What Is Intravenous-to-Oral Switch Therapy?

There are three types of IV-to-PO therapies:

• Sequential therapy: Conversion from IV administration to oral medication using exactly the same compound and dosage.
• Switch therapy: Switching IV medication with oral equivalent using a different compound in the same class of drugs and potency.
• Step down therapy: Replacement of IV medication with an oral one which may be a different drug class, or within the same class but with a different dosage and frequency.

The benefits of IV-to-PO switch therapy include the following:

• Ease of administration.
• Reduced infection risk that can arise from the insertion of IV tube (cannula). A cannula remaining in the vein for several days can cause bacterial or fungal infections that require further treatment.
• Reduces risk of infection from endemic hospital pathogens such as Clostridium difficile.
• Reduced risk of inflammation in the vein and blood clot formation (thrombophlebitis) with early switch from IV to oral medication.
• Reduced costs because:
  • Oral drugs are less expensive than IV medications.
  • Needles, syringes and professional administration are not required.
  • Earlier discharge from hospital is possible.

IV-to-PO switch therapy can be used with many kinds of medications, but particularly useful in antibiotics. Many studies have shown that IV-to-PO switch therapy is a viable option in infectious diseases. Antibiotic IV-to-PO switch therapy has been effectively used in conditions such as:

• Community-acquired pneumonia (CAP): Pneumonia that is contracted from the general population outside the hospital. CAP is most commonly caused by Streptococcus pneumoniae, but also by a few other bacteria and viruses.
• Spontaneous bacterial peritonitis: Bacterial infection of the abdominal membrane (peritoneum) common with fluid collection (ascites) from liver cirrhosis.
• Pyelonephritis: Kidney inflammation from bacterial infection.
• Adult septic arthritis: Joint inflammation caused by bacterial infection.

Typically, intravenous antibiotics can be switched to oral medication in two or three days, provided the patient’s condition is stable. The important factors that influence switch to oral therapy include:

• Absence of suppurative (pus-forming) infection
• Ability for oral food intake
• No positive blood culture test results
• Respiratory rate
• Heart rate and blood pressure
• Absence of fever
• Oxygen saturation
• Patient’s mental status

To implement a safe and effective IV-to-PO switch therapy in community-acquired pneumonia, following criteria are essential:

• Improvement in cough and respiratory distress
• Absence of fever for at least eight hours
• White blood cell count within the normal range
• Ability for oral intake of food and medications

For successful implementation of IV-to-PO therapy, it is important for hospitals to establish a protocol to:

• Identify the patients on IV medication suitable for switch therapy
• Check if the patient’s condition is stable for switch therapy
• Implement the switch in consultation with the physician
• Monitor the patient’s progress after the IV-to-PO switch

A computerized program where the pharmacist, physician and infectious disease specialist coordinate the switch can streamline the process.