VASOACTIVE DRUGS Flashcards
What is the mechanism of action of Ephedrine?
Stimulates both alpha and beta receptors directly and indirectly by releasing endogenous catecholamines.
What are the uses of Ephedrine?
Treats hypotension, especially in anesthesia-induced cardiac depression and vasodilation from spinal anesthesia. Also causes bronchodilation.
What is the dosage for Ephedrine?
IV: 5 - 25 mg (Not in watson’s slide)
What is the onset and duration of Ephedrine?
Onset: Immediate; Duration: 15 min - 1.5 hours
What are the cautions associated with Ephedrine?
Can dramatically increase myocardial oxygen consumption; use cautiously in coronary artery disease.
What is the mechanism of action of Phenylephrine?
Pure alpha agonist; increases peripheral vascular resistance via alpha 1 receptor activation, leading to increased blood pressure.
What are the uses of Phenylephrine?
Treats hypotension, nasal bleeding (topical use), mydriasis in ophthalmology, and OB hypotension after regional anesthesia.
What is the dosage for Phenylephrine?
IV push: 50-200 mcg; infusion: 0.2-2 mcg/kg/min (Not in Watson’s slide)
What is the onset and duration of Phenylephrine?
Onset: Immediate; Duration: 5-20 min
What are the cautions associated with Phenylephrine?
Reflex bradycardia is common due to baroreceptor stimulation.
What is the mechanism of action of Esmolol?
Beta-1 selective blocker; decreases heart rate, contractility, and AV conduction.
What are the uses of Esmolol?
Perioperative hypertension, tachycardia, and arrhythmias.
What is the dosage for Esmolol?
Bolus: 500 mcg/kg IV; Small bolus: 10-20 mg; Infusion: 100-300 mcg/kg/min
What is the onset and duration of Esmolol?
Onset: 2 min; Duration: 10-15 min
What is the elimination half-life of Esmolol?
9 min
What is the mechanism of action of Metoprolol?
Beta-1 selective blocker; negative chronotropic, dromotropic, and inotropic effects.
What are the uses of Metoprolol?
Perioperative hypertension, tachycardia, arrhythmias, post-MI, and angina.
What is the dosage for Metoprolol?
IV: 5 mg every 5 min, max dose 15 mg; Oral: 50-200 mg once or twice daily; Extended-release: 25-400 mg once daily
What is the mechanism of action of Labetalol?
Non-selective beta-blocker with alpha-blocking effects (7:1 ratio).
What are the uses of Labetalol?
Treats hypertension, particularly in obstetric patients (uterine blood flow is not affected).
What is the dosage for Labetalol?
IV push: 0.25 mg/kg, repeat every few minutes; Infusion: 2 mg/min
What is the duration of action for Labetalol?
2-6 hours
What is a caution associated with Labetalol?
Contraindicated in preexisting bradycardia.
