Definition

The readministration of a suspected drug to a patient after an adverse event, with observation of whether the reaction recurs. Positive rechallenge strongly supports causality.

Example

A patient developed rash after taking Drug X, which resolved upon discontinuation. When Drug X was inadvertently restarted, the rash recurred. This positive rechallenge supports a causal relationship.

Regulatory source

ICH E2A, Naranjo Algorithm

Common mistakes

Confusing rechallenge with dechallenge. Rechallenge is restarting; dechallenge is stopping.

Inspector question

How do you capture and code rechallenge information? How does it influence your causality assessment?

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