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Millions of consumers are using the Internet to get health information. And thousands of web sites are offering health information. Some of those sites are reliable and up-to-date; some are not. How can you tell the good from the bad? Some websites that sell medicine can be not state-licensed pharmacies or aren't pharmacies at all; or may give a diagnosis that is not correct and sell medicine that is not right for you or your condition; or won't protect your personal information. Be sure your privacy is protected: look for privacy and security policies that are easy-to-find and easy-to-understand. Don't give any personal information such as social security number, credit card, or medical or health history, unless you are sure the website will keep your information safe and private.
If you take several different medicines, see more than one doctor, or have certain health conditions, you and your doctors need to be aware of all the medicines you take. Doing so will help you to avoid potential problems such as drug interactions. Early in a drug's development, companies conduct research to detect or predict potential interactions between drugs. Experts evaluate the drug-interaction studies as part of assessing a drug's safety. When a drug is taken orally, it usually travels from the stomach to the liver, where it can be metabolized-the process of breaking down and removing chemicals from the body. Enzymes are complex proteins that act as catalysts in starting or speeding up chemical reactions. They cause a specific chemical change in other substances without being changed themselves. The most important enzymes in the liver that metabolize drugs are called the cytochrome P450 family of enzymes. These enzymes break down drugs when they pass through the liver or small intestine. A drug may affect these enzymes by inhibiting them, which causes reduced activity of the enzyme and a buildup of the drug in the body. Or drugs may "induce" the enzymes, which causes increased activity of the enzyme and a reduction of the drug in the body. Three phases of clinical trials in humans must happen before a drug can be marketed. Phase 1 studies focus on a drug's side effects and how the drug is metabolized and eliminated from the body. Phase 2 studies focus on a drug's effectiveness. And Phase 3 studies gather more information on safety and effectiveness, which includes using the drug in combination with other drugs. Over the last several years, there has been a substantial increase in the number of drug-interaction studies the FDA sees in new drug applications. If drug interactions are significant enough, they can prevent a drug from being approved by the FDA. If the agency determines that known drug interactions can be managed and that a drug's benefits outweigh the risks for the intended population, a drug will be approved. Drug-interaction information then goes into the drug's labeling in the sections on "clinical pharmacology," "precautions," "warnings," "contraindications," and "dosage and administration." Drug interactions with dietary supplements includes herbs and vitamins, which can interact with drug-metabolizing enzymes. St. John's wort is an herb commonly used by people with cancer to improve mood, but research has shown it interferes with the metabolism of irinotecan, a standard chemotherapy treatment. Vitamin K (in dietary supplements or food) produces blood-clotting substances that may reduce the effectiveness of blood-thinning medicines like warfarin. Drug interactions with food and beverages, for example, taking quinolone antibiotics such as ciprofloxacin with food and drinks such as colas, coffee, and chocolate that contain caffeine may cause excitability and nervousness. There can be a potentially fatal increase in blood pressure if food containing tyramine is eaten when taking monoamine oxidase inhibitors, drugs that treat mood disorders. Examples of food with tyramine are cheese and soy sauce. Grapefruit juice should not be taken with certain blood pressure-lowering drugs or cyclosporine for the prevention of organ transplant rejection. Alcohol should not be taken with pain relievers such as Tylenol (acetaminophen) or ibuprofen because of the increased risk of liver damage or stomach bleeding.
Although medicines can make you feel better and help you get well, it's important to know that all medicines, both prescription and over-the-counter, have risks as well as benefits. The benefits of medicines are the helpful effects you get when you use them, such as lowering blood pressure, curing infection or relieving pain. The risks of medicines are the chances that something unwanted or unexpected could happen to you when you use them. Risks could be less serious things, such as an upset stomach, or more serious things, such as liver damage. The same is true before using any medicine. Every choice to take a medicine involves thinking through the helpful effects as well as the possible unwanted effects. In many situations, the expert advice of your doctor, pharmacist, or other health care professionals can help you make the decision. Important things is tell to your doctor about any allergies or sensitivities that you may have. Tell about anything that could affect your ability to take medicines, such as difficulty swallowing or remembering to take them. Before use a medicine make sure you understand the directions; ask your doctor if you have questions or concerns. Always double check that you have the right medicine. Read and follow the directions on the label and the directions from your doctor, pharmacist, or other health care professional. If you stop the medicine or want to use the medicine differently than directed, consult with your health care professional. Ask your doctor always if there are interactions with any other medicines or dietary supplements (including vitamins or herbal supplements), beverages, or foods. Use the same pharmacy for all of your medicine needs, whenever possible. Before starting any new medicine or dietary supplement (including vitamins or herbal supplements), ask your doctor again if there are possible interactions with what you are currently using.
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