Fatalities recreational

Fitzgerald RE, Fishel CE, Bush LLE Fatality due to recreational use of chlorodifluo-romethane and chloropentafluoroethane. J... 

A fatal interaction between ritonavir and MDMA (methylenedioxymethamphetamine, ecstasy) has been reported in an HIV-positive man (see Henry et ah, 1998). The patient had allegedly taken MDMA on several occasions without untoward effects. However, several weeks after ritonavir was added to his regular medication with zidovudine and lamivudine, he took some MDMA for recreational purposes and died of a cardiorespiratory arrest within hours. Toxicology showed that the plasma MDMA concentration was about ten times that expected from the ingested dose. Inhibition of CYP2D6, the principal pathway for MDMA metabolism, by ritonavir was thought to be the most likely cause. 

Nitric oxide formed from amyl nitrite inhibits cytochrome P450 (117) and ritonavir inhibits CYP2D6 (118), which has a major role in metamfetamine detoxification (119). This interaction could have led to fatal plasma concentrations of metamfetamine. It is therefore suggested that patients who take protease inhibitors are made aware of the potential risk of using any form of recreational drugs metabolized by CYP2D6, particularly metamfetamine. 

Methocarbamol is available by either prescription or as an over-the-counter product, often in combination with analgesics (acetylsalicylic acid, acetaminophen, codeine). It appears to be a relatively safe drug, one which is well-tolerated and widely used. Nevertheless, cases of fatal intoxication have been reported35-73-80 and a potential for abuse has also been evaluated in individuals with a history of recreational substance abuse81 -82. 

---