The combination of phentermine with fenfluramine was once commonly employed in management of obesity. Phentermine reduces food intake by acting on β-adrenergic receptors in the perifornical hypothalamus (Bray, 1993). Fenfluramine and dexfenfluramine (the d-isomer of fenfluramine) increases the release of serotonin to suppress appetite and reduce food intake (Connolly et al., 1997). Both phentermine and fenfluramine were individually approved by the USFDA. However, both fenfluramine and dexfenfluramine were withdrawn from market by the USFDA in 1997 (Ioannides et al., 2006).
