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Flashcards in Drug Treatment of Cardiovascular Disease Deck (19)
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How can the vascular endothelium be dilated to reduce blood pressure?

Substances such as endothelin and nitric oxide


How can the vascular endothelium be constricted to reduce blood pressure?

Substances such as catecholamines


What is angina?

The pain or discomfort arising from ischaemia of myocardial muscle generally due to atherosclerotic obstruction of coronary blood vessels


How is angina treated?

Aim is to improve/restore coronary blood flow OR reduce the workload of the myocardium and hence the oxygen demand it requires --> as angina is often due to ischaemia of myocardium


How may nitrates be used in the treatment of angina?

Have a dilatory effect so work to reduce preload, reducing the work of the heart


How may beta-1 adrenoreceptor antagonists (beta blockers) be used to treat angina?

Activation of beta-1 receptor usually activates the sympathetic NS and adrenal glands (increasing heart rate, myocardial contractility and conduction through AVN). Therefore, beta blockers impede this activation to reduce the work of the myocardium and hence it’s required oxygen demand


How may calcium channel blockers be used to treat angina?

Reduces Ca2+ influx through voltage gated channels on myocyte membrane --> reduced intracellular Ca2+ which reduces the contractility in myocytes and vascular smooth muscle which reduces oxygen demand due to improved supply in the coronary arteries and reduces work of the heart


Name three treatments for hypertension

ACE inhibitors, calcium channel blockers and diuretics


Describe how ACE inhibitors can treat hypertension

Interrupts RAAS system (prevents angiotensin I being converted to angiotensin II) which prevents sodium and water retention at the kidney as well as the stimulation of vascular smooth muscle constriction, vasodilation --> reduced BP


Describe how calcium channel blockers can reduce hypertension

Block calcium entry to the vascular smooth muscle and myocardial cells (interrupting excitation-contraction coupling) in order to prevent constriction --> cause vasodilation


Describe how diuretics can reduce hypertension

Thiazide-type are used to prevent the reabsorption of sodium (and water) in the distal tubule and early collecting duct in order to decrease intravascular volume, and decrease BP


Describe heart failure

Severe failure of the heart to function properly; insufficient CO to delivery necessary blood flow to the tissues --> pulmonary congestion, difficulty breathing and peripheral oedema


What are the main causes of heart failure?

Ischaemic heart disease as well as valve defects and dysrhythmias


What is preload proportional to?

Venous return


What is afterload proportional to?

Systemic vascular resistance


How can afterload be reduced?

ACE inhibitors (as angiotensin II is responsible for stimulating vasoconstriction)


How can preload be reduced?

Diuretics - inhibit water reuptake and therefore reduce the total blood volume


Describe the mechanism of action of digoxin in the treatment of heart failure

Selectively binds to and inhibits myocyte Na+/K+ ATPase so that intracellular Na+ rises in the cells and Na+/Ca2+ exchange is altered to increase intracellular Ca2+ to improve contractility with depolarisation and may have direct action on conduction at AVN – decreases automaticity, slows the conduction velocity and slows HR


What are the aims of treatment for heart failure?

Reduce preload and afterload in the heart