Vasopressin

Synthetic arginine vasopressin copies the endogenous antidiuretic hormone that conserves water and, at higher activity, constricts blood vessels. Vasostrict is used to support dangerously low blood pressure in critical care. Earlier clinical use preceded the first fully FDA-approved vasopressin injection in 2014.

V1a receptors on vascular smooth muscle mediate vessel contraction, increased systemic vascular resistance and higher pressure. Kidney V2 receptors promote water reabsorption. The vascular pathway differs from norepinephrine and other catecholamine vasopressors, allowing additional support when their effect is inadequate or their receptors respond less well.

In septic or other vasodilatory shock, this helps restore abnormally reduced vascular tone. Pressure support should not be mistaken for a demonstrated survival advantage: VASST found that adding low-dose vasopressin to norepinephrine did not reduce overall 28-day mortality versus norepinephrine alone. A less-severe-shock subgroup suggested possible benefit. Clinical use supports pressure and may reduce other vasopressor requirements.

FDA approved Vasostrict in 2014 to raise blood pressure in adults with vasodilatory shock and persistent hypotension despite fluids and catecholamines. It is delivered as a continuous intravenous infusion under close monitoring.

Uses include inadequately responsive septic or post-cardiotomy vasodilatory shock after fluid resuscitation and catecholamine treatment. This is an intensive-care medication, not an outpatient wellness treatment.

Adverse effects include reduced cardiac output, bradycardia or arrhythmias. Excess vasoconstriction can reduce blood supply to the heart, intestine, digits or skin and cause tissue damage. Hyponatremia can occur, and leakage outside the vein may injure surrounding tissue.