CYP3A4 and pulmonary arterial hypertension: After its activation to the reactive pyrrole metabolite dehydromonocrotaline (MCTP) in the liver via cytochrome P-450 (CYP3A4) it provokes the development of “MCT syndrome” manifested as acute lung injury interstitial pulmonary fibrosis, pulmonary hypertension with right ventricle hypertrophy and myocarditis [17, 18].