Multivitamin/Multimineral

• What’s on the label may not be what’s in the product. For example, the FDA has found prescription drugs, including anticoagulants (e.g., warfarin), anticonvulsants (e.g., phenytoin), and others, in products being sold as dietary supplements. You can see a list of some of those products on the FDA’s Tainted Supplements webpage.     
• A 2012 Government study of 127 dietary supplements marketed for weight loss or to support the immune system found that 20 percent made illegal claims.     
• Some dietary supplements may harm you if you have a particular medical condition or risk factor or are taking certain prescription or over-the-counter medications. For example, the herbal supplement St. John’s wort makes many medications less effective.     
• Dietary supplements result in an estimated 23,000 emergency room visits every year in the United States, according to a 2015 study. Many of the patients are young adults having heart problems from weight-loss or energy products and older adults having swallowing problems from taking large vitamin pills.     
• Although it’s still rare, more cases are being reported of acute (sudden) liver damage in people taking dietary supplements in the United States and elsewhere. The liver injury can be severe, can require an emergency liver transplant, and is sometimes fatal.     
• Many dietary supplements (and some prescription drugs) come from natural sources, but “natural” does not always mean “safe.” For example, the kava plant is a member of the pepper family but taking kava supplements can cause liver disease.     
• A manufacturer’s use of the term “standardized” (or “verified” or “certified”) does not necessarily guarantee product quality or consistency.  

• If you’re going to have surgery, be aware that certain dietary supplements may increase the risk of bleeding or affect your response to anesthesia. Talk to your health care providers as far in advance of the operation as possible and tell them about all dietary supplements that you're taking.    
• If you’re pregnant, nursing a baby, trying to get pregnant, or considering giving a child a dietary supplement, consider that many dietary supplements have not been tested in pregnant women, nursing mothers, or children.    
• If you’re taking a dietary supplement, follow the instructions on the label. If you have side effects, stop taking the supplement and contact your health care provider. You may also want to contact the supplement manufacturer.  

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. 

Contraindications and drug interactions have not been identified by www.drugs.com. Merely type in the the vitamin or mineral name within their "checker" bar and follow the links to provide data and information.

This collection of fact sheets and other resources from the NIH Office of Dietary Supplements and other federal government sources presents information about dietary supplements and their ingredients. These include vitamins, minerals, herbs and botanicals, probiotics, and more. Many of these resources are available in versions written for consumers (in both English and Spanish) and also for health professionals.

Multivitamins/multiminerals (MVMs) are the most frequently used dietary  supplements, with close to half of American adults taking them. MVMs  cannot take the place of eating a variety of foods that are important to  a healthy diet. Foods provide more than vitamins and minerals. Many  foods also have fiber and other substances that can provide health  benefits. However, some people who don’t get enough vitamins and  minerals from food alone, or who have certain medical conditions, might  benefit from taking one or more of these nutrients found in  single-nutrient supplements or in MVMs. However, evidence to support  their use for overall health or disease prevention in the general  population remains limited.