Theophylline Dosing For Adults & Children to 1 Year of Age   

Use the tab key to navigate the form. Required data entry fields are teal in color. Other fields are output only. 
Enter Age (years) down to 1 year of age.
Enter Height in
Enter Actual Weight in
Select Sex  
Enter Most Recent Serum Creatinine (mg/dl)
Enter Previous Serum Creatinine (mg/dl)
Use the same value twice if renal function is stable.

Enter time between serum creatinines (hours). Use 24 if renal function is stable. Creatinines should be > 1 T1/2 apart to accurately determine creatinine clearance when renal function is changing.

The factors below are known to clinically impact the kinetics of theophylline. When more than one factor is present the values in decimal format are multiplied to obtain a final result. If you wish to be conservative when multiple drug interactions are present select one factor that is present that increases clearance the most and one factor that is present which decreases clearance the most.
Other significant interactions:
Decease clearance:
Increase clearance:

Smoking History (clearance increased 60%)
CHF (clearance decrease 60%)
Cystic Fibrosis (clearance increase 50%)
Acute Pulmonary Edema (clearance decreased 50%)
Acute Viral Illness (clearance decrease 50%)
Hepatic Cirrhosis (clearance increase 50%)
Severe Obstructive Pulmonary Disease (clearance decrease 20%)
Cimetidine (clearance decrease 40%)
Ciprofloxacin (clearance decrease 30%)
Erythromycin (clearance decrease 25%)
Influenza Vaccine (clearance decreased 50%)
Phenobarbital (clearance increase 30%)
Phenytoin (clearance increase 60%)
Propranolol (clearance decrease 40%)
Rifampin (clearance increase 30%)
Select Fraction of Administered Dose that is active ingredient (Theophylline) 
Aminophylline=0.84,  Aminodur =0.84, Choledyl=0.64, Theophylline & Others= 1

 

Select Dosage Form (bioavailability=1)
Select Drug
   
Calculated Lean Body Weight (kg)
Calculated Drug Dosing Weight (kg)
Calculated Creatinine Clearance (ml/min)
Calculated T1/2 for CREATININE (hours)
Calculated Drug K (hours-1)
Calculated Drug T1/2 (hours)
Calculated Drug Vd (liters)
Calculated Drug Clearance (liters/hour)
Calculated Loading Dose (mg)
For  level of 10 mcg/ml based on Dosing Weight assuming no drug on board
Calculated Total Daily Dose (mg)
For average level of 10 mcg/ml based on Dosing Weight
Calculated Hourly Dose (mg)
For average level of 10 mcg/ml based on Dosing Weight
Enter Rounded Dose (mg)
Select Dosage Interval
 
The brochodilator effect of theophylline is proportional to the logarithm of the serum concentration over the range 5-20 mcg/ml.

Calculated Peak (mcg/ml)
  Maximum Peak 20 mcg/ml 

Calculated Trough (mcq/ml)
  Usual Goal 5-15 mcg/ml   

Calculated Average level (mcg/ml)    
Serum level analysis: Please complete the input boxes below if you have an actual level and the time is was drawn. These values along with the entered dosage history and dosage form will be used to calculated the patient's elimination rate constant (K) and clearance.
Enter Actual Measured Steady State Level mcq/ml. 
Troughs are recommended. For unevenly spaced dosing intervals, levels are assumed to be drawn before the first dose of the day.  For continuous infusions levels can be drawn anytime once steady steady is acheived. 
Serum levels are recommended daily for critically ill  hospitalized patients and after 3-5 half-lives of starting therapy or dosage adjustment for others.
Enter the time in hours that the level was drawn after the PREVIOUS DOSE.  For unevenly spaced dosing intervals levels are assumed to be drawn before the first dose of the day. Use any time except for 0 for continuous infusions.
 
K (hours-1) Fit (Fit using level, time of level,  dosage form, and entered dosage history.)
Thanks for using the program. If you have any comments, suggestions or questions please contact the author.

Copyright Marshall A. Pierce PharmD, all rights reserved, no warranties expressed or implied.