Side effects are unwanted effects of a medicine. All medicines can cause side effects. It’s important to know the side effects of your medicines so that you know what to do if you get them.
What are medicine side effects?
Any unwanted or unexpected effects of a medicine are called side effects. They are also sometimes called adverse effects or adverse reactions. Side effects can also occur with interactions with other medicines or food.
Not all side effects are serious. Most are mild, although some medicines have serious side effects.
You can often avoid side effects by taking the medicine exactly according to the instructions, for example after eating food, or at a certain time of the day.
Some side effects may get better over time. For example, a new medicine might cause nausea at first but then this will go away. Sometimes side effects don’t happen right away but develop after taking the medicine for a while.
What types of medicines can cause side effects?
All types of medicines can have side effects. This includes prescription medicines and over-the-counter medicines that you can buy from a pharmacy, supermarket or other shops. Vitamins and minerals can also have side effects, as can any herbal, complementary, alternative or natural medicine.
Even though all medicines can cause side effects, not everyone will get them.
How to get help if you have side effects
If you think you might be having a serious side effect, see your doctor or hospital immediately. If it’s an emergency, call triple zero (000).
If you think you have taken too much of a medicine, call the Poisons Information Centre, 24 hours a day on 13 11 26.If it’s not an emergency but the side effects are bothering you, talk to your doctor or pharmacist. You can also call healthdirect on 1800 022 222 (known as NURSE-ON-CALL in Victoria) to speak to a registered nurse.
Where to get information on side effects
For information about potential side effects, speak to your doctor or pharmacist.
Here are some questions you might want ask.
- What are the possible side effects of the medicine?
- How commonly do the side effects happen?
- Does the medicine have any serious side effects, and what’s the risk?
- What can I do to avoid or reduce the risk of side effects?
- Do the side effects get better with time?
- What should I do if I think I’m having a side effect?
You can also get information on side effects from the medicine’s Consumer Medicine Information (CMI) leaflet, which is available from your pharmacist for all prescription and some non-prescription medicines. You can also search for CMIs in healthdirect's medicines section.
Thinking about side effects
If you are thinking about starting a new medicine, it is worth thinking about the side effects. How common are they? How serious are they? And what do they mean to you?
This is especially important if you have a serious health condition and the medicines might have serious side effects.
Looking for more medicine information?
healthdirect’s medicines section allows you to search for medicines by brand name or active ingredient. It provides useful information about medicines such as their use, whether they are available on the Pharmaceutical Benefits Scheme and product recalls.
Learn more here about the development and quality assurance of healthdirect content.
Last reviewed: April 2020