The haemodynamic effects of subcutaneous sumatriptan, a 5HT1-receptor agonist

Aims Previous in vivo studies with sumatriptan, a 5HT₁-receptor agonist, have demonstrated vasopressor responses in the pulmonary and systemic arterial circulation. Pulmonary artery wedge pressure (PAWP) also increases after sumatriptan injection, raising the possibility of an additional venoconstrictive action or a negative inotropic effect. The mechanism for the rise in PAWP was investigated in the study.
Methods Ten patients undergoing diagnostic coronary arteriography underwent haemodynamic monitoring.
Results There was a significant rise ( P <0.05) in systemic and pulmonary arterial pressure and total systemic and pulmonary vascular resistance. There was a similar rise ( P <0.05) in PAWP and left ventricular end diastolic pressure (LVEDP). There was no change in cardiac output nor in peak rate of left ventricular pressure rise (dP/dt).
Conclusions The sumatriptan induced rise in PAWP and LVEDP appears consequent upon increased afterload although a negative inotropic effect cannot be excluded.