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Calculate how medications are eliminated from your body over time using half-life decay
| Medication | Half-Life | 5 Half-Lives | Category |
|---|---|---|---|
| Ibuprofen | 2 hours | 10 hours | Pain/Anti-inflammatory |
| Acetaminophen | 2-3 hours | 10-15 hours | Pain/Fever |
| Metformin | 6 hours | 30 hours | Diabetes |
| Lisinopril | 12 hours | 2.5 days | Blood Pressure |
| Sertraline | 26 hours | 5.4 days | Antidepressant |
| Fluoxetine | 4-6 days | 20-30 days | Antidepressant |
| Diazepam | 20-100 hours | 4-21 days | Benzodiazepine |
| Warfarin | 20-60 hours | 4-12 days | Anticoagulant |
Half-life is the time required for the concentration of a drug in the body to decrease by 50%. It determines how long a drug remains active and how frequently it needs to be taken.
Half-life helps determine dosing schedules, predict drug interactions, plan for surgery or procedures, and understand how long side effects may last. It is also crucial for drug testing and withdrawal management.
A drug is considered essentially eliminated after 5 half-lives (about 97% gone). However, highly sensitive tests may still detect trace amounts. Fat-soluble drugs may be stored in tissues and released slowly over time.
No. Metabolism varies based on genetics, age, liver function, kidney function, other medications, and lifestyle factors like smoking. Some people are genetically fast or slow metabolizers of certain drugs.
Some drugs are converted to active metabolites that also have therapeutic effects and their own half-lives. For example, fluoxetine's metabolite norfluoxetine has an even longer half-life than the parent drug.
Generally, you cannot significantly speed up elimination. Staying hydrated and physical activity may marginally help. Some drugs have specific antidotes or can be removed by dialysis in emergencies. Never try to rapidly eliminate medications without medical supervision.
This calculator provides general estimates based on average half-life values. Individual metabolism varies significantly. Do not adjust medications without consulting your healthcare provider. Always follow prescribed dosing instructions.
Most drugs follow first-order kinetics, where a constant fraction is eliminated per unit time. This produces the predictable half-life pattern used in this calculator.
Some drugs (like alcohol at high levels) follow zero-order kinetics, where a constant amount is eliminated per hour regardless of concentration. This calculator does not apply to those drugs.
Some drugs distribute into different body compartments at different rates, resulting in multiple half-lives. This calculator uses a simplified single-compartment model.