para-Methoxy-N-methylamphetamine (PMMA; Methyl-MA), also known as 4-methoxy-N-methylamphetamine (4-MMA), is a stimulant and psychedelic drug closely related to the amphetamine-class serotonergic drug para-methoxyamphetamine (PMA). PMMA is the 4-methoxy analog of methamphetamine. Little is known about the pharmacological properties, metabolism, and toxicity of PMMA; because of its structural similarity to PMA, which has known toxicity in humans, it is thought to have considerable potential to cause harmful side effects or death in overdose. In the early 2010s, a number of deaths in users of the drug ecstasy were linked to misrepresented tablets and capsules of PMMA.
Its effects in humans are reputedly similar to those of PMA, but slightly more empathogenic in nature. It has a reduced tendency to produce severe hyperthermia at low dosages, but at higher dosages side effects and risk of death becomes similar to those of PMA.
The synthesis and effects of PMMA were described by American experimental chemist Alexander Shulgin in his book PiHKAL, where it is referred to by the name "Methyl-MA", as the n-methylated form of 4-MA (PMA). Shulgin reported that PMMA produces an increase in blood pressure and in heart rate, at doses above 100 mg, but causes no psychoactive effects at these levels.
PMMA has been found in tablets and capsules of the MDMA sold as "ecstasy". A number of deaths have been attributed to tablets sold as ecstasy that contained other substances, such as PMMA's structural analog, PMA. Death can occur when an ecstasy user believes they are consuming recreational doses of MDMA, when they are in fact consuming a lethal dose of another substance with similar effects. PMA is of particular concern because it not only causes a release of serotonin but also acts as a monoamine oxidase inhibitor (MAOI); if it is used in combination with MDMA or another MDMA-like substance, serotonin syndrome can result.
PMMA can be detected with pill testing kits.
In January 2011, the Norwegian Broadcasting Corporation reported that Norway had seen 12 deaths related to PMMA over the course of 6 months. In March 2011, Dutch media reported that there had been 4 deaths in the province of Limburg since November 2010. In April 2011, Icelandic media reported the death of a young woman that may have been connected to PMMA.
In 2011 alone, 4 deaths were recorded in Scotland as a result of ecstasy tablets which also contained PMMA.
In December 2012 and January 2013, several deaths linked to PMMA in the UK.
In June 2013 a PMMA-related death occurred in the Dutch city of 's-Hertogenbosch. Two months later, In August 2013, another possibly PMMA-related death occurred in the nearby town of Sliedrecht.  
Hong Kong newspaper Sing Tao Daily reports on 8th July 2013 that PMMA, called "Happy Powder" in the colloquial slang, is being used as a date-rape drug, being in the form of a flavoured soluble tablet that is undetectable by the human palate. 
- para-Methoxyamphetamine (PMA)
- 2-Methoxymethamphetamine (Methoxyphenamine)
- 3-Methoxymethamphetamine (MMMA)
- 4-Fluoromethamphetamine (4-FMA)
- 4-Methylmethamphetamine (4-MMA)
- 4-Methoxymethcathinone (bk-PMMA)
- Methyl-MA entry in PiHKAL
- Methyl-MA entry in PiHKAL • info
- Dutch article by TRIMBOS institute from 31-03-2011
- Icelandic arictle by Mbl news(Mbl.is) from 30-04-2011