PMMA

para-Methoxy-N-methylamphetamine (abbreviated PMMA and also known as Doctor Death) is a stimulant and psychedelic drug.

History
Very little is actually known about PMMA's pharmacological properties, metabolism, and toxicity. It has been assumed the drug is lethal since its structure and effects from usage are similar to another drug known as PMA, which is known to be toxic to humans. At low dosages, PMMA causes severe hypothermia, and at high dosages, there is a large risk of death. PMMA is often found in packages of MDMA that are sold as ecstasy. In the early to mid-2010s, over 30 deaths attributed to PMMA were reported in Western countries such as Great Britain, Canada, and Australia. The latest PMMA-related incident occurred in Great Britain on January 2015, when four people died after allegedly taking ecstasy pills containing PMMA; a man was charged for supplying the drugs.

On Criminal Minds
Poisoner Larry Feretich mixed PMMA with methamphetamine and used the mixture to kill his victims in Brothers Hotchner.