The Mayo Clinic website has a list of commonly used Food and Drug Administration-approved weight loss drugs, and others can be found by searching the FDA website. As of April 2015, the list of commonly used approved drugs includes Qsymia, Belviq and Orlistat.
Qsymia is a combination of two FDA-approved drugs, phentermine and topiramate, and it's used as an addition to a reduced-calorie diet and exercise, according to the FDA. The drug was approved in 2012, and it helps reduce appetite and increase the feeling of fullness. Side effects include insomnia, dry mouth, dizziness, constipation, and changes in sense of taste or smell, notes Mayo Clinic.
Belviq, or lorcaserin hydrochloride, is a drug that activates the serotonin 2C receptor in the brain, which helps a person eat less and feel full after eating smaller amounts of food, according to the FDA. The drug was also approved in 2012 and has side effects such as headache, nausea, dry mouth, dizziness, fatigue and constipation, states Mayo Clinic.
Orlistat, or xenical, is a drug that stops the absorption of fat in the body, which, in turn, reduces the amount of calories taken in, according to the FDA. The drug was approved in 1999 as a prescription medication and was approved in 2007 as an over-the-counter medication called Alli. Some side effects include decreased absorption of fat-soluble vitamins, oily spotting, intestinal cramps, gas with discharge and diarrhea, notes Mayo Clinic.