CYP2C9 and pulmonary hypertension, primary, 1: CYP2C9*3 is associated with SCARs by PHT (OR: 12.00; 95% CI: 2.759–84.87; p = 0.03).CYP2C9*3 and HLA-B*55:01 with SCARs (OR: 12.45; 95% CI: 1.138–136.2; p = 0.003) and maculopapular rash due to PHT (OR: 4.041; 95% CI: 1.125–15.67; p = 0.035). HLA-B*51:01/PHT-SCAR (OR: 6.273; 95% CI: 2.24–16.69; p = <0.001) and HLA B*51:01/PHT-SCARs (OR: 2.323; 95% CI: 1.22–5.899; p = 0.037).