Unnecessary prolonged courses of Intravenous (IV) antimicrobials are associated with longer length of hospital stay, increased risk of morbidity and mortality related to IVline infections, as well as higher treatment cost1-3. Therefore, one of the core elements in antimicrobial stewardship (AMS) programme is to promote timely oral (PO) antimicrobials conversion (IVOC) once the patient is clinically stable, able to tolerate oral feeding and has no contraindications4-6.

Multiple studies have highlighted the benefits of IVOC, including decreased risk of healthcare-associated and cannula-related infections, reduced medical and hospitalisation costs, shorter hospital length-of-stay, with increased patient mobility and comfort2,3,5,7-10. Early IVOC also has been demonstrated to be safe and equally effective to prolonged IV antimicrobial courses with no negative impact on patient outcomes in terms of mortality, readmission or adverse drug reactions3, 9, 11.

IVOC should be considered within 48 to 72 hours of IV antimicrobial therapy5, 10, 12, 13. This period of time allows the clinician to evaluate patients’ microbiology results and assess their response to treatment. 

• Stable vital signs

-  Temperature >36°C and <38°C for 24 to 48 hours

-  Stable blood pressure (no unexplained hypotension)

-  No tachycardia (heart rate below 90 beats/min)

-  No tachypnoea (respiratory rate below 20 breaths/min)

• Stable immune response

 - White cell count between 4 and 12 x 109/L or normalising

 -  C-reactive protein reducing trend

• Gastrointestinal tract intact and functional

-  Oral fluids/food are tolerated (at least 1L/day of oral fluids or 40mL/hour of enteral nutrition)

-  No concerns about malabsorption

• Oral absorption is not compromised

-  No diarrhoea, vomiting, malabsorptive disorder, short bowel syndrome or swallowing disorder

• An appropriate oral antimicrobial is available, considering oral bioavailability, any clinically significant drug interactions or patient allergies

• No significant concerns over patient adherence to oral antimicrobial treatment

• Pneumonia

• Skin and soft tissue infections

•  Urinary tract infections

•  Intra-abdominal infections without deep-seated collection

• Uncomplicated Gram-negative bacteraemia

Early IVOC is not appropriate in infections which warrant prolonged course of IV antimicrobial or require very high tissue concentration which cannot be delivered via equivalent oral antimicrobial preparations such as5, 6, 10, 11:

• Bone and joint infections

• Central nervous system infections: meningitis, encephalitis, intracranial abscess

• Deep-seated abscess, abscess without incision or inadequately drained

• Endocarditis

• Exacerbation of cystic fibrosis or bronchiectasis

• Empyema

• High-risk neutropenia or severe infections during chemotherapy-related neutropenia

•  Infections of implants/prostheses/IV catheters

• Melioidosis (at least 14 days of IV therapy)

• Septicaemia or critical infection with high risk of mortality

• Severe soft tissue infections such as: necrotising fasciitis, Group A Streptococcal infections etc.

• Severely immunocompromised: solid organ transplant, bone marrow transplant

• Staphylococcus aureus bacteraemia 

• Treatment for liver abscesses, adequately drained abscesses and empyema, osteomyelitis and septic arthritis can be changed to oral therapy after ≥ 2 weeks of IV therapy 

References:

1. Barlow GD, Nathwani D. Sequential antibiotic therapy. Current Opinion in Infectious Diseases. 2000;13(6):599-607.

2. Cyriac JM, James E. Switch over from intravenous to oral therapy: A concise overview. J Pharmacol Pharmacother. 2014;5(2):83-7.

3. Garwan YM, Alsalloum MA, Thabit AK, Jose J, Eljaaly K. Effectiveness of antimicrobial stewardship interventions on early switch from intravenous-to-oral antimicrobials in hospitalized adults: A systematic review. Am J Infect Control. 2023;51(1):89-98.

4. Barlam TF, Cosgrove SE, Abbo LM, MacDougall C, Schuetz AN, Septimus EJ, et al. Implementing an Antibiotic Stewardship Program: Guidelines by the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America. Clin Infect Dis. 2016;62(10):e51-77.

5. Sevinç F, Prins JM, Koopmans RP, Langendijk PN, Bossuyt PM, Dankert J, et al. Early switch from intravenous to oral antibiotics: guidelines and implementation in a large teaching hospital. J Antimicrob Chemother. 1999;43(4):601-6.

6. MOH Malaysia. Protocol on Antimicrobial Stewardship (AMS) Programme in Healthcare Facilities. Second Edition ed. Petaling Jaya: Pharmaceutical Services Programme, Ministry of Health Malaysia; 2022.

7. Mouwen AMA, Dijkstra JA, Jong E, Buijtels P, Pasker-de Jong PCM, Nagtegaal JE. Early switching of antibiotic therapy from intravenous to oral using a combination of education, pocket-sized cards and switch advice: A practical intervention resulting in reduced length of hospital stay. Int J Antimicrob Agents. 2020;55(1):105769.

8. Schuts EC, Hulscher M, Mouton JW, Verduin CM, Stuart J, Overdiek H, et al. Current evidence on hospital antimicrobial stewardship objectives: a systematic review and meta-analysis. Lancet Infect Dis. 2016;16(7):847-56.

9. Nguyen AD, Mai-Phan T-A, Tran MH, Pham HT. The effect of early switching from intravenous to oral antibiotic therapy: A randomized controlled trial. J Pharm Pharmacogn Res. 2021;9:695-703.

10. Harvey EJ, McLeod M, De Brún C, Ashiru-Oredope D. Criteria to achieve safe antimicrobial intravenous-to-oral switch in hospitalised adult populations: a systematic rapid review. BMJ Open. 2023;13(7):e068299.

11. McCarthy K, Avent M. Oral or intravenous antibiotics? Aust Prescr. 2020;43(2):45-8.

12. Akhloufi H, Hulscher M, Melles DC, Prins JM, van der Sijs H, Verbon A. Development of operationalized intravenous to oral antibiotic switch criteria. J Antimicrob Chemother. 2017;72(2):543-6.

13. Harvey EJ, Hand K, Weston D, Ashiru-Oredope D. Development of National Antimicrobial Intravenous-to-Oral Switch Criteria and Decision Aid. J Clin Med. 2023;12(6).

14. The Sanford Guide to Antimicrobial Therapy app Sperryville, VA, USA: Antimicrobial Therapy Inc.; 2023.

15. Lexicomp. Version 7.7.4. ed: Wolters Kluwer: UpToDate Inc.; 2023.