Intravenous to oral antibiotic switch (IVOS)

IV-oral switching criteria have been developed nationally, available here but essentially:

• Switching should be considered 'within 48 hours of initiation' and daily thereafter
• Patient is afebrile, EWS decreasing, WCC trending towards normal, CRP decreasing
• Patient can take PO meds and there is a suitable formulation available
• No particular reasons to continue IV such as deep-seated infection, infections that are usually treated with prolonged IV courses, critical infections with high mortality.

These are not as helpful as they might have been, and sometimes subjective, but it is a worthy aim to get people onto PO antibiotics as soon as appropriate and we wish to promote this strongly in our Trust.

Key messages:

• Please be mindful of the benefits of IV-PO switching and consider it every time you review a patient on IV antibiotics
• We almost certainly over-estimate the benefits of IV antibiotics over PO: you get a quicker peak after the first dose, you might get higher tissue levels and you don't need to worry about GI absorption kinetics, but for most infections particularly once under control PO administration is fine. 
• Antibiotics should be switched 'when appropriate', acknowledging that this is a nuanced decision that is probably not captured well in the national IVOS criteria. With due respect to those criteria we suggest not to get too hung up on parameters like WCC and CRP - the EWS and the underlying diagnosis are more important when making oral switching decisions.