Medication Side Effects (Adverse effect)

In medicine, an adverse effect is a harmful and undesired effect resulting from a medication or other intervention such as surgery. An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect, and may result from an unsuitable or incorrect dosage or procedure, which could be due to medical error. Adverse effects are sometimes referred to as "iatrogenic" because they are generated by a physician/treatment. Some adverse effects only occur only when starting, increasing or discontinuing a treatment. Using a drug or other medical intervention which is contraindicated may increase the risk of adverse effects. Adverse effects may cause medical complications of a disease or procedure and negatively affect its prognosis. They may also lead to non-compliance with a treatment regimen.

The harmful outcome is usually indicated by some result such as morbidity, mortality, alteration in body weight, levels of enzymes, loss of function, or as a pathological change detected at the microscopic, macroscopic or physiological level. It may also be indicated by symptoms reported by a patient. Adverse effects may cause a reversible or irreversible change, including an increase or decrease in the susceptibility of the individual to other chemicals, foods, or procedures, such as drug interactions.

In clinical trials, a distinction is made between adverse events (AEs) and serious adverse events (SAEs). Generally, any event which causes death, permanent damage, birth defects, or requires hospitalization is considered an SAE.  The results of these trials are often included in the labeling of the medication to provide information both for patients and the prescribing physicians.

Reporting systems

In many countries, adverse effects are required by law to be reported, researched in clinical trials and included into the patient information accompanying medical devices and drugs for sale to the public.

United Kingdom

The Yellow Card Scheme is a United Kingdom initiative run by the Medicines and Healthcare products Regulatory Agency (MHRA) and the Commission on Human Medicines (CHM) to gather information on adverse effects to medicines. This includes all licensed medicines, from medicines issued on prescription to medicines bought over the counter from a supermarket. The scheme also includes all herbal supplements and unlicensed medicines found in cosmetic treatments. Adverse drug reactions (ADRs) can be reported by a number of healthcare professionals including physicians, pharmacists and nurses, as well as patients. For further information see the Yellow Card Scheme website, or find copies of the Yellow Card in the appedices of a BNF. To read reports from the UK Yellow Card Scheme you can download here.

United States

In the United States several reporting systems have been built, such as the Vaccine Adverse Event Reporting System (VAERS), the Manufacturer and User Facility Device Experience Database (MAUDE) and the Special Nutritionals Adverse Event Monitoring System. MedWatch is the main reporting center, operated by the Food and Drug Administration.

Australia

In Australia, adverse effect reporting is administered by the Adverse Drug Reactions Advisory Committee (ADRAC), a subcommittee of the Australian Drug Evaluation Committee (ADEC). Reporting is voluntary, and ADRAC requests healthcare professionals to report all adverse reactions to its current drugs of interest, and serious adverse reactions to any drug. ADRAC publishes the Australian Adverse Drug Reactions Bulletin every two months.The Government's Quality Use of Medicines program is tasked with acting on this reporting to reduce and minimize the number of preventable adverse effects each year.