NHS Greater Glasgow & Clyde Area Drug and Therapeutics Committee
Greater Glasgow and Clyde Medicines
Medicines Update

The BNF/BNFC interaction sections are changing

What’s new?
The interactions section in the BNF and BNF for Children (BNFC) is changing. Print copies of BNF 74 and BNFC 2017-18 have the new format and digital versions (Medicines Complete and the new BNF App) will be updated in the coming months. The content is more consistently structured and gives more information about the severity of an interaction, to aid clinical decision making.
The previous use of the black dot has been removed. Scroll down to find out more…

How do I access the new interactions information?
Accessing information in the print product will be different. Notes that were previously in the BNF main text are either included in Appendix 1 or signposted from Appendix 1 so you only have one place from which to start your search for interactions information. Appendix 1 will also contain easy to use tables that bring together drugs that have pharmacodynamic effects of particular clinical significance, such as those that prolong the QT interval. Dose adjustments due to interactions will remain in the drug monograph, consistent with digital outputs.

What are the main features and benefits?

  • Finding interactions should be quicker and simpler
  • The biggest change is acknowledgment that predictions behind interactions are now much more reliable. Predicted interactions, where the result is substantiated by the known effects of the drugs and likely to result in a clinically important effect, are now more thoroughly covered.
  • Levels of evidence and severity of an interaction is now included. This helps distinguish between interactions that may result in highly detrimental effects and interactions that may cause minimal inconvenience to a patient.
  • A number of previously listed interactions have been removed, usually because there is no evidence or the effect is a known and often intended use of drugs together.

What are the levels of severity?
The black dot only allowed for two levels of severity to be represented. In the new content, there are four levels of severity and these are now expressed by use of words not symbols.

  • SEVERE – the result may be a life-threatening event or have a permanent detrimental effect.
  • MODERATE – the result could cause considerable distress or partially incapacitate a patient; they are unlikely to be life-threatening or result in long-term effects.
  • MILD – the result is unlikely to cause concern or incapacitate the majority of patients.
  • UNKNOWN – used for those interactions that are predicted, but there is insufficient evidence to hazard a guess at the outcome.

What are the levels of evidence?
These terms are present to indicate the evidence base on which the interactions information rests.

  • STUDY – for interactions where the information is based on a formal study including those for other drugs with the same mechanism (e.g. known inducers, inhibitors, or substrates of cytochrome P450 isoenzymes or P-glycoprotein).
  • ANECDOTAL – interactions based on either a single case report or a limited number of case reports.
  • THEORETICAL – interactions that are predicted based on sound theoretical considerations. The information may have been derived from in vitro studies or based on the way other members in the same class act.

Where can I find further information?
You can access more information at BNF.org/newbnfinteractions or download the FAQs here.


Published 25/10/17