Visualize medication accumulation and elimination with our interactive pharmacokinetic tool
Welcome to the Drug Loading & Withdrawal Calculator! This interactive drug dosage calculator online helps you visualize how medications accumulate in the body during repeated dosing and how they are eliminated after stopping. It uses core pharmacokinetic principles to simulate drug concentrations over time based on half-life, dose, and dosing interval.
This tool is designed as a reference for nurses, pharmacists, medical students, and clinicians performing drug calculations, complementing other tools such as a paracetamol calculator, ibuprofen dosage calculator, and narcotic calculator for safe medication management.
Choose from the dropdown list (half-life is preloaded for each drug)
Specify the amount in milligrams (mg) you're interested in
Specify hours between doses
Enter the duration of treatment in days
Click "Calculate & Plot" to see the loading (blue) and withdrawal (red) phases on the graph.
The graph displays key pharmacokinetic parameters to help you understand drug behavior:
Approximately 5 half-lives - when drug accumulation plateaus
Approximately 7 half-lives - when the drug is almost entirely cleared from the system
This allows students, healthcare professionals, and drug calculation nurses to understand the dynamics of drug accumulation and withdrawal in an intuitive, visual way.
This calculator is for educational and reference purposes only. It does not provide medical advice and should not be used to guide personal drug use or dosing decisions. Always consult a licensed healthcare professional before starting, adjusting, or stopping any medication.
The pharmacokinetic simulations are based on theoretical values such as half-life and elimination constants, which may vary significantly between individuals depending on factors such as age, body weight, kidney function, liver function, and other medications.
For precise dose adjustments (e.g. pediatric dosing, steroid calculators, vancomycin calculators, or paracetamol dosage calculators), always refer to local formularies (such as the BNF or FDA labeling) and professional guidance.
Visualize drug accumulation and elimination based on pharmacokinetics
Half-life:
Elimination Constant (k):
Accumulation Ratio:
Time to Steady State:
Time to Eliminate:
This calculator simulates drug accumulation during repeated dosing and elimination after stopping medication.
The graph shows drug concentration over time, with the loading phase (blue) and withdrawal phase (red).
