Stop-light Rating System

Level of Significance: Occurrence/Severity

MAJOR = Do not use combination; contraindicated; strongly discourage patients from using this combination; a serious adverse outcome could occur.

MODERATE = Use cautiously or avoid combination; warn patients that a significant interaction or adverse outcome could occur.

MINOR = Be aware that there is a chance of an interaction; advise patients to watch for warning signs of a potential interaction.

Likelihood of Occurrence

LIKELY = Well-controlled human studies have demonstrated existence of this interaction.

PROBABLE = Interaction has not been documented in well-controlled studies, however interaction has been demonstrated in human studies or in controlled animal studies plus multiple case reports.

POSSIBLE = Interaction has been documented in animal or in vitro research, or interaction has been documented in humans but is limited to case reports or conflicting clinical research.

UNLIKELY = Interaction has been demonstrated in animal or in vitro research but has been shown not to occur in humans.

Severity

HIGH = Life threatening or requires medical intervention to prevent a serious adverse event.

MODERATE = Worsened clinical status and/or requires medication adjustment.

MILD = May cause minor clinical side effects. Unlikely to require medication adjustment.

INSIGNIFICANT = Drug or supplement levels may be affected but will not cause clinical effects.

Level of Evidence