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The Internet has changed the way we live, work and shop. The growth of the Internet has made it possible to compare prices and buy products without ever leaving home. But when it comes to buying medicine online, it is important to be very careful. Some websites sell medicine that may not be safe to use and could put your health at risk. First, it's important to carefully consider the source of information and then to discuss the information you find with your health care professional. These questions and answers can help you determine whether the health information you find on the Internet or receive by e-mail from a Web site is likely to be reliable. You have to talk with your doctor and have a physical exam before you get any new medicine for the first time. Use only medicine that has been prescribed by your doctor or another trusted professional. Make sure the site requires a prescription and has a pharmacist available for questions.
There are more opportunities today than ever before to learn about your health and to take better care of yourself. It is also more important than ever to know about the medicines you take. Reading the label every time you use a nonprescription or prescription drug and taking the time to learn about drug interactions may be critical to your health. You can reduce the risk of potentially harmful drug interactions and side effects with a little bit of knowledge and common sense. 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. Mixing two drugs together could make one of the drugs ineffective. The combination also could increase a drug's effect, and be harmful. The result might be mild symptoms such as nausea, stomach upset, or headache, or more serious symptoms such as a dramatic drop in blood pressure, irregular heart beat, or damage to the liver-the primary way that drugs pass through the human body. 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. It used to be that the only way to test for drug interactions was in people. Now drug companies can take five test tubes with the five major pathways for metabolism and put their drugs in to see whether it's metabolized by CYP450. This allows to generate a list of possible interactions based on their findings. 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." In addition to having a good grasp of drugs and their effects, doctors take medication histories, and they consult with other members of their team to guide them in making decisions about drug interactions. They also use concise drug summaries and resources on pharmacological principles. Health professionals also use computer systems with drug-interaction screening software, electronic prescribing, and other technology. Mark Langdorf, M.D., chair of the department of emergency medicine at the University of California, Irvine, says, "In a busy emergency room, you have to quickly find out what a patient is taking and how those drugs could interact with other treatments." Drug interactions with other drugs includes both prescription and over-the-counter medicines. Tricyclic antidepressants such as Elavil (amitriptyline) and Pamelor (nortriptyline) can interfere with blood pressure-lowering Catapres (clonidine). Taking the antibiotic Cipro (ciprofloxacin) with antacids lowers Cipro's effectiveness. Some antibiotics, such as rifampin, can lower the effectiveness of birth control pills. Sildenafil, the active ingredient in the erectile dysfunction drug Viagra, should not be taken with nitrates for heart treatment because of the potential for dangerously low blood pressure.
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