Frequently asked questions
What is a drug interaction?
A drug interaction is when one or more substances affect the way another drug works in the body. Interactions may alter wanted and unwanted effects, modify therapeutic potential, or change the level of toxicity.
When do drug interactions occur?
Drug interactions occur when two or more drugs are in the body at the same time. This may happen when they are taken together, hours apart, or sometimes even a day apart, depending on how long each substance remains active in the body.
How do drug interactions occur?
Drug interactions occur because drugs act on organs and biological systems in the body. When two or more substances affect the same organs or processes, their effects may combine, enhance, or oppose each other.
What effects can interactions have on medicinal drugs?
The effects of interactions on medicinal drugs depend on the substances involved. Interactions may modify the therapeutic effects of a medication or change the likelihood of unwanted effects or toxicity. We recommend consulting a healthcare professional when combining substances that include a medicinal drug.
What does Effect Level mean for an individual's experience and metabolism?
The way in which drugs alter an individual's experience and metabolism depends on three things: the drug, the individual and the setting. For the drug, the dose and route of administration play an important role. For the individual, the weight, age, sex, gender, tolerance, and health, among other factors, influence the outcome. For the setting, the location, social context, and time of day also affect the experience.
How to use the drug interactions tool?
This drug interactions checker helps you understand what to expect when combining drugs. To begin, select at least two drugs using 'Popular searches' or the search bar. You can select up to 8 drugs at a time, but the tool provides risks and descriptions in pairs. This means that if you select several drugs, the information shown refers to each possible pair of drugs rather than the whole combination at once. Below, you will find the predicted risk of harm associated with each drug pair. When you select an interaction, you can adjust the Effect Level ('low', 'medium', or 'high') and the route of administration. By default, we select Low Effect Level for both drugs and a route of administration for each drug. Adjust these factors to get a prediction more relevant to you.