Explain Phenylephine and Methoxamine in amyl nitrite ?
They have opposing effects to amyl nitrite as they increase the systemic BP. phenylephine due to its shorter duration of action is preferred. Both cause reflex bradycardia and reduced contractility and cardiac output. Both are given intravenously, with elevation of BP lasting for 3-5 minutes with methoxamine. These agents should not be used in patients with systemic hypertension or those in CHF.