Anytime you take more than one medication, or even mix it with certain foods, beverages, or over-the-counter medicines, you are at risk of a drug interaction. Most drug interactions are not serious, but because a few are, it is important to understand the possible outcome before you take your medications.
Drug-drug interactions - These are the most common type of drug interaction. The more medications you take, the greater the chance for your drug interacting with another medicine. Drug-drug interactions can decrease how well your medications work, may increase minor or serious unexpected side effects, or even increase the blood level and possible toxicity of a certain drug. For example, if you take a pain medication, like Vicodin, and a sedating antihistamine, such as Benadryl, at the same time you will have an additive amount of drowsiness as both medications cause this side effect.
Drug-food/beverage interactions - You have probably seen the stickers on your prescription bottle to “avoid grapefruit juice” at one time or another. This may seem odd, but certain medications can interact with foods or beverages. For example, grapefruit juice can lower the levels of enzymes in your liver responsible for breaking down medications. Blood levels of an interacting drug may rise, leading to toxicity. This interaction can occur with the commonly used statins to lower cholesterol, like atorvastatin, lovastatin, or simvastatin. The result can be muscle pain, or even severe muscle injury known as rhabdomyolysis.
Drug-disease interactions - Drug interactions don’t always occur with just other drugs or foods. Your existing medical condition can affect the way a drug works, too. For example, over-the-counter oral decongestants like pseudoephedrine (Sudafed) or phenylephrine (Sudafed PE) may increase blood pressure and can be dangerous if you have have high blood pressure.
Interaction checker URl:http://www.webmd.com/interaction-checker/