Adverse side effects are any reactions to a medication or prescription drug that have negative implications. Some side effects to medication are unpleasant yet benign; for instance, allergy medications may cause drowsiness, or antibiotics may cause nausea, just to name a few. Adverse side effects, however, are generally severe enough to make the patient stop taking the medication, or could potentially cause damage over the long term.
Adverse side effects must be reported to a doctor immediately. Some are not discovered until a larger group of patients has taken the drug and experienced side effects; the manufacturer may then decide to pull the drug off the market entirely. For example, a drug may increase the risk of heart attack in patients, but this may not be discovered over the short term. Once this side effect is discovered, however, the drug will be pulled off the market for further study and a reformulation.
Sometimes, adverse side effects occur because the patient does not follow the directions when taking the drug. The patient may take too much, or may take it in conjunction with another drug. This is known as adverse drug interaction, and is the reason it is very important for the patient to tell his or her physician and pharmacist about every single medication that he is taking, whether it is another prescription drug or an over-the-counter drug. Other times, medical error, such as the mistake of a physician, can lead to adverse side effects.
Serious adverse effects are generally considered to be those that can cause permanent damage, birth defects, or death. Examples of these adverse side effects include kidney failure, liver damage, an increase in blood pressure or cholesterol that leads to heart disease, glaucoma, diabetes, seizures, birth defects, and depression or dementia, among many others. Some adverse effects may occur only when starting or stopping a treatment; for instance, nausea and diarrhea are common effects when starting antibiotics, but are generally not severe enough to require the patient to stop taking the drug, and will usually go away after a period of time.
Clinical drug trials are used to study new and existing drugs, and to determine if any adverse side effects exist. Results from the clinical trials are generally included in the information that is provided with the drug, once it has been approved for manufacture and for use in patients. It is important to read all this information carefully, follow the dosage instructions exactly, and to immediately notify the prescribing physician if any side effects occur.