2020 年 46 巻 2 号 p. 77-83
We report the case of a 19-year-old woman with severe idiopathic pulmonary arterial hypertension who had been treated with upfront triple combination therapy comprising macitentan, tadalafil, and intravenous epoprostenol (EPO). One and a half years after the initiation of combination therapy, when EPO was increased to 18.87 ng/kg/min, mean pulmonary arterial pressure (mPAP) and cardiac index (CI) significantly improved from 40 to 19 mmHg and from 4.11 to 2.43 L/min/m2, respectively. After normalization of pulmonary hemodynamics, we decided to switch the prostacyclin pathway drug from EPO to oral selexipag. When selexipag was increased to 800 μg/day, she presented with significant nausea and headache. After simultaneous administration of metoclopramide (5 mg) and acetaminophen (200 mg) as estimated by maximum blood concentration of an active metabolite of selexipag, she could finally tolerate 3,200 µg/day selexipag. EPO was tapered off after careful observation for potential clinical worsening. Eight months after weaning from EPO, her pulmonary hemodynamics remained within the near-normal range as evidenced by mPAP (21 mmHg) and CI (4.45 L/min/m2), indicating the short-term success of switching from EPO to selexipag. In conclusion, effective management of side effects by pharmacists according to the pharmacokinetics of selexipag and its metabolites resulted in restoring the side effects, enabling us to increase selexipag to its maximum dosage. Consequently, EPO was successfully switched to oral selexipag with improved activity in daily life. There have been no reports on the transition from EPO to selexipag, and we report the first case.
