Cardiovascular Pharmacology Questions-Henkin Flashcards
What is the most important consideration in choosing a blood pressure medication?
Heart rate
When are diuretics given to control BP?
To decrease preload or if volume overload.
What is a satisfactory time in which the target heart rate should be reached in a stress test?
7-13mins (better if more)
What is the main action of diuretics?
Increase urinary sodium and decrease blood volume
What is the main action of beta adrenergic blockers?
Decreased HR and renin, increased peripheral resistance
What is the main action of calcium antagonists?
Vasodilation, decreased AV conduction, decreased heart rate. Block L-type voltage gated calcium channels. Reduces the calcium entering cells, reducing contraction. Reduces afterload.
What is the main action of ACE inhibitors?
Vasodilators
What is the main action of alpha blockers?
Vasodilators
What is the main action of ARBs?
Vasodilators
What groups respond best to diuretics?
African-Americans and older people, with volume overload and sodium retention.
When are beta blockers used for HTN?
In patients with tachycardia, heart failure, coronary artery disease, and ischemia. Otherwise not first line because of side effects.
What drugs are considered first line for HTN (barring side effects)?
Calcium antagonists and ACE inhibitors
When are ARBs used in HTN?
Usually only as a replacement for ACE inhibitors for those that can’t tolerate them or occasionally in combinatino.
When are central acting drugs used for HTN?
Generally not used except for those resisting all other drugs and very difficult cases. Lots of side effects.
Effects of the sympathetic system on the heart
Mechanism of action of beta blockers
↓ myocardial contractility (negative inotropism, increased in long term use), ↓ heart rate (negative chronotropism), membrane stabilizing activity (quinidine-like), ↓ renin levels (↓ angiotensin II ↓ aldosterone), reduces arrhythmias of all types (atrial and ventricular).
What is the caveat to selective beta agonists?
At high doses, no longer selective.
What kind of selectivity is ideal for CV problems?
Want beta 1 blocked but not beta 2 because of bronchoconstriction and other effects.
What are the 3 classifications of considerations of Beta Blockers?
- Selectivity, 2. Water/fat solubility and halflife, 3. intrinsic sympathomimetic activity (ISA)
How are Beta blockers with Intrinsic sympathetic activity (ISA) different?
Some beta blockers also have partial antagonist and partial agonist activity. Under basal resting conditions stimulate center (weak stimulation of beta-adrenergic receptors) but once pt secretes more adrenaline, acts as antagonist-blocks catecholamine effects. Gives advantage of not causing bradycardia at rest, preventing tachycardia during exercise. Unlike other beta blockers, not show n to decrease mortality during MI (may slightly increase it) or after HF.
How does negative chronotropism affect the heart rate?
- Reduces sinus rhythm, 2. Can cause AV blocks
What are the adverse effects of beta blockers?
Negative choronotropism (bradycardia, AV blocks), Negative ionotropism, Bronchospasm, Insulin resistance, Peripheral vasoconstriction, Unopposed alpha stimulation.
How do beta blockers adversely affect diabetic patients?
Can mask hypoglycemia because patients know they are hypoglycemia due to sympathetic response.
Why are peripheral artery disease patients excluded from beta blocker therapy?
Because of vasoconstriction from unopposed alpha receptors.
What are the 3 classes of calcium channel blockers?
Verapamil, Diltiazem, Dihydropyridines
What is the major difference between beta blockers and calcium channel blockers?
Beta blockers reduce sinus activity at rest and during exercise. Ca channel blockers reduce at rest but don’t counteract effect of adrenergic stimulation. Don’t reduce tachycardia during exercise so not as good at preventing exercise induced angina.
How do dihydropyridines differ from other calcium channel antagonists?
Potent arterial dilation reduces blood pressure and causes reflex tachycardia but counteracted by effect on SAN and AVN so slight tachycardia remains.
Adverse effects of dihydropyridines
Vasodilation (flushing, headache, palpitations), ankle edema in about 5%
What was the effect of now discontinued fast acting dihydropyridines?
Caused reflex sympathetic response which caused increased mortality.
Adverse effects of verapamil
Bradycardia, AV block, constipation (especially with beta blockers)
Which calcium channel blocker has the highest effect of decreased contractility and AV conduction?
Verapamil
Which has a shorter half life, fat or water soluble drugs?
Fat soluble because it must first go through the liver. Dosing is variable.
Which kinds of drugs can pass the BBB and what are the adverse effects?
Penetrate the brain more easily and cause depression, sleep defects, etc.
What drug should be given to a patient with angina, tachycardia, HTN and 1st degree AV block?
Nitroglycerine. AV blocks are contraindication for beta blockers.
What is the difference in effects between IV and oral nitrates?
Orally is mostly venous and IV or subcutaneous is both artery and veins because of first pass.
What are the vascular effects of low concentrations of nitrates (orally)?
venous dilatation Increase venous capacitance ↓ ventricular preload (Starling low) ↓ pulmonary vascular pressure ↓ heart size increase in total coronary blood flow Redistribution of coronary flow from normal to ischemic region.
What are the vascular effects of high concentrations of nitrates (IV)?
arterial dilatation ↓ afterload, ↓ blood pressure.
Michanism of tolerance of nitrates
In order for NO to be activated, need SH groups prduced in the liver. Liver can’t keep up with constant production. Need to give the body a few hours for thiol (SH) replenishing. Should never give TID, usually if need to give BID tell patients to take in morning and noon and give night a rest.
When should a patient take nitrates if they have nocturnal angina?
Take in afternoon and night, morning rest.