adverse reaction

Also found in: Acronyms.

ad·verse re·ac·tion

any undesirable or unwanted consequence of a preventive, diagnostic, or therapeutic procedure or regimen.
Farlex Partner Medical Dictionary © Farlex 2012

Adverse Effect

Malpractice An injury caused by medical management—rather than by the underlying disease—which prolongs hospitalization, produces a disability at the time of discharge, or both.
Aetiology Drug effects, wound infections, technical complications, negligence, diagnostic or therapeutic mishaps, and events occurring in A&E.
Therapeutics An undesirable and unintended, although not necessarily unexpected, result of therapy or other intervention—e.g., headache following spinal tap or intestinal bleeding associated with aspirin therapy.
Toxicology An abnormal or harmful effect on an organism due to exposure to a chemical or noxious substance. Adverse events cause functional or anatomic damage, irreversible changes in homeostasis, or increased susceptibility to other chemical or biologic stress.
Clinical findings Change in food or liquid consumption, body or organ weight, enzyme activity, visible illness or death. Nonadverse effects usually fade when the organism is distanced from the toxin.
Trial Any undesirable symptom, occurrence or effect which a trial subject experiences during the trial, which may or may not be related to the study agent or intervention.
Examples Unfavourable and unintended reactions or findings—e.g., abnormal lab results, symptoms, or disease temporally associated with the use of a medicinal (investigational) product, whether or not it actually is related to the product.

The term adverse effect is often used interchangeably with adverse reaction, which might be better reserved for clinical phenomena occurring during drug treatment when causality cannot be or is not ascertained.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

ad·verse re·ac·tion

(ad-vĕrs' rē-ak'shŭn)
Any undesirable or unwanted consequence of a preventive, diagnostic, or therapeutic procedure or regimen.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
Severe adverse reaction risk during mass treatment with ivermectin in loiasisendemic areas.
Serious Adverse Reaction (SAR): Multiple definitions are possible and no single one is correct in all situations.
"We have in place the Yellow Card Scheme which helps us identify previously unrecognised suspected adverse reactions."
This study suggests that patients with a history of a severe undiagnosed adverse reaction during anaesthesia should have appropriate investigation such as skin testing preoperatively, and that their elective surgery should be delayed if necessary, pending the outcomes of this investigation.
"This pushes us to think about precision care and about the role for regulation and legislation when it comes to labeling medications that contain an ingredient that may cause an adverse reaction."
* 2008--1 adverse reaction as a result of direct intervention by naturopath
The number of adverse reactions is divided by the number of traceable blood units and multiplied by 1.000 to have the incidence of adverse reaction per 1,000 blood units.
828 ERCPs were performed in high risk of CM adverse reaction patients including 127 ERCPs among patients with prior adverse reaction to iodine containing product and 701 in patients reporting any other allergic diathesis.
The incidence of adverse reactions in the two groups was 11.7% and 23.5% respectively, and the incidence of mouth dryness which is the major adverse reaction was 5.8% and 10.4% respectively (P<0.05), suggesting solifenacin was more safe and effective in relieving OAB.
VVR were the most common adverse reaction occurring in 67-95% of all donation-related reactions and in 1-5% of blood donors.
5.3 Cerebrovascular Adverse Reactions, Including Stroke in Elderly Patients with Dementia-Related Psychosis
In our MRI suite all information on contrast-enhanced studies, including the type and volume of the CM administered, the type and severity of any acute adverse reaction, and the need for any pharmacological treatment or resuscitation, is usually collected.