Polydrug abuse

Polydrug abuse refers to the use two or more psychoactive drugs in combination to achieve a particular effect. Often called "cross fading", it is usual among problem drug users who have a multi-drug dependence. In many cases one drug is used as a base-, primary- or preferred drug, with additional drugs to leaven or compensate for the side effects of the primary drug and make the experience more enjoyable with drug synergy effects, or to supplement for primary drug when supply is low.

The potentiating effect of one drug on another is sometimes considerable, and here the illicit drugs and medicines – such as alcohol, nicotine and antidepressants – have to be considered in conjunction with the controlled psychoactive substances. The risk level will depend on the dosage level of both substances. Concerns exist about a number of pharmacological pairings: alcohol and cocaine increase cardiovascular toxicity; alcohol or depressant drugs, when taken with opioids, lead to an increased risk of overdose; and opioids or cocaine taken with ecstasy or amphetamines also result in additional acute toxicity. The risk for aggression and violent outbursts increase when some benzodiazepines, for example Flunitrazepam, are combined with alcohol.

Within the general concept of multiple drug use, several specific meanings of the term must be considered. At one extreme is planned use. On the other hand, the use of several substances in an intensive and chaotic way, simultaneously or consecutively, in many cases each drug substituting for another according to availability.

There are many common drug combinations, including, but not limited to: Poly drug use often carries with it more risk than use of a single drug, due to an increase in side effects, and drug synergy.
 * tobacco and marijuana (inside a joint called a "spliff", or as a cigar wrapping stuffed with marijuana instead of tobacco, known as a "blunt")
 * marijuana and alcohol (referred to as a "green dragon")
 * alcohol and tobacco
 * tobacco and caffeine
 * alcohol and caffeine
 * marijuana and cocaine (known as chewy)
 * marijuana and coffee (known as "hippie speedball")
 * Mountain Dew mixed with spoonfuls of instant coffee (known as "prison speedball")
 * LSD and ecstasy (known as "candy flipping" )
 * Psychedelic mushrooms and ecstasy (known as "hippie flipping" or "flower flipping" )
 * dextromethorphan and marijuana
 * dextromethorphan and Psychedelic mushrooms ("cherry bombing")
 * ecstasy and LSD and Psychedelic mushrooms ("psycho flipping")
 * marijuana and Psychedelic mushrooms (the marijuana as an anti-nausea)
 * cocaine and heroin or morphine (known as a "speedball")
 * cocaine and ketamine (known as "CK1" )
 * ecstasy and viagra (known as "sextasy" or "purple rhino," refering to the extremely tenacious erection which often ensues)
 * ecstasy and ketamine (known as "kitty flipping" )
 * ecstasy and PCP (known as "elephant flipping" )
 * ecstasy and mescaline (known as "love flipping" )
 * heroin and diphenhydramine (known as "cheese")
 * marijuana and PCP (known as a "wet daddy")
 * crack and PCP (known as "space basing" )
 * amphetamines and barbiturates or benzodiazepines

The phenomenon is the subject of established academic literature (e.g., Scholey AB, Parrott AC, Buchanan T, Heffernan TM, Ling J, Rodgers J (2004). "Increased intensity of Ecstasy and polydrug use in the more experienced Ecstasy/MDMA users: a WWW study." Addictive Behaviors, 29, 743-752).