In a clinical trial, if an episode cannot be explained by the pharmacological properties of drugs involved, what action should the investigator take?

When an episode occurs in a clinical trial that cannot be explained by the pharmacological properties of the drugs involved, it is essential for the investigator to report it as a serious adverse event (SAE). This action is crucial because it ensures that any unexpected and potentially harmful effects resulting from the trial interventions are documented and assessed properly.

By submitting an SAE report for both subjects, the investigator acknowledges that the episode may have implications for the safety and well-being of all trial participants. Reporting unexpected events is a key responsibility in clinical research to maintain participant safety, comply with regulatory requirements, and uphold the integrity of the study. It allows for thorough investigation and contributes to the broader understanding of the drug's safety profile, helping in mitigating risks in current and future studies.

In summary, the decision to report both subjects reflects a commitment to transparency and participant safety, adhering to good clinical practice standards.