HTR2B and heart valve disorder: FFA was reported to induce valvular heart disease and pulmonary arterial hypertension, potentially due to 5-HT2B stimulation (Rothman et al., 2000); however, these effects were most likely related to high dosages (up to 160 mg/day), combination treatment with other 5-HT2B agonists (such as phentermine), and/or other cardiovascular risk factors (older age/female sex/hypertension) (Rothman et al., 2000).