Polydrug use (or polysubstance use) refers to the use of combined psychoactive substances to achieve a particular effect. In many cases, one drug is used as the base or primary drug, with additional drugs to mitigate or offset the side effects of the primary drug and make the experience more pleasurable.
When two or more drugs are used together, their effects can be additive (the result is what you expect when you add up the effect of each drug separately (1+1 = 2), synergistic (combining the drugs leads to a greater effect than expected (1+1=3), or antagonistic (combining the drugs leads to a smaller effect than expected (1+1=1). There is sometimes confusion about whether drugs are synergistic or additive, since the individual effects of each drug may vary from person to person. A synergistic interaction may be beneficial to individuals but may also increase the risk of overdose.
Some interactions should be avoided
It is important to note that additive and synergistic combinations are the riskiest combinations because they double or triple the effect of the stimulant or narcotic experience. A well-known dangerous combination is alcohol + GHB. Both drugs are narcotic (downers) and when combined, overdose can easily occur. Overdose caused by downers is life threatening because they reduce the ability to breathe and slow the heart rate.
The combination of several powerful stimulants such as methamphetamines, cocaine, and/or new drugs such as α-PVP can be very dangerous because the interaction has a very significant impact on your heart. Over time, you damage your heart and the risk of arterial disease increases rapidly.
Sildafenil (Viagra etc) has a safe interaction with most drugs used in chemsex. However, combining it with Poppers (amyl nitrite) can be dangerous because both drugs lower your blood pressure.
Check out the results for the most common chem combinations in our combination tool.