Loperamide 1980s, prior to the expiration of US patent on 30 January 1990, McNeil company started to develop Imodium Advanced containing loperamide and simethicone for treating both diarrhea and gas. In March 1997, the company patented such combination. The drug was approved in June 1997 by the FDA as Imodium Multi-Symptom Relief in the form of a chewable tablet. In November 1993, loperamide was launched as an orally disintegrating tablet based on Zydis technology. Imodium Instant Melts from Johnson & Johnson is currently the only loperamide available in the form of orally disintegrating tablets. In 2013, loperamide in the form of
Loperamide first-pass metabolism by the liver. Loperamide metabolizes into an MPTP-like compound, but is unlikely to exert neurotoxicity. Efflux by P-glycoprotein also prevents circulating loperamide from effectively crossing the blood–brain barrier, so it can generally only antagonize muscarinic receptors in the peripheral nervous system, and currently has a score of 1 on the anticholinergic cognitive burden scale. Concurrent administration of P-glycoprotein inhibitors such as quinidine potentially allows loperamide to cross the blood–brain barrier and produce central morphine-like effects. Loperamide taken with quinidine was found to produce respiratory depression, indicative of central opioid action. Loperamide has been shown to cause a mild