Anorectic It can promote weight loss when used for a short time. Controlled substance Can cause rapid or irregular heartbeat, delirium, panic, psychosis, and heart failure. Brands: Lomaira and Adipex-P Availability: Prescription needed Pregnancy: Consult a doctor Alcohol: Avoid. Very serious interactions can occur Phentermine (Adipex-P, Lomaira) is an amphetamine-like prescription medication used to suppress appetite. It can help weight loss by decreasing your hunger or making you feel full longer. Phentermine is also available in combination with topiramate for weight loss (Qsymia).