contraindication
Meaning of contraindication: The mirror image of an indication: a specific reason in this particular person for not doing what would otherwise be the right thing.
Definition of contraindication
A contraindication is a circumstance that makes a particular treatment, drug or procedure inadvisable or unsafe, because in that situation the expected risks outweigh the expected benefit. It attaches to the combination of an intervention and a person rather than to the intervention alone. Contraindications are described as absolute, meaning the intervention is ruled out, or relative, meaning caution and a weighing of risks.
How do absolute and relative contraindications differ?
| Absolute | Relative | |
|---|---|---|
| What it means | The harm is expected to be serious enough that the intervention is not used | The risk is raised but may still be outweighed by the benefit |
| How it is handled | An alternative is sought | Risks and benefits are weighed for the individual situation |
| Example of the reasoning | A previous severe reaction to the same drug | A drug that is usually avoided in a particular condition but may be justified when nothing else will serve |
The line between the two is not always fixed, and the same factor can be absolute in a routine setting and relative in an emergency where the alternative is worse.
Where do contraindications come from?
Most are recorded in the approved product information for a medicine or the accepted description of a procedure, derived from the trials that supported approval and from harms reported afterward. Common sources include a documented allergy to the substance or a close relative of it, an interaction with another drug already being taken, an organ that cannot clear the drug, pregnancy or breastfeeding, and an underlying disease that the intervention would worsen. Contraindications also arise from equipment rather than from chemistry, as with metal implants and certain scanners.
How does it relate to an indication and to a side effect?
An indication is the reason to use an intervention: the condition it is approved and expected to help. A contraindication points the other way, naming who should not receive it. The two coexist without conflict, since the same drug can be indicated for a condition and contraindicated in a person who happens to have that condition alongside something else. A side effect is different again: it is an unwanted effect that can occur when the intervention is used, not a reason established in advance for withholding it. A serious side effect experienced once, though, frequently becomes a contraindication to any further exposure.
Used in a sentence
A severe prior allergic reaction may be a contraindication to receiving the same drug.
Good to know
A relative contraindication calls for the risks and benefits to be weighed in the individual case, whereas an absolute contraindication generally rules the intervention out.
Word origin
Where “contraindication” comes from
From Latin contra, meaning against, and indicare, meaning to point out or indicate, so the word names something pointing against an intervention that would otherwise be indicated.