Vascular drugs Flashcards
Alpha 1 receptor main therapeutic actions & adverse reactions
Main actions:
Vasoconstriction of veins & arteries + pupil dilation, used for hemostasis, prolonging local anesthesia, and to elevate BP in hypotensive pts
Adverse reactions:
Necrosis secondary to local vasoconstriction
Bradycardia
Hypertension
Alpha 2 receptor therapeutic actions & adverse reactions
Alpha 2 receptors in CNS cause reduction of sympathetic activation of heart and blood vessels, and relief of severe pain.
No clinical significance in periphery.
No significant AEs.
Beta 1 receptors therapeutic actions and adverse reactions
Therapeutic actions:
Increased force of myocardial contraction, increased heart rate, increased speed of conduction through AV node. Used to treat severe HF and/or hypovolemic shock, AV heart block, cardiac arrest secondary to asystole.
Adverse reactions:
Angina secondary to increased myocardial O2 demand, tachycardia, dysrhythmias
Beta 2 receptor therapeutic actions and adverse reactions
Therapeutic actions:
Bronchodilation in lungs for treatment of asthma, vasodilation of arterioles in heart, lung, skeletal muscle, breakdown of glycogen (incr. BG), relaxation of uterus
Adverse reactions:
Hyperglycemia, tremor secondary to skeletal muscle contraction
Epinephrine (Adrenalin)
Class: Adrenergic agonists/catecholamines
MoA:
α 1, α 2, β 1 effects:
* ↑BP (vasoconstriction)
* ↑ HR
* ↑speed of conduction through AV node
* ↑contractility of heart → ↑ CO.
* Restore cardiac function in cardiac arrest.
β 2 effects:
* Bronchodilation
* increase blood flow to heart
* lung and skeletal muscle
* increased blood sugar for energy.
Uses:
Cardiac arrest, severe hypotension /shock (IV)
Anaphylactic reaction (IM or SQ)
Counteracts bronchoconstriction and suppresses glottal edema. Will help to ↑ BP and ↑Cardiac output.
Considerations: Contraindicated if pt is taking MAOI. Requires continuous monitoring when given IV, do not leave pt alone. If given for anaphylaxis pt should get immediate medical attention.
AEs: Dysrhythmias, angina, HTN, hyperglycemia, tremor, necrosis
7 classes of anti-HTN drugs
- Adrenergic antagonists (Alpha 1 blockers, Beta blockers, combo Alpha & Beta blockers)
- Centrally acting Alpha 2 agonists
- Angiotensin converting enzyme inhibitors (ACEIs)
- Angiotensin II receptor blockers (ARBs)
- Aldosterone inhibitors
- Calcium channel blockers (CCBs)
- Direct-acting vasodilators
prazosin (Minipress)
Class: Alpha 1 adrenergic antagonist
MoA: Selective Alpha 1 blockade causes dilation of arterioles and veins
Uses: HTN, benign prostatic hyperplasia
Considerations: long term use or high doses can cause Na+ and fluid retention, may need diuretic too. Take at bedtime to avoid O-HTN
AEs: Orthostatic hypotension, reflex tachycardia, ejaculation inhibition, nasal congestion. 1st dose or increased dose phenomenon–incr. r/f orthostatic hypotension, palpitations & dizziness 1-3h after dose.
ends in -zosin
alpha 1 blocker
ends in -pril
ACE inhibitor
ends in -sartan
Angiotensin II receptor blocker (ARB)
ends in -dipine
Ca2+ channel blocker mainly used to treat HTN (dihydropyridines)
propranolol (Inderal)
Class: 1st generation, non-selective beta blocker
MoA: beta 1 blockade: decreased HR, contractility, conduction resulting in decreased cardiac output and suppression of renin secretion. beta 2 blockade: bronchoconstriction, vasoconstriction, decreased glycogenolysis
Uses: HTN, angina, supraventricular tachydysrhythmias, MI, migraine, anxiety
Considerations: Caution w/ asthma & COPD (bronchoconstriction), can be hazardous for pts w anaphylactic allergies as it blocks epi, not recommended for pts w/ diabetes d/t masking symptoms of hypoglycemia & suppression glycogenolysis. Interacts w/ CCBs: excessive cardiac suppression. Contraindicated w/ preexisting HF, hold if on epi, norepi, dopamine or dobutamine IV.
AEs: Bradycardia, hypotension, heart block, HF, rebound tachycardia and arrhythmia with rapid withdrawal, rarely depression, hallucinations, insomnia.
metoprolol (Lopressor)
Class: 2nd generation selective beta 1 blocker
MoA: beta 1 blockade: decreased HR, contractility, conduction resulting in decreased cardiac output and suppression of renin
Uses: HTN, angina, HF, MI. preferred for pts w/ asthma/COPD or diabetes.
Considerations: Interacts w/ CCBs, counteracts beta agonist drugs such as epi, norepi, dobutamine, dopamine.
AEs: bradycardia, AV block, rebound tachycardia with rapid withdrawal, HD.
carvedilol (Coreg)
Class: 3rd gen selective alpha 1, beta 1 & beta 2 blocker.
MoA: selective beta + alpha 1 blocker: Adds add’l effect of vasodilation, decreasing afterload.
Uses: HTN, MI, angina
Considerations & AEs: same as other alpha 1 and beta blockers.
clonidine (Catapres)
Class: Centrally acting Alpha 2 agonist
MoA: acts in CNS to selectively activate alpha 2 receptor which suppresses NE release, resulting in decreased sympathetic stimulation of vessels and heart, causing bradycardia & vasodilation
Uses: HTN, severe pain relief, ADHD, many off label uses
Considerations: there is a transdermal patch and is given epidural for severe pain. CNS depressants and antihistamines will increase sedation. Contraindicated with pregnancy. Abuse potential w/ high doses: intensifies cocaine, benzos & opioids.
AEs: Drowsiness and dry mouth very common, decrease over time. Rebound HTN if withdrawn abruptly. NO O-HTN.
