Lithium Dosing For Adults   

Marshall Pierce, Pharm.D.

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Use the tab key to navigate the form. Required data entry fields are teal in color. Other fields are output only. 
Enter Age (years)
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 lithium. When more than one factor is present the values are multiplied to obtain a final result. If you wish to be conservative when multiple drug interactions are present select the drug with the greatest impact.
Other significant interactions:
Decease clearance: Low salt diet, volume depletion, hypothyroidism (untreated); Increase clearance: caffeine 300 mg increase clearance 26% for 4 hours, theophylline, sodium loading. 

Concurrent hydrochlorthiazide (clearance decreased 50%)
Concurrent Indomethacin, 150 mg per day or greater (clearance decrease 30%)
Concurrent angiotensin converting enzyme inhibitor (clearance decrease 50%)
Select Dosage Form
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 Daily Dose (mg)
For average level of 0.8 mEq/Liter based on Dosing Weight
Enter Rounded Dose (mg)
Select Dosage Interval
Calculated Peak (mEq/Liter)   
Calculated Trough (mEq/Liter) 
Calculated Average level (mEq/Liter)       

Calculated Level 12 hours post-dose (mEq/Liter)
Chronic Therapy 
  Lithium 0.6-0.8 mEq /Liter 
Acute Mania 
  Lithium 0.8-1.2 mEq/Liter 

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 will be used to calculated the patient's elimination rate constant (K).
Enter Actual Measured Steady State Level mEq/liter.  Levels should be drawn 12 hours after the evening dose, as this is how therapeutic levels were defined during clinical studies.  Serum levels are recommended after 5 half-lives.
Enter Time Level Drawn FROM START OF PREVIOUS DOSE (hours)
K (hours-1) Fit (Fit from level, time of level,  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.