Changing from IV to PO antibiotics is an important antimicrobial stewardship intervention. In this article factors to consider when transitioning from an IV antibiotic to a PO antibiotic are discussed and relevant resources are identified.
Authored by: Timothy P. Gauthier, Pharm.D., BCPS-AQ ID
[Last updated: 7 March 2018]
When antibiotics are initiated within a hospital setting it is common to begin with a drug regimen that is administered via the intravenous (IV) route. Over time as the patient improves there comes a point where it is safe to transition to an oral (PO) antibiotic. This is intervention of going from an intravenous product to an oral product is commonly referred to as changing from IV to PO.
Changing IV to PO for antibiotics is a simple yet important action for hospitalized patients. IV to PO programs are commonly driven by the pharmacy service and are endorsed by multiple organizations as good a measure for antibiotic stewardship.
The CDC lists IV to PO as one of the interventions to consider for improving antibiotic use in their Core Elements for Hospital Antibiotic Stewardship Programs document. The National Quality Forum’s National Quality Partners Playbook on Antibiotic Stewardship in Acute Care identifies IV to PO change as a patient-specific intervention for intermediate programs, which falls under their examples to support optimal antibiotic use.
As new healthcare practitioners enter the workforce, current providers engage in antibiotic stewardship, and institutions seek to adhere to good antimicrobial stewardship practices, changing from IV to PO antibiotics will continue to be an important topic.
To provide a free resource on the topic of IV to PO and to also attempt to promote discussion on this topic, the following has been composed. Here you will find important information on changing from IV to PO antibiotics. Suggested resources and readings are additionally provided.
Note: This article is not meant to be an all-inclusive list of considerations for changing from IV to PO antibiotics and factors not discussed here may prevent such a change.
Terminology for changing from IV to PO antibiotics
- Sequential therapy: changing to the oral version of the same compound.
- Example: Levofloxacin 500mg IV Q24H to levofloxacin 500mg PO Q24H.
- Switch therapy: changing to an oral drug that is a different compound and has the same potency.
- Example: Levofloxacin 500mg IV Q24H to ciprofloxacin 500mg PO Q12H.
- Step-down therapy: changing to an oral drug that is a different compound and has different frequency, dose, or spectrum of activity.
- Example: Ampicillin-sulbactam 1.5gm IV Q6H to amoxicillin-clavulanic acid 875mg/125mg PO Q12H.
- Oral bioavailability: the amount of drug that enters systemic circulation when that drug is consumed orally.
Potential advantages of changing from IV to PO antibiotics
- Expedite removal of intravenous catheter and reduce chances for central line-associated bloodstream infections
- Expedite hospital discharge (i.e., reduce length of stay)
- Reduce volume of fluid administered to patient (can be especially important for patients with congestive heart failure)
- Increase patient satisfaction and comfort
- Reduce IV-related mobility restrictions
- Remove possibility for phlebitis / thrombophlebitis
- Reduce workload on pharmacy and nursing
- Decreased costs
Potential disadvantages of changing from IV to PO antibiotics
- Reduce ability to monitor adherence
- Reduce ease of access for emergently administering medications or fluids
- Potential for less clinical efficacy, depending on the disease state
Ideal characteristics of an antibiotic employed by an IV to PO program
- Clinical data supports efficacy for given indication, including adequate penetration to the site of infection
- Excellent bioavailability
- Infrequent dosing schedule
- No significant food-drug or drug-drug absorption issues
- Few adverse events when taken orally
- Easy storage
- Easy to swallow pills (including oral solution formulation available and/or capacity to crush tablets and/or capacity open capsules so can be given via NG, PEG, or PEJ tube)
- Not on back-order
Factors to screen for prior to changing from IV to PO antibiotics
- Suspected infection type(s)
- Duration of IV antibiotics received to date
- Common to give 24-48 hours IV before switching to PO to allow for more clinical data to become available and for patient to show clinical improvement
- Clinical improvement
- Stabilized vital signs
- Heart rate < 90 beats per minute (i.e., not tachycardic)
- Respiratory rate < 20 breaths per minute (i.e., not tachypnic)
