INS and obesity due to melanocortin 4 receptor deficiency: Several classes of medicines have been used for pharmacological treatment of obesity, including those that limit nutrient absorption (e.g., orlistat); insulin sensitizers and suppressors (e.g., metformin, octreotide, exenatide); anorectic agents (e.g., sibutramine, leptin, phentermine, benzphetamine); and other stimulants (e.g., thyroid hormone, dinitrophenol, amphetamine, fenfluramine, dexfenfluramine, phenylpropanolamine).