Pharmacology-Vasodilator Drugs Flashcards
Under what health conditions do we use vasodilator drugs?
Hypertension (reduces BP), CHF (reduces preload and afterload), IHD (increases coronary blood flow).
What factors in our blood cause vascular inflammation?
High glucose, high blood pressure and high cholesterol.
What are your primary goals in prescribing vasodilator drugs? What is your secondary goal?
Lower BP, reduce cardiac workload and increase coronary blood flow. Your secondary goal is acknowledge risk factors.
How is vascular tone regulated?
ANS (neurotransmitters), Neurohormonal systems (catecholamines, RAAS, vasopressin), Vascular endothelium (NO, endothelin) and Local control (H+,CO2, O2, adenosine, lactate, K+)
What is the general mechanism of vasodilating drugs?
Reducer peripheral resistance, increase capacitance and improve coronary flow.
What are the six classes of vasodilating drugs?
ANS, renin-angiotensin-aldosterone, direct vasodilators, calcium channel blockers, phosphodiesterase inhibitors and endothelin receptors.
What vasodilating drugs target the autonomic nervous system?
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What are the direct vasodilating drugs that act on smooth muscle or endothelium?
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What are the vasodilating drugs that target calcium channels?
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What are the vasodilating drugs that inhibit phosphodiesterase?
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What are the vasodilating drugs that target the renin-angiotensin-aldosterone system?
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What are the vasodilating drugs that target endothelia receptors?
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What are the vasodilating drug combinations used in clinical settings?
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What drugs act on alpha-2 receptors to inhibit NE release from vesicles?
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What drugs displace NE and depend on MAO to deplete nerve ending stores of NE in lowering blood pressure?
Reserpine and guanadrel. They inhibit VMAT, which pushes NE into presynaptic vesicles, leaving NE out to be metabolized by MAO.
A 32 year old pregnant woman comes to the ED with a blood pressure o 200/100 and a pulse of 130. She is diagnosed with pre-eclampsia. What drug do you prescribe her to get her blood pressure under control? In what patients is this drug contraindicated?
Oral Hydralazine (Apresoline). It is an ARTERIOLAR vasodilator and will lower her blood pressure. Side effects include reflex tachycardia and increased contractility and thus is contraindicated in patients with heart failure.
An 80 year old patient comes to the ED in hypertensive emergency. He also has severe congestive heart failure. What drug would prescribe to decrease his blood pressure as quickly as possible? In what patients is this drug contraindicated?
IV Sodium nitroprusside. It is a non-specific NO donor that does not need an enzyme to donate NO (as organic nitrate does). This results in ARTERIOLAR and VENOUS vasodilation. It is preferred in patients with CHF. It can result in coronary steal hypotension and is thus contraindicated in patients with ischemic heart disease.
How do calcium channel blockers affect vascular smooth muscle? Cardiac myocytes? Skeletal muscle?
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How do dihydropyridine calcium channel blockers differ from non-dihydropyridine calcium channel blockers differ in the below categories?
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A low renin 70 year old African American presents to the ED with angina pectoris and a BP of 220/120. He also has congestive heart failure. What drug class would be a good pick to get his symptoms under control? What side effects should you warn him of?
Calcium channel blockers, dihydropyridines to be specific. Non-dihydropyridines would be good if he suffered from arrhythmias. Side effects include hypotension.
A 71 year old male comes to see you with severe CHF. There is little hope for him to live more than a year and he is in hypertensive emergency. What would be a good drug to prescribe to this patient? What should you make sure he is not on before you give it to him?
Phosphodiesterase inhibitors. These drugs lead to accumulation of cAMP (increasing contractility) and cGMP (smooth muscle relaxation and vasodilation). You should make sure he is not taking nitrates because that will cause severe hypotension and coronary steal.
