This section covers drugs used in management of obesity (such as orlistat and sibutramine) as well as older drugs, such as amfetamines, which are now no longer widely indicated for this condition, and are now more generally considered as drugs of abuse. However, it should not be forgotten that amfetamines (largely dexamfetamine) still have a limited therapeutic role in management of narcolepsy. Ecstasy (MDMA,methylenedioxymethamfetamine), a drug of abuse that is structurally related to amfetamine, is also included in this section. The amfetamines are sympathomimetics,a diverse group, which have a number of interactions. The mechanism of action and classification of sympathomimetics is discussed in Cardiovascular drugs,miscellaneous, . Other stimulant drugs (such as atomoxetine; and methylphenidate,another sympathomimetic) have a role in attention deficit hyperactivity disorder (ADHD) and are also discussed in this section.