Propiram

Propiram (Algeril, Dirame, Bay 4503) is a partial mu opioid receptor agonist and weak mu antagonist analgesic from the ampromide family of drugs. It was invented in 1963 in the United Kingdom by Bayer but was not widely marketed, although it saw some limited clinical use, especially in dentistry. A report in the reference Drug Facts & Comparisons, 56th (2002) Edition reports that research about the drug has increased in the past few years, having reached the (albeit restricted) Stage III clinical trial process in the United States and Canada. Propiram is currently a Schedule I/Narcotic controlled substance in the United States with an ACSCN of 9649 and a zero annual aggregate manufacturing quota as of 2014. It has been almost exclusively used as the fumarate salt, which has a free base conversion ratio of 0.70.