How do you convert oral theophylline dose to intravenous aminophylline dose?

To convert the oral theophylline dose to intravenous aminophylline dose, understanding the bioavailability of the two medications is crucial. The bioavailability of oral theophylline is typically around 100%, meaning it is fully absorbed and utilized in the body when taken by mouth. However, when aminophylline is administered intravenously, it has a different pharmacokinetic profile.

When converting the doses, it's important to account for the fact that not all the theophylline is converted to active aminophylline at the same rate. The established conversion ratio is that the oral dose of theophylline is equivalent to approximately 0.8 times the intravenous dose of aminophylline. This ratio reflects how the two medications behave differently in the body and ensures that when transitioning from one form of administration to another, the therapeutic effect remains consistent.

Thus, when calculating the oral to intravenous dose conversion, multiplying the intravenous aminophylline dose by 0.8 allows for an accurate adjustment to maintain effective drug levels in the patient’s system. This is why this particular conversion factor is recognized as the correct approach in clinical settings.