Vasopressin in sepsis and septic shock.

Arginine vasopressin (AVP) and its synthetic, long-acting analog terlipressin (TP) are potent alternative vasoconstrictors in the treatment of septic patients with catecholamine-refractive vasodilatatory shock. The results from one large randomized clinical trial suggest that AVP plus norepinephrine (NE) infusion is as safe and effective as treatment with NE alone in patients with septic shock. Because the desired effects of vasopressin analogs are basically related to their vasopressinergic effects via the V1a receptor, more selective V1 agonists, such as TP, may be more potent in reversing sepsis-related arterial hypotension. In this regard, recent evidence from small-scale studies suggests that continuous low-dose infusion rather than intermittent bolus injection of TP is associated with fewer side effects, such as depression of cardiac output and rebound arterial hypotension. However, because clinical data on the administration of TP in patients with sepsis are limited, it should not currently be used beyond the scope of controlled trials. The optimal time point for the initiation of therapy with vasopressin analogs has yet to be determined. While AVP and TP are commonly used as last-resort therapies in severe septic shock, some evidence supports the initiation of treatment in a less severe state of the disease.