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DISCLAIMER: The information contained herein should NOT be used as a substitute for the advice of an appropriately qualified and licensed physician or other health care provider. The information provided here is for informational purposes only. This tool may not cover all possible drug interactions. Please check with a physician if you have health questions or concerns. Although we attempt to provide accurate and up-to-date information, no guarantee is made to that effect.

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WebMD Interaction Checker - How It Works

Q: What is an interaction?

A: When certain medicines are taken together, an unintended reaction may occur. This is called an interaction. For example, one medicine may cause side effects that create problems with other medicines. Or one medicine may make another medicine stronger or weaker.

Q: How many medications can I enter?

A: You can enter up to 30 medications however the results returned reflect only interactions between pairs of drugs and do not reflect interactions or incompatibilities arising from combinations of more than two drugs at a time. Therefore, if you enter more than two drugs the checker will compare each drug to every other drug one pair at a time but it will not evaluate the combination of all of the drugs together.

Q: What should I do if I think my medications show interactions?

A: Call your doctor or pharmacist if you are concerned about an interaction. Do not stop taking any prescribed medication without your doctor’s approval. Sometimes the risk of not taking the medication outweighs the risk of the interaction. The effect you are experiencing may not be caused by your drugs interacting, or by your medication. Your doctor and/or pharmacist can help find what the problem is.

Q: Why can’t I enter my medication?

A: There may be interactions for medications, especially nonprescription drugs or supplements that we do not have interaction information about. If we do not have interaction information for a certain medication we do not allow you to enter it.

Q: Can I enter prescription medication, over the counter (OTC), vitamins and supplements?

A: Yes, we have prescription medication, OTC, vitamins and supplements. If we do not have interaction data on a drug or vitamin you will not be able to enter it in the interaction checker.

Q: Does the interaction checker tell me my medication interacts with food?

A: This interaction checker DOES NOT include food/drug interactions. However – we may have an interaction for particular foods (for example grapefruit) or the ingredients in food. For example, we do not include coffee in our database but we can tell you if a medication interacts with caffeine.

Q: Why is my interaction listed multiple times?

A: In some cases two medications have multiple effects. The interaction checker will list both effects as a separate interaction. Also the way that drug A affects drug B may be different than how drug B affects drug A. We will list them both as separate interactions.

Q: How do you classify the seriousness of an interaction?

A: The following classification is used:

Contraindicated: Never use this combination of drugs because of high risk for dangerous interaction

Serious: Potential for serious interaction; regular monitoring by your doctor required or alternate medication may be needed

Significant: Potential for significant interaction (monitoring by your doctor is likely required)

Mild: Interaction is unlikely, minor, or nonsignificant