Prototype Drugs Exam 1 Flashcards
Alpha- and Beta- Adrenergic Agonist
Dopamine (Intropin)
Indications for Dopamine
Correction of hemodynamic imbalances present in shock.
Actions of Dopamine
Acts directly and by the release of norepinephrine from sympathetic nerve terminals; mediates dilation of vessels in the renal and splanchnic beds to maintain renal perfusion while stimulating the sympathetic response.
Pharmocokinetics of Dopamine
Route: IV
Onset: 1-2 min
Peak: 10 min
Duration: Length of infusion
Half-life of Dopamine
2 min; metabolized in the liver, excreted in the urine.
Adverse Effects of Dopamine
Tachycardia, ectopic beats, anginal pain, hypotension, dyspnea, nausea, vomiting, headache.
Beta- specific adrenergic agonists
Isoproterenol (Isuprel)
Indications for Isoproterenol
Management of bronchospasm during anesthesia; vasopressor during shock; adjunct in the management of cardiac standstill and arrest, as well as serious ventricular arrhythmias that require increased inotropic (contraction of the heart muscle) action.
Actions of isoproterenol
Acts on beta- adrenergic receptors to produce increased heart rate, positive inotropic effect, bronchodilation and vasodilation.
Pharmacokinetics of isoproterenol
Route: IV
Onset : immediate
Duration: 1-2 min
Half-life of isoproterenol
unknown; metabolized in the tissues
Adverse effects of isoproterenol
Restlessness, apprehension, anxiety, fear, cardiac arrhythmias, tachycardia, nausea, vomiting, heartburn, respiratory difficulties, coughing, pulmonary edema, sweating, pallor.
Alpha- specific adrenergic agonist
Phenylephrine (Neo-Synephrine)
Indications for phenylephrine
Treatment of vascular failure in shock or drug-induced hypotension; to overcome paroxysmal supraventricular tachycardia; to prolong spinal anesthesia; as a vasoconstrictor in regional anesthesia; to maintain blood pressure during anesthesia; topically for symptomatic relief of nasal congestion and as adjunctive therapy in middle ear infections; ophthalmically to dilate pupils and as a decongestant to provide temporary relief of eye irritation.
Actions of phenylephrine
Powerful postsynaptic alpha- adrenergic receptor stimulant causing vasoconstriction and raising systolic and diastolic blood pressure with little effect on the beta- receptors int the heart.
Pharmacokinetics of phenylephrine
Route: IV
Onset : immediate
Duration: 15 -20 min
Route: IM, SQ
Onset: 10-15 min
Duration: 30 -120 min
Route: topical
Onset: very little systemic absorption occurs
Half-life of phenylephrine
47 to 100 hours; metabolized in the tissues and liver; excreted in urine and bile.
Adverse effects of phenylephrine
Fear, anxiety, restlessness, headache, nausea, decreased urine formation, pallor
Nonselective adrenergic blocking agent
Labetalol (Normodyne, Trandate)
Indications of labetalol
Hypertension, alone or in combination with other drugs; off-label uses– control of blood pressure in pheochromocytoma, clonidine-withdrawal hypertension.
Actions of labetalol
Competitively blocks alpha- and beta- receptor sites in the sympathetic nervous system, leading to lower blood pressure without reflex tachycardia and decrease renin levels.
Pharmacokinetics of labetalol
Route Oral IV
Onset. Varies. Immediate
Peak 1-2 h. 5 min
Duration 8-12h. 5.5 h
Half-life of labetalol
6-8 hours, with hepatic metabolism and excretion in the urine.
Adverse effects of labetalol
dizziness, vertigo, fatigue, gastric pain, flatulence, impotence, bronchospasm, dyspnea, cough, decreased exercise tolerance.
Nonselective alpha- adrenergic blocking agents.
Phentolamine (Regitine)
Indications for phentolamine
Prevention or control of hypertensive episodes associated with pheochromocytoma; prevention and treatment of dermal necrosis and sloughing associated with IV extravasation of norephinephrine or dopamine.
Actions of phentolamine
Competitively blocks postsynaptic alpha 1 and presynaptic alpha 2 receptors, causing vasodilation and lowering of blood pressure, accompanied by increased reflex tachycardia.
Pharmacokinetics of phentolamine
Route IM IV
Onset Rapid. Immediate
Peak 20 min. 2 min
Duration- 30-45 min. 15-30 min
Half-life of phentolamine
Metabolism and excretion are unknown
Adverse effects of phentolamine
Acute and prolonged hypotensive episodes, MI tachycardia, arrhythmias, nausea, flushing.
Nonselective beta- adrenergic blocking agent
Propranolol (Inderal)
Indications for propranolol
Treatment of hypertension, angina pectoris, IHSS (idiopathic hypertropic subaortic stenosis), supraventricular tachycardia, tremor; prevention of reinfarction after MI; adjunctive therapy in pheochromocytoma; prophylaxis of migraine headache; management of situational anxiety.
Actions of propranolol
competitively blocks beta- adrenergic receptors in the heart and juxtaglomerular apparatus; reduces vascular tone in the CNS.
Pharmacokinetics of propranolol
Route : Oral IV
Onset : 20- 30 min Immediate
Peak : 60- 90 min 1 min
Duration : 6-12 h 4-6 h
Half-life of propranolol
3-5 hours with hepatic metabolism and excretion in the urine.
Adverse effects of propranolol
allergic reaction, bradycardia, CHF, cardiac arrhythmias, CVA, pulmonary edema, gastric pain, flatulence, impotence, decreased exercise tolerances, bronchospasm
Alpha 1 selective adrenergic blocking agent
Doxazosin
Indications for doxazosin
treat HTN, and BPH
action of doxazosin
blocks alpha 1 receptor sites causing vasodilation
adverse effects doxazosin
dizziness, weakness, fatigue N/V, abdominal pain, diarrhea, edema, arrhythmias, hypotension, CHF, angina
D2D interactions of doxazosin
vasodilators or antihypertensive drug
beta 1 selective adrenergic blocking agents
atenolol
indications for atenolol
control HTN in pts who smoke, have asthma, COPD, seasonal or allergic rhinitis. Used to treat HTN, angina and some cardiac arrhythmias
Action of atenolol
blocks beta 1 adrenergic receptors, decreasing the excitablity of the heart, cardiac output, and oxygen consumption; decreases renin release, which lowers blood pressure.
Pharmo atenolol
Oral, IV route
varies, immediate onset
2-4 hr, 5 min peak
24hr duration
Half-life atenolol
6-7 hr, excreted in the bile, feces and urine
Adverse effects of atenolol
allergic rxn, dizziness, bradycardia, CHF, arrhythmias, gastric pain, flatulence, impotence, bronchospasm, decreased exercise tolerance
