IV to Oral Switch Therapy

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It is not necessary to treat every infection with parenteral antimicrobial agents. Even where initial therapy with parenteral agents is necessary it may be possible to switch to oral antimicrobial agents after 24 to 48 hours if the patient is responding well to treatment. Switching to oral therapy has advantages for the patient, staff and hospital.

Table 1: IV to Oral Switch Criteria

Table 1: IV to Oral Switch Criteria

In favour of switching

Reasons to avoid/delay switching

· Clinically improving

· Potential GI absorption problems

· Apyrexial for >24 hours

· Meningitis or CNS infection

· Oral fluids, food & medication tolerated

· Acute osteomyelitis/septic arthritis

· Suitable oral alternative

· Endocarditis

· No reason to avoid/delay switching

· Severe soft tissue infections

I f yes to all ‘In favour of switching’ without any ‘Reasons to avoid/delay switching’ consider switch to oral therapy.

· Staph aureus bacteraemia

· Inadequately drained abscess

· Neutropenic sepsis/septic shock

If in doubt discuss with Microbiology or Infectious Diseases or Pharmacy

Table 2: Antimicrobials with excellent bioavailability by the oral route

Table 2: Antimicrobials with excellent bioavailability by the oral route

Ciprofloxacin

Clarithromycin

Clindamycin (90%)

Co-trimoxazole

Fluconazole (90%)

Fusidic Acid/Sodium fusidate (91%)

Levofloxacin (99%)

Linezolid (100%)

Metronidazole (100%)

Posaconazole

Rifampicin

Voriconazole (96%)

Ref: The Sanford Guide to Antimicrobial Therapy Digital update Nov 2020

Table 3: Recommended Oral Agents when Switching from IV to Oral

Table 3: Recommended Oral Agents when Switching from IV to Oral

IV Antibiotic

Oral Option

Amoxicillin 500mg to 1g tds

Amoxicillin 500mg to 1g tds

Benzylpenicillin 1.2g to 2.4g qds

Amoxicillin 500mg to 1g tds OR Phenoxymethylpenicillin 666mg qds

Ceftriaxone

According to indication and culture & sensitivity. Discuss with Microbiology or Infectious Diseases

Cefuroxime 750mg to 1.5g tds + Metronidazole 500mg tds

There is no direct oral alternative; co-amoxiclav 625mg tds may be reasonable if NOT penicillin allergic, according to indication and culture & sensitivity. If penicillin allergic discuss with Microbiology or Infectious Diseases

Ciprofloxacin 400mg bd

Ciprofloxacin 500mg bd

Clarithromycin 500mg bd

Clarithromycin 500mg bd

Clindamycin 600mg to 1.2g qds

Clindamycin 300mg to 450mg qds

Co-amoxiclav 1.2g tds

Co-amoxiclav 625mg-1g tds

Co-trimoxazole

Co-trimoxazole same dose

Flucloxacillin 1g to 2g qds

Flucloxacillin 500mg to 1g qds

Fluconazole

Fluconazole same dose

Gentamicin dose per GAPP App calculator

According to indication and culture & sensitivity. Discuss with Microbiology or Infectious Diseases

Levofloxacin

Levofloxacin same dose

Linezolid

Linezolid same dose

Metronidazole 500mg tds

Metronidazole 400mg tds

Piperacillin/tazobactam

There is no direct oral alternative; but oral options may be available according to indication and culture & sensitivity; co-amoxiclav or co-amoxiclav plus ciprofloxacin may be options. Discuss with Microbiology or Infectious Diseases if necessary.

Rifampicin

Rifampicin same dose

Teicoplanin

There is no direct oral alternative but oral options may be available depending on indication and culture &  sensitivity data. Discuss with Microbiology or Infectious Diseases.

Vancomycin dose per GAPP App calculator

There is no direct oral alternative but oral options may be available depending on indication and culture & sensitivity data. Discuss with Microbiology or Infectious Diseases.