- Stable blood pressure and mean arterial pressure
- Improvement in fever curve
- Afebrile (T < 100.4 F) at least 24 hours
- Take note of antipyretic therapy usage
- Afebrile (T < 100.4 F) at least 24 hours
- Resolving leukocytosis
- Ideally WBC < 15 cells/mm3
- Symptomatic improvement
- Mental status improvement
- Stabilized vital signs
- Medication profile (taking note of potential for drug-drug interactions)
- Labs including renal function and hepatic function
- Ability to swallow or receive enteral feeding
- Eating food and drinking fluids
- Tolerating other oral medications
- Receiving parenteral nutrition (e.g., PPN, TPN)
- Sensitivity profile of infecting organism(s)
- Supporting data for using oral antibiotics to treat the given infection type & organism
Factors that may prevent changing from IV to PO antibiotics
- Necessary medication(s) not available in an oral formulation
- Clinical instability
- Active order for no medications by mouth (NPO status)
- Ongoing nausea and/or vomiting
- Significant aspiration risk
- Abnormal gastrointestinal system anatomy (e.g., history of colectomy)
- Abnormal gastrointestinal transit time (e.g., severe diarrhea)
- Malabsorption syndrome
- Gastrointestinal obstruction (e.g., ileus)
- Active gastrointestinal bleed
- Continuous gastric suctioning
- Continuous tube feeds that cannot be interrupted
- Actively receiving high-dose vasopressors (can compromise gastrointestinal blood flow and reduce absorption)
- Oral antibiotics not favorable for antibiotic indication
- Potential examples: bloodstream infection, infective endocarditis, meningitis, brain abscess, acute osteomyelitis, necrotizing fasciitis, febrile neutropenia, endophthalmitis, or orbital cellulitis
- Lack of functioning immune system interfering with assessment of clinical improvement
- Microbiology cultures have not had enough time to incubate
Approximate oral bioavailability* of some antimicrobial drugs that may be considered for IV to PO conversion
Acyclovir (15%), Amoxicillin-clavulanic acid (30%), Azithromycin (40%), Cefixime (45%), Cefuroxime axetil (40%), Letermovir (35%), Penicillin V (25%)
Amoxicillin (75%), Ampicillin (50%), Cefpodoxime proxetil (50%), Delafloxacin (60%), Dicloxacillin (70%), Valacyclovir (55%), Valganciclovir (60%)
Ceftibuten (80%), Ciprofloxacin (80%), Clindamycin HCl (90%), Doxycycline (>90%), Fluconazole (>90%), Isavuconazonium sulfate (95%), Levofloxacin (100%), Linezolid (100%), Metronidazole (80%), Minocycline HCl (90%), Moxifloxacin (90%), Rifampin (90%), SMX-TMP (95%), Tedizolid (90%), Voriconazole (95%)
*May vary based upon renal function, patient age, drug-drug interactions, drug-food interactions, formulation, fasting versus with food, dosage, or other.
IV to PO Resources & Readings
Journal Articles & Guidance Documents
- CDC’s core elements of hospital antibiotic stewardship programs.
- Intravenous to Oral Therapy Conversion. Chapter 29 from the Competence Assessment Tools for Health-System Pharmacists Fourth Edition. 2008.
- Implementing a program for switching from i.v. to oral antimicrobial therapy. American Journal of Health-System Pharmacy. 2001.
- Antibiotic duration and timing of the switch from intravenous to oral route for bacterial infections in children: systematic review and guidelines. Lancet. 2016.
- Switch over from intravenous to oral therapy: a concise review. Journal of Pharmacology and Pharmacotherapeutics. 2014.
Quick References and Overviews
- Public Health Ontario IV to PO Overview
- SHEA Quick Guide for IV to PO Conversion
- Southern Health Quick Guide for IV to PO Switch
- Alberta Health Services IV to PO Quick Reference
- University of Rhode Island IV to PO Quick Reference
Institutional Policies and Procedures
- Jackson Memorial Hospital Antibiotic IV to PO Conversion Policy & Procedure
- Stanford Health Care IV to PO Policy & Procedure
- Northern Health IV to PO Conversion Clinical Practice Standard
- Nottingham University Hospitals Guideline for IV to PO Switch
- Gloucestershire Hospitals IV to PO switch Guideline
- Children’s Health Queensland Hospital and Health Service IV to PO Guideline
- New York-Presbyterian Community Acquired Pneumonia and IV to PO Guideline
I hope you have found this to be a helpful resource.
To close out this article, I would like to share a statement that an unknown person once said while debating when to change from an IV antibiotic to a PO antibiotic.
“The bug does not know how the drug got there.”
This statement may be helpful to share with others as you consider if it is time to change from an IV antibiotic to an oral antibiotic.
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