Vasopressin and terlipressin in neonates and children with refractory septic shock.

Vasopressin and its analogue terlipressin are potent vasopressors which have been recently proposed in the treatment of catecholamine-resistant septic shock. We review the physiology, metabolism and pharmacology of vasopressin and terlipressin, as well as the available data on their efficacy and safety in neonates and children with septic shock. In adults, vasopressin deficiency can contribute to refractory shock states associated with sepsis. Differently, in children with septic shock vasopressin levels may be normal or even augmented. Nevertheless, low doses of vasopressin and terlipressin seem to have the potential to restore vasomotor tone in conditions refractory to catecholamines, improving organ perfusion with preservation of renal blood flow, while decreasing catecholamine requirements. Vasopressin and terlipressin produce vasoconstriction via stimulation of V1-receptors. In particular, terlipressin has a higher selectivity for V1-receptors and a longer half-life when compared to vasopressin, allowing for intermittent bolus doses. However, the pharmacology of vasopressin/terlipressin in newborns and children has not been sufficiently investigated and data on potential short and long-term adverse effects are still lacking. Further clinical, pharmacokinetic and pharmacodynamic studies are needed to better define the role of vasopressin and terlipressin in septic shock, as well as to prove their effectiveness and safety in infants and children.