|
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. 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. 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.
Drug interactions may make your drug less effective, cause unexpected side effects, or increase the action of a particular drug. Some drug interactions can even be harmful to you. 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. 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. 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. This phase of research in test tubes, known as in vitro studies, allows researchers to perform drug-interaction studies in labs by testing a drug with other drugs that have the same route. This has made the research faster and more accurate. If two drugs go through the same enzyme, the presence of one drug can prevent the metabolism of the other. So this allows you to look at the worst-case scenarios and ask: 'What if we put this drug with that one, knowing that they have the same route?'" Not everything that happens in a test tube will become meaningful in humans, though. Results from these test-tube studies can tell us whether need to do further testing in people to find out if an interaction is clinically significant. Researchers say there are several important variables that affect individual differences in how drugs are metabolized, including race, gender, age, and health conditions. For example, people with kidney or liver disease don't eliminate drugs from their system as well as people who are healthy. Very young children and older people have slower drug metabolism than others, and women may metabolize drugs differently than men in some cases. 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. But it is good way -- consumers remind doctors of everything they take when they are prescribed a new medication. So a patient might say: "Now remember, I'm also taking birth control pills. Is there a risk of interaction with this new medicine?" 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.
|
