Level of Significance: Stop-Light Rating System Occurrence/Severity
  Likely Probable Possible Unlikely
High        
Moderate        
Mild        
Insignificant        
 

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 = Clinical research indicates that this interaction is likely to occur in most patients.

Probable = Clinical research or pharmacokinetic studies in humans suggests that this interaction will occur in a significant portion of patients.

Possible = Clinical research, pharmacokinetic data in humans or animals, or in vitro research suggest that this might occur in some patients.

Unlikely = Clinical research, pharmacokinetic data in humans or animals, or in vitro research suggest that this interaction can occur, but is not likely to occur in many patients.

 

Severity
High = Life threatening or severe impairment possible

Moderate = Moderate impairment or significant discomfort possible

Mild = Mild impairment or mild discomfort possible

Insignificant = Drug levels may be affected, but a clinically significant interaction is not likely.