Question | Clinical relevance |
---|---|
Have you taken the medication before without adverse effects? | Prior drug exposure doesn’t entirely rule out an ADR, although tolerating treatment previously may make hypersusceptibility reactions less likely |
Did anything else change around the time of possible ADR other than the suspected drug (eg other treatments, over-the-counter medicines, disease progression) | Examination of whether there are alternative causes (other than the suspected drug) that could on their own have caused the reaction |
Did the reaction occur only after the drug was started? | While not all ADRs occur immediately or early in therapy (ie on drug challenge), an effect occurring before drug exposure is good counter evidence |
Did the reaction resolve when the drug was stopped (or when a specific treatment was given)? | Effects that disappear when treatment is stopped (de-challenge) may increase suspicion of an ADR unless an irreversible reaction |
Was there ever intentional or accidental use of the drug following an ADR? | An ADR occurring on re-exposure to a drug increases the probability of a causal relationship |
Based on original criteria described by Naranjo et al (1981).13