Showing posts with label adrenergic blockers. Show all posts
Showing posts with label adrenergic blockers. Show all posts
- competitively block beta receptors in SNS
- its therapeutic effects caused by beta-block in heart & juxtaglomerular apparatus
- (-) inotrope, (-) chronotrope, (-) dromotope
- this leads to ↓ arrhythmia, ↓ cardiac workload, ↓ O2 consumption
- & dec BP b/c juxtaglomerular cells not stimulated to secrete renin
- drugs ending in -olol
Indications
- Tx cardiac conditions – HTN, angina, migraine headaches, preventing re-infarction after MI
- off label: anxiety/stage fright
Contraindications
- brady, heart block, shock, CHF
- COPD/asthma (blocks dilation)
Cautions
- diabetes (blocks normal S&S of hyper-/hypoglycemia)
- thyrotoxicosis (b/c blocking effects on thyroid gland)
- hepatic dysfunction
Adverse Effects
- brady, heart block, hypotension, arrhythmia, HF
- bronchospasm, cough
- fatigue, dizziness
- sleep disturbance, depression
- N/V, diarrhea
- ↓ labido, dysuria
- ↓ exercise tolerance / can no longer "get-up-and-go"
Kinetics
- Well absorbed from GI tract
- Metabolized in the liver
Drugs
1. Propranolol (Inderal)
- Patient teaching required:
- teach pt to take pulse / take pulse before taking med
- teach pt it blocks S&S hypoglycemia
- teach about compliance &
- teach that abrupt d/c can lead to withdrawal syndrome (tremors, sweating, headache, malaise, palpitation, rebound HTN, MI, life-threatening arrhythmia)
- teach about postural hypotension
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2. Sotalol (Betapace)- indicated for life-threatening arrhythmia & maintenance of sinus rhythm w/ AF or a-fib pt
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Drug Interactions
- ↓ effectiveness w/ NSAIDs
- blood glucose changes w/ diabetic meds & insulin
- HTN may occur if given w/ clonidine
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Nursing Mgmt for Nonselective Beta Blockers- if used LT, do not stop abruptly! (receptors become hypersensitive to catecholamines) – can cause rapid inc BP → MI / stroke
- should taper over 2wks
- labs: liver/kidney function, thyroid function, blood glucose
Nonselective Beta Blockers
- These work on alpha receptors
- vasodilates aka ↓ BP (alpha 1)
- & blocks NE feedback control (alpha 2)
Indications
- primarily used to prevent cell death/tissue sloughing r/t IV DA or NE extravasation/infiltration (causes local vasodilation & return of blood flow to the area)
- can be used for pheochromocytoma Dx or mgmt of severe HTN reactions s/p pheochromocytoma surgery
CAD or MI
Nonselective Alpha Blockers
- These are non-selective drugs.
- competitively block norepinephrine at alpha & beta receptors
- called sympatholytic drugs b/c they lyse or block SNS effects to prevent S&S associated w/ sympathetic stress reaction
- ↓ HR & ↓ BP
- ↑ renal perfusion & ↓ renin levels
Indications
- primarily used to treat cardiac conditions i.e essential HTN (usually adjunct w/ diuretics)
Contraindications
- brady or heart block
- shock or CHF
- pregnancy & lactation
Cautions
- bronchospasm & resp distress
- (due to loss of NE bronchodilation effects)
Adverse Effects
- arrhythmia, hypotension, CHF
- pulm edema, bronchospasm, dyspnea
- dizziness, vertigo
- insomnia, fatigue
- N/V, gastric pain
Kinetics
- Well absorbed
- Metabolized in the liver and excreted in the urine & feces
Drugs
1. Amiodarone (Cordarone)
- antiarrhythmic agent
- reserved for emergency use
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2. Carvedilol (Coreg)- indicated for HF, MI, HTN, left ventricle dysfunction
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3. Labetalol (Normodyne)- indicated for HTN
- control of BP in pheochromocytoma
- used for clonidine withdrawal HTN
Nursing Mgmt for All A&B Agonists
- monitor diabetic pt closely: these drugs also mask S&S hypoglycemic & hyperglycemia
- priority for diabetic pt is to monitor glucose over pulse; priority for most pt on adrenergic blockers is to monitor pulse
- monitor vitals + blood glucose + liver/kidney function
- educate pt about AE, re-educate diabetics about glucose monitoring
- find out pt herbal drug use:
- Ginseng = ↑ anti-HTN effects (risk hypotension, CNS effects)
- Xuan shen, nightshade = ↓ HR (risk severe brady, reflex tachy)
- Celery, Xuan shen, coriander = ↓ glucose (inc risk hypoglycemia)
- Saw palmetto = ↑ risk urinary tract complications
Nonselective Alpha & Beta Blockers
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