A man should never be ashamed to own he has been in the wrong, which is but saying... that he is wiser today than he was yesterday.

Alexander Pope, in Swift

Buying prescription medicine online

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.

The medicines that sold online can be fake (counterfeit or 'copycat' medicines); can be too strong or too weak, or have dangerous ingredients, or have expired (are out-of-date), or haven't been approved or checked for safety and effectiveness, can be made using non-safe standards, or not safe to use with other medicine or products you use.

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.

Buying your medicine online can be easy. Just make sure you do it safely.

It is possible to obtain the full benefits of medicines

For example, every time you get into a car, there are risks---the possibility that unwanted or unexpected things could happen. You could have an accident, causing costly damage to your car, or injury to yourself or a loved one. But there are also benefits to riding in a car: you can travel farther and faster than walking, bring home more groceries from the store, and travel in cold or wet weather in greater comfort.

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.

The benefit and risk decision is sometimes difficult to make. The best choice depends on your particular situation. You must decide what risks you can and will accept in order to get the benefits you want.

You have to always tell your doctor if you are or might become pregnant, or if you are nursing a baby. Always ask questions about any concerns or thoughts that you may have.

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.

Preventing serious drug interactions

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.

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.

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.

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.

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.

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."

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.

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.

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