Medication Dosage Calculator
Calculate precise doses based on body weight
Understanding Weight-Based Dosage
In clinical settings, especially in pediatrics and critical care, medications are often prescribed based on the patient's body weight. This ensures that the therapeutic level of the drug is achieved without reaching toxic thresholds. The standard measurement is typically milligrams of medication per kilogram of body weight (mg/kg).
How to Use the Dose Calculator
To calculate the correct amount of liquid medication to administer, follow these steps:
- Step 1: Enter the patient's weight and select the correct unit (kg or lbs).
- Step 2: Enter the dosage ordered by the physician (e.g., 15 mg/kg).
- Step 3: Look at the medication bottle for the concentration. This is often written as "250mg / 5mL". Enter 250 in the first concentration box and 5 in the mL box.
- Step 4: Click calculate to see the total milligrams needed and the exact volume in milliliters (mL) to measure.
Common Dosage Examples
Example 1: Pediatric Acetaminophen
A child weighs 22 lbs (10 kg). The recommended dose is 15 mg/kg. The concentration is 160 mg per 5 mL.
Calculation: 10kg × 15mg = 150mg. Volume = (150mg / 160mg) × 5mL = 4.69 mL.
Example 2: Antibiotic Suspension
An adult weighing 80 kg is prescribed 5 mg/kg of a liquid antibiotic. The concentration is 500 mg per 10 mL.
Calculation: 80kg × 5mg = 400mg. Volume = (400mg / 500mg) × 10mL = 8 mL.
Why Concentration Matters
The "concentration" or "strength" is the amount of actual drug dissolved in a specific amount of liquid. Misreading the concentration is a common source of medication errors. Always ensure you are looking at the "mg per mL" ratio rather than the total amount of medication in the whole bottle.