There may be advantages in switching a patient who is receiving an intravenous medication to an oral formulation. This can be done if there is good evidence that the patient will benefit and not be adversely affected by the change.


Advantages of an intravenous regimen:

(1) It has more predictable kinetics, with the potential for higher serum levels.

(2) It does not require a functional gastrointestinal tract.

(3) It does not require patient participation.

(4) Noncompliance is not a problem.


Disadvantages to an intravenous regimen:

(1) IV formulations tend to be more expensive than the comparable oral formulation.

(2) Intravenous administration costs are more expensive than oral.

(3) Intravenous administration is more likely to have a complication (pain, infection, thrombosis, etc.)

(4) A person requiring an intravenous administration may have to return to the hospital for dosing or have a visit from a home health nurse.


Requirements for switching to oral dosing:

(1) An appropriate oral formulation is available.

(2) There are no contraindications.

(3) The gastrointestinal tract in functional.


Appropriate oral formulation:

(1) There is an oral formulation with a high oral bioavailability capable of delivering an adequate amount of drug.

(2) If a constant drug level is required, then a sustained-released formulation is available.

(3) A oral liquid formulation may be appropriate if the patient is unable to swallow solid tablets or capsules.

(4) The cost of oral therapy is less than that of parenteral administration.



(1) nausea and/or vomiting

(2) ileus or bowel obstruction

(3) severe diarrhea

(4) gastrointestinal disease, severe anasarca, bowel resection or bypass that interferes with drug absorption

(5) coma

(6) The drug is needed to treat a critical illness and the patient is not stable.


Evidence of a functional gastrointestinal tract:

(1) The patient is able to tolerates a significant oral intake (clear liquids, liquid diet or tube feedings with minimal residuals).

(2) The patient is taking other medications by mouth.


A patient on oral therapy can be monitored if there are questions of efficiacy:

(1) serum levels can be measured if there are questions about absorption or peak levels.

(2) clinical monitoring of response or deterioration


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