Pharmacology of tolazoline.

Tolazoline's complex pharmacologic effects likely represent the algebraic sum of primary, secondary, and possibly tertiary interactions with histamine and adrenergic receptors. Oxygenation improves initially in the majority of neonates with PPHN treated with tolazoline. Preliminary studies of tolazoline pharmacokinetics in the newborn indicate current doses are excessive and lead to accumulation, which may contribute to adverse effects, including cardiotoxicity.