What are interactions, and when are they most likely?
Interactions are when another medicine, food or drink (including alcohol) changes how a medicine works, or changes its side effects in some way. These interactions may be serious.
Interactions can be caused in many ways, but the most common are:
- by making your body absorb or get rid of a medicine slower or faster than usual; this can mean your usual dose is either too strong or not strong enough
- by adding together two or more medicines that when combined will give you too strong an effect, which can happen if you are taking two medicines that do similar things in your body.
Interactions are most likely to cause problems when you:
- start taking a medicine
- stop taking a medicine
- increase the dose of a medicine.
Ask your health professional if there are any likely interactions you should know about when you are starting a new medicine, and watch out for unexpected symptoms in the first few days after your medicines change in any way.
Looking for your medicine's side effects or interactions?
Use the Medicine Finder to search for your medicine to find out about its side effects and interactions, or ask your doctor or pharmacist.