MK - Cardiac Pharmacology II Flashcards
How do β1 adrenergic receptors (β1 AdrR) influence blood pressure?
They have little effect due to low abundance in peripheral vessels
How do β2 adrenergic receptors (β2 AdrR) influence blood pressure?
Activation relaxes blood vessel smooth muscle, decreasing peripheral resistance and blood pressure.
Blockade constricts vessels, increasing resistance and blood pressure
How do α1 adrenergic receptors (α1 AdrR) influence blood pressure?
Activation constricts blood vessels, raising peripheral resistance and blood pressure
Blockade relaxes vessels, lowering resistance and blood pressure
How do β-blockers (e.g., Propranolol) work to reduce blood pressure?
They block β-adrenergic receptors, reducing sympathetic nervous system effects that can raise blood pressure
How do α1-adrenergic receptor antagonists (e.g., Prazosin) work to reduce blood pressure?
They block α1-adrenergic receptors, preventing vasoconstriction and lowering peripheral resistance
How do dihydropyridine calcium channel blockers (e.g., Nifedipine) work to reduce blood pressure?
They block calcium channels on vascular smooth muscle, preventing calcium influx and relaxation
How do diuretics work to reduce blood pressure?
They increase urine output, reducing blood volume and consequently blood pressure
Treatment of cardiac Dysrhythmias (3)
Phase [0] Blockade of INa –
e.g. Lignocaine fast kinetics Flecainide slow kinetics
Phase [2&4] β- blockers- reduce sympathetic effects NAdr
Phase [2] Voltage-gated Ca channel blockers
e.g. Verapamil, diltiazem
What do Anti-arrhythmic Drugs do?
High-Affinity Block of the Open/Inactivated State of v-gated Na channel
- Reduces repeat excitability
What contributes to Anginal pain? (3)
- Anginal pain when coronary blood flow is inadequate for the metabolic demands of cardiac muscle
- Flows occur during diastole from aorta to ventricles through coronary arteries
- Restricted flow due to atheroma can produce angina on exercise
How do agents decreasing oxygen demand help with angina?
Beta-blockers and calcium channel blockers can reduce heart rate and contractility, lowering oxygen demand.
How do agents increasing oxygen supply help with angina?
Vasodilators can increase blood flow to the heart muscle, improving perfusion
How do nitrates (e.g., organic nitrates) work to treat angina?
They release nitric oxide (NO), which relaxes coronary artery smooth muscle (G-coupled process), increasing blood flow to the heart
What are 3 examples of Nitrous Oxide (NO) donors?
- Nitroglycerin (GTN)
- Isosorbide dinitrate (ISDN)
- Isosorbide-5-mononitrate (ISMN)
What causes a heart attack?
Coronary artery occlusion (blockage) due to atherosclerosis (plaque buildup) reduces blood flow and causes heart muscle death (infarction)
