IV to oral switch (IVOS) procedure

Oral antibiotics, especially those with high oral bioavailability, can be used effectively to treat infections.

When to consider oral switch:

1. Is your patient improving?

Thing to consider:

patient clinically improving
NEWS2 stable or falling
infection markers (e.g. temperature, WCC) stable or falling.

2. Does your patient have an oral/enteral route?

Things to consider:

patient eating/drinking/NG in place
no GI issues (malabsorption/vomiting)
patient compliance with orals

3. Are there supportive infection diagnostic results?

Can oral regimes be guided by positive microbiology samples/other relevant diagnostics?

For some bug-drug combinations high dose oral regimes may be required.

4. Is there a complicated/deep-seated infection?

These infections are not necessarily a contraindication to oral regimes, indeed it’s becoming more common for oral regimes to be used. Please discuss with microbiology/infection specialist.

5. Can I make an empirical oral switch?

For common infections there are empirical oral switch antibiotics and empirical durations.

Common IVOS regimes can be found throughout our guidance and are summarised below:

Indication	Total duration (IV + oral^$)	Empiric Oral Switch
Indication	Total duration (IV + oral^$)	1st Line	2nd Line/ Penicillin allergy/ Previous MRSA
Sepsis of unknown source	5 days	Co-trimoxazole 960mg every 12 hours (IF intra-abdominal source likely ADD Metronidazole 400mg every 8 hours)	Co-trimoxazole 960mg every 12 hours (IF intra-abdominal source likely ADD Metronidazole 400mg every 8 hours)
Skin and Soft Tissue Infections
Cellulitis	5 days	Flucloxacillin 1g every 6 hours	Doxycycline 100mg every 12 hours OR Clarithromycin 500mg every 12 hours
Diabetic foot infection (mild)	7 days	Flucloxacillin 1g every 6 hours	Doxycycline 100mg every 12 hours OR Co-trimoxazole 960mg every 12 hours
Diabetic foot infection (moderate)	7 days	Flucloxacillin 1g every 6 hours AND Metronidazole 400mg every 8 hours	Co-trimoxazole every 12 hours AND Metronidazole 400mg every 8 hours
Human/Animal Bite Infection	5 days	Co-amoxiclav^* 625mg every 8 hours	Doxycycline 100mg every 12 hours AND Metronidazole 400mg every 8 hours
Respiratory Infections
Community Acquired Pneumonia (CURB 0-2)	5 days	Amoxicillin⁺ 500mg-1g every 8 hours	Doxycycline 200mg on first day then 100mg daily
Community Acquired Pneumonia (CURB 3-5)		Co-amoxiclav^*+ 625mg every 8 hours	Doxycycline 200mg on first day then 100mg daily
Aspiration Pneumonia (low severity)		Amoxicillin 1g every 8 hours	Co-trimoxazole 960mg every 12 hours OR Doxycycline 200mg on first day then 100mg daily
Aspiration Pneumonia (high severity)		Amoxicillin 1g every 8 hours AND Metronidazole 400mg every 8 hours	Co-trimoxazole 960mg every 12 hours AND Metronidazole 400mg every 8 hours OR Doxycycline 200mg on first day then 100mg daily AND Metronidazole 400mg every 8 hours
Hospital-acquired Pneumonia (late onset)		Doxycycline 200mg on first day then 100mg daily	Co-trimoxazole 960mg every 12 hours
Urinary tract Infections
Pyelonephritis/ Urosepsis/ Upper Urinary Tract Infection	7 days	Co-trimoxazole 960mg every 12 hours OR Co-amoxiclav^* 625mg every 8 hours	Co-trimoxazole 960mg every 12 hours
Intra-abdominal Infections
Biliary tract infection/ Appendicitis/ Diverticulitis	5 days (after adequate source control)	Co-trimoxazole 960mg every 12 hours AND Metronidazole 400mg every 8 hours OR Co-amoxiclav^* 625mg every 8 hours	Co-trimoxazole 960mg every 12 hours AND Metronidazole 400mg every 8 hours
Spontaneous bacterial peritonitis	5 days	Co-trimoxazole 960mg every 12 hours OR Co-amoxiclav* 625mg every 8 hours	Co-trimoxazole 960mg every 12 hours

^*Suitable for those ≤ 65 years old with a low risk of C.diff infection (CDI). See risk factors for CDI.

⁺ For CAP consider if atypical cover required (patient has risk factors or compatible clinical features), see atypical pneumonia.

Please remember to add stop dates for prescriptions e.g. in HEPMA.