L8 Flashcards
4 A1 blocker effects
- ↓BP
- Dilate eye
- Relax GU smooth muscle
- ↓Viscous salivation
3 A2 blocker effects
Blocks A2 autoreceptor that normally stops NE release
- ↑NE - sympathetic effects (↑HR)
- ↑Insulin
- ↑GI motility
What are the effects of non-selective A1 & A2 block?
A1 block effects
+
B effects - ↑NE release (tachycardia, etc)
What kind of drugs are ergot alkaloids? Name 2.
Partial A1 and serotonin agonists
From infected grains
1. Ergotamine
2. Ergonovine
Use ergotamine
Vasoconstrict to abort migraine headaches
Use ergonovine
W/ oxytocin
Vasoconstrict POST-partum uterus -> prevent hemorrhage
What is ergotism?
Too much ergot in system
Vasospasm -> painful limbs -> peripheral gangrene
What are the 2 A1 & 2 non-selective blockers? What are the differences between them?
- Phenoxybenzamine
- Irreversible
- Long acting - Phentolamine
- Competitve
- Short acting
Major use of A1 & 2 non-selective blockers
Before/during surgical resection of catecholamine secreting tumors
(1st alpha block, 2nd beta)
Do you use A1/2 non selective blockers to manage 1ary HTN?
NO
3 uses of prazosin and terazosin
A1 blockers
- 1ary HTN but not 1st line
- Vasodilate for peripheral vasc diseases
- Relax urinary smooth muscle
- Pee out kidney stones
How does tamsulosin act differently than other A1 blockers?
A1a specific - in vascular smooth muscle most A receptor are b type
- Doesn’t change BP as much
Selectively relaxes urinary tract smooth muscle
Pathophys of benign prostatic hyperplasia - what can you use to treat it
Causes constriction of upper urethra –> incomplete bladder emptying –> ↑urinary freq
Use any of the A1 blockers
7 adverse effects of A1 blockers
- Postural hypotension - try to take meds at bedtime
- Nasal congestion since dilating
- Intraop floppy iris syndrome since relaxing smooth muscle of iris, avoid these drugs pre-cataract surg
- Retrograde ejaculation
- Delayed ejaculation
- Priapism = sustained, painful erection
- Dry mouth
Explain sympa activity vs A blocker activity at erectile tissue
Sympa = bind A receptor - contract vascular & trabecular smooth muscle –> faccid
A blocker = dilate smooth muscle –> ↑blood flow & collapse veins - erection
What are the expected cardiac outcomes of B blockers?
↓HR, CO
↓O2 demand
↓AV conduction velocity
Effects of B blockers on electrolytes
Hypoglycemia
Hyperkalemia
Other effects of B blockers
↓Renin Vasoconstriction Bronchoconstriction ↓Tremors since ↑K uptake into muscle = muscle weakness ↑Mast cell degranulation
5 CV indications to use B blockers
Angina of effort Post-infarction Arrhythmias Systolic HF 1ary HTN
Which thyroid condition means you can use B blockers
Hyperthyroidism - short term management
Why use B blockers for glaucoma?
↓Aqueous inflow –> ↓IOP
Use topically
How would you take B blockers for migraines?
Prophylactic
Adverse CV effects of B blockers
↓Exercise capacity
Bradycardia
AV conduction block
Exacerbate HR
Peripheral vasoconstriciton = cold extremities
Withdraw B super sensitivity - ↑ed risk for CAD pts
Non-CV adverse effects of B block
- Asthma/COPD bronchoconstriction
- Mast cell destablize via B2 receptors - don’t use E to manage anaphylaxis
- Blunted signs or delayed recovery of hypoglycemia - don’t get the responsive sympo-adrenal discharge
- Exercise induced hyperkalemia as B2 ↑s K uptake in skeletal muscle –> weakness
What do you need to worry about with topical B blocker application?
Getting into systemic circulation
If a pt has a condition of adrenergic excess, what can result from use of B blockers?
Hypertensive emergency
What is the difference between high and low lipid soluble beta blockers?
- How excreted
- Membrane crossing
High = eliminated by liver metabolism, crosses BBB & placenta Low = renal excretion
Which pts would greatly benefit from use of partial B agonists?
Bradycardia
Partial conduction block
What is the major advantage of using a B1 selective blocker?
Leave B2 alone = less risk non-CV adverse events
As you increase B1 selective blocker dose, this benefit decreases
Which B blocker is used in eye drops?
Timolol = noselective blocker
What are 2 B1 selective blockers?
Atenolol
Metoprolol
What are 2 non-selective B blockers with additional vasodilator actions?
Carvedilol
Labetalol - alpha1 and B blocker
What is the body’s response to BB given IV in an acute setting?
↓↓CO
↑TPR
- Not due to B2 block, due to reflex vasocontriction post ↓CO
No change BP
What is the body’s response to BB given PO over a longer period of time?
↓TPR –> ↓BP
- Not secondary to ↓CO - independent
- Doesn’t bring you back to baseline, residual vasoconstriction means pts will complain of cold extremities
Which BB is used in heart failure to prevent myocyte cell death? Mechanism?
Carevdilol
Signals through B arretins -> inhibits apoptosis -> ↑cardiomyocyte survival
2 uses of B2 blockers
Chronic glaucoma - ↓aqueous inflow
↓tremors
