muscle cell and stimulates the cell to relax. Slide 4
In clinical context which doses do organic nitrates target in the vasculature?
Small doses - venorelaxation
High doses - arteriolar dialtion. Slide 5
What is the effect of organic nitrates upon the coronary circulation if there is an atheromatous plaque to one of the coronary arteries?
A collateral vein forms but is rather small.
NO dilates the collateral artery whcih increases the blood flow to the ischaemic area. Slide 6
What are some examples of organic nitrates which are used in stable angina?
Gluceryltrinitrate and isosorbide mononitrate. Slide 7
What happens if the endothelial cell is stimulated by adrenaline, ADH or angiotensin II?
Creates a positive effect on the production of endothelin which is a protein that stimulates the smooth muscle cell to contract. Slide 8
What are the clinical uses of b blockers in angina?
Decrease the O2 consumption by the heart and counter the increased symapthetic activity. It increases the amount of time for coronary blood flow(time spent in disatole) whcih means there is increased perfusion. Slide 15
In the CVS what diseases can b blockers treat?
Angina
Hypertention (not first line)
Heart failure. Slide 16
What do calcium antagonists do and where do they interact?
Prevent the L type Ca channels from opening which reduce conduction through the AV node and can have a negative inotropic effect.
They act mainly in the heart and smooth muscle. Slide 17
What are the 3 main types of Ca antagonists and what do each target?
Verapamil - Selective for cardiac L channels
Amlodipine - Selective for smooth muscle L channels
Diltiazem - Both L channels. Slide 18
What are the uses of Ca antagonists and how?
Hypertension - reduce Ca entry in smooth muscle and causes dilation
Angina - Prophylactic treatment in increasing peripheral arteriolar and coronary dilation
Dysrhythmias - Ventricular rate is reduced by suppression of AV node in someone with AF. Slide 20
What do potassium channel openers do and what are examples of these drugs?
They open K channels which causes hyperpolarisation and switches of Ca channels. This causes relaxation of the smooth muscle.
Minoxidil and nicorandil are examples. Slide 21
What do a1-adrenoceptor antagonists do and what are examples?
Vasodilation and that reduces MAP.
Prazosin and doxazosin are examples. Slide 22
