Geriatric Drug Dosage Calculator
Calculate safe drug dosages for elderly patients considering age-related pharmacokinetic changes, organ function, and frailty.
Patient Information
years
mg/dL
Clinical Status
mg
Recommended Starting Dose
250 mg
"Start low, go slow" - 50% of adult dose
🔬Creatinine Clearance
48.9 mL/min
📊Overall Adjustment
65%
🧓Frailty Level
Low
⚠️Beers Risk
Moderate
Dosing Strategy
Starting Dose: 250 mg (50% of normal)
Adjusted Target: 325 mg
Maximum Recommended: 325 mg
Adjustment Factors
Renal Factor: 75%
Hepatic Factor: 100%
Age-Related Renal Decline: 65%
Geriatric Considerations
- Increased receptor sensitivity may require lower doses
- Decreased total body water alters volume of distribution
- Reduced albumin increases free drug fraction
- Monitor for adverse effects at lower doses
Clinical Warning
Review Beers Criteria for potentially inappropriate medications. Consider drug-drug interactions, especially with polypharmacy. Titrate slowly based on response.
Age-Related Pharmacokinetic Changes
| Parameter | Change with Aging | Clinical Implication |
|---|---|---|
| Renal Function | Decreases 1%/year after 40 | Reduce doses of renally cleared drugs |
| Hepatic Metabolism | Phase I decreased, Phase II maintained | Avoid prodrugs, reduce hepatic-cleared drugs |
| Body Composition | Increased fat, decreased water | Lipophilic drugs accumulate longer |
| Serum Albumin | Decreased | Increased free drug for protein-bound drugs |
| Receptor Sensitivity | Increased for many drug classes | Enhanced effects at lower doses |