adverse reaction
Unwanted medical outcome
An adverse reaction is an unintended harmful response to something, especially a medication, vaccine, or medical treatment.
The term appears frequently in healthcare contexts: She had an adverse reaction to the anesthesia.
It can extend to negative responses more broadly—to foods, chemicals, or environmental factors.
- side effectUnintended secondary outcome
- drug interactionSubstances altering each other's effects
- allergyAdverse immune response
- allergic responseImmune system's mistaken attack
- rashHeedless or skin irritation
severe allergy · hives · nausea · stomach upset · swelling · anaphylaxis · epi pen · medication · drug · warning · symptoms · intolerance · sensitivity · inflammation · itching · vomiting · dizziness · complication
- Medical Eventssurgery, diagnosis, treatment, procedure, operation
- medical issuesdiagnosis, symptoms, complications, prognosis, treatment failure
- Cosmetic Safetypatch test, allergy warning, expiration date, shelf life, preservatives
- drug effectsanalgesia, stimulation, vasodilation, vasoconstriction, nausea
- drug reactionsside effects, drug allergy, anaphylaxis, hypersensitivity, toxicity
- Medical Harmsmedication errors, surgical error, surgical errors, wrong medication, misdiagnosis
adverse reactiontherapeutic effect
Health improvement from treatment
recovery · remission · efficacy · improvement · tolerance
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