Introduced as an analgesic in the 1930s, meperidine produces effects that are similar, but not identical, to morphine (shorter duration of action and reduced antitussive and antidiarrheal actions). Currently it is used for pre-anesthesia and the relief of moderate to severe pain, particularly in obstetrics and post-operative situations. Meperidine is available in tablets, syrups, and injectable forms under generic and brand name (Demerol®, Mepergan®, etc.) Schedule II preparations. Several analogues of meperidine have been clandestinely produced. During the clandestine synthesis of the analogue MPPP, a neurotoxic by-product (MPTP) was produced. A number of individuals who consumed the MPPP-MPTP preparation developed an irreversible Parkinsonian-like syndrome. It was later found that MPTP destroys the same neurons as those damaged in the Parkinsonian-like syndrome. It was later found that MPTP destroys the same neurons as those damaged in Parkinsons Disease.