Adverse effect

An adverse effect is an undesired harmful 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. If it results from an unsuitable or incorrect dosage or procedure, this is called a medical error and not a complication. Adverse effects are sometimes referred to as 'iatrogenic' because they are generated by a physician/treatment. Some adverse effects occur only when starting, increasing or discontinuing a treatment. An adverse effect is an undesired harmful 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. If it results from an unsuitable or incorrect dosage or procedure, this is called a medical error and not a complication. Adverse effects are sometimes referred to as 'iatrogenic' because they are generated by a physician/treatment. Some adverse effects 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 complications of a disease or procedure and negatively affect its prognosis. They may also lead to non-compliance with a treatment regimen. Adverse effects of medical treatment resulted in 142,000 deaths in 2013 up from 94,000 deaths in 1990 globally. 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 terms of drugs, adverse events may be defined as: “Any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product and which does not necessarily have to have a causal relationship with this treatment.” In clinical trials, a distinction is made between an adverse event and a serious adverse event. Generally, any event which causes death, permanent damage, birth defects, or requires hospitalization is considered a serious adverse event. The results of trials are often included in the labelling of the medication to provide information both for patients and the prescribing physicians. The term 'life-threatening' in the context of a serious adverse event refers to an event in which the patient was at risk of death at the time of the event; it does not refer to an event which hypothetically might have caused death if it were more severe. 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. Investigators in human clinical trials are obligated to report these events in clinical study reports. Research suggests that these events are often inadequately reported in publicly available reports. Because of the lack of these data and uncertainty about methods for synthesising them, individuals conducting systematic reviews and meta-analyses of therapeutic interventions often unknowingly overemphasise health benefit. To balance the overemphasis on benefit, scholars have called for more complete reporting of harm from clinical trials. 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 health care professionals including physicians, pharmacists and nurses, as well as patients. 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.