Chapter 30 - Adrenergic Agonists Flashcards
What are the Indications and Actions of Dopamine?
Indications: Correction of hemodynamic imbalances present in shock.
Actions: Acts directly and by the release of norepinephrine from sympathetic nerve terminals. Mediates dilation of vessels to maintain renal perfusion while stimulating sympathetic response.
What are some adverse effects of dopamine?
Tachycardia Ectopic beats (skipping) Anginal pain (chest) Hypotension Dyspnea Nausea & vomiting Headache
What are some indications of Phenylephrine?
1) Treatment of vascular failure in shock or drug induced hypertension
2) Overcome paroxysmal SVT
3) Symptomatic relief of nasal congestion
4) Therapy for middle ear infections
5) Pupil dilation
What are the actions and adverse effects of Phenylephrine?
Actions: powerful post synaptic alpha adrenergic receptor stimulant causing vasoconstriction. Raising systolic & diastolic BP with little effect on beta receptors in the heart.
Adverse: fear, anxiety, restlessness, headache, nausea, decreased urine formation, pallor
What are some indications of isoproterenol? (Isuprel)
Treatment of shock, cardiac arrest, and certain ventricular arrhythmias; treatment of heartblock in transplanted hearts; treatment of bronchospasm during anesthesia. (P.497)
What are some actions and adverse effects of isoproterenol? (Isuprel)
Acts on beta-adrenergic receptors to produce increased heart rate, positive inotropic effect, bronchodilation, and vasodilation.
Adverse: restlessness, apprehension, anxiety, fear, cardiac arrhythmias, tachycardia, nausea, vomiting. (P.498 for more)
What is a sympathomimetic and how do they produce effects?
A drug that mimics the effects of the sympathetic nervous system (SNS).
The drugs produce therapeutic and adverse effects by their stimulation of adrenergic receptor sites either direct (occupation of receptor) or indirect (neurotransmitter) stimulation. p. 486
Sympathomimetic drugs can be divided into which categories?
Alpha agonists:
a1 = blood vessels a2= nerves
Beta agonists;
b1= cardiac b2= lungs/"everything else"
What are the actions and indications of a/b adrenergic agonists?
1) Heart rate increases with increased myocardial contractility.
2) bronchi dilate
3) respiration a increase in rate and depth
4) blood vessels constrict increases BP
5) intraocular pressure decreases
6) pupils dilate
What are indications of labetalol?
1) Hypertension
Off label:
Control of BP in pheochromocytoma
Clonidine withdrawal hypertension
What are the actions of labetalol
Competitively blocks alpha and beta receptor sites in the in the SNS leading to lower BP without reflex tachycardia and decreased renin levels.
Adverse effects of labetalol?
Dizziness, vertigo, fatigue, gastric pain, flatulence, impotence, bronchospasm, dyspnea, cough, decrease exercise tolerance
What are indications of phentolamine?
Prevention or control of hypertensive episodes associated with pheochromocytoma; test for diagnosis; prevention and treatment of dermal necrosis and sloughing with IV extravasation of norepinephrine or dopamine.
What are the actions of phentolamine?
Competitively blocks postsynaptic alpha 1 and presynaptic alpha 2 receptors, causing a vasodilation and lowering BP, accompanied by increased reflex tachycardia.
Adverse effects of phentolamine?
Acute and prolonged hypotensive episodes, MI tachycardia, arrhythmias, nausea, flushing
What are indications of doxazosin?
Treatment of hypertension as monotherapy or in combo antihypertensive drugs;
Treatment of benign prostatic hypertrophy
Effects of Doxazosin?
Reduces total peripheral resistance through alpha blockade
Does not affect HR or CO
Increase high density lipoproteins while lowering total cholesterol levels
Adverse effects of doxazosin?
Headache Dyspepsia Fatigue Dizziness Postural Dizziness Vertigo Tachycardia (p 509)
Propranolol indications?
Treatment of hypotension
Angina pectoris
Idiopathic hypertrophic subaortic stenosis
SVA
Prevention of heart attack after already having one
Adjunctive therapy in pheochromocytoma
Actions of Propranolol?
Competitively blocks beta adrenergic receptors in the heart and juxtaglomerular apparatus; reduces vascular tone in CNS
Adverse effects of propranolol
Allergic reaction Bronchospasm Bradycardia Heart failure Cardiac arrhythmias CVA Pulmonary edema Gastric pain
What are some indications of atenolol?
Treatment of angina Hypertension MI Off label: Prevention of migraines Alcohol withdrawals SVT
Actions of atenolol?
Blocks beta 1 adrenergic receptors
Decreasing the excitability of the heart
Cardiac output and O2 consumption
Decreases renin release
Adverse effects of atenolol??
Allergic reaction Dizziness Bradycardia Heart failure Arrhythmias Gastric pain Flatulence Impotence Bronchospasm Decreased exercise tolerance
