Module 6: how drugs work: learner's workbook

8.4 Drug interactions

Page last updated: 2004

Drug interaction occurs when a drug acts on the body along with another drug. This interaction can change the effect of one or both drugs on the body. When two drugs of a similar type interact, the overall effect of one or both of the drugs can increase. Mixing drugs (often referred to as poly-drug use), can therefore be a very risky activity.

Some drug interactions can be very dangerous - especially when any combination of the following drugs are taken together:

  • alcohol
  • heroin
  • benzodiazapines
It is interesting to note that many heroin users who have died of drug overdoses had also consumed alcohol and/or prescription drugs in addition to heroin.

Drugs can act together so that the overall effect is far greater than the two added together. Their effect can be multiplied. This is called potentiation.

Question - What is the relevance of knowing about drug interactions for workers?

Answer - (Write your answer, then check the possible answers page.)


Some of the key issues in pharmacology include:
  • intoxication
  • tolerance
  • dependence (both physical and psychological)
  • drug interaction
  • potentiation.