What volume of a 50 mg/3 mL solution equals 3 mg?

Medication Dosage Calculation

To obtain 3 mg from a solution of 50 mg in 3 mL, you need to withdraw 0.18 mL of the solution.

Step-by-Step Calculation Process

To solve this medication dosage calculation problem, we need to determine the concentration of the solution and then calculate the volume needed:

1. Determine the concentration of the solution:

   • Given information: 50 mg in 3 mL
   • Concentration = 50 mg ÷ 3 mL = 16.67 mg/mL 1

2. Calculate the volume needed for 3 mg:

   • Volume needed = Desired dose ÷ Concentration
   • Volume needed = 3 mg ÷ 16.67 mg/mL = 0.18 mL 1

Verification Method

You can verify this calculation using the ratio-proportion method:

• 50 mg : 3 mL :: 3 mg : x mL
• x = (3 mg × 3 mL) ÷ 50 mg = 0.18 mL 1

Common Pitfalls in Medication Calculations

• Concentration confusion: Always express concentration as mass per unit volume (mg/mL) to avoid errors 2
• Unit conversion errors: Ensure all units are consistent before performing calculations 2
• Decimal point errors: Be particularly careful with decimal placement, as a misplaced decimal can result in a 10-fold or greater dosing error 3
• Time pressure: Rushing calculations increases error risk; take time to double-check your work 3

Best Practices for Medication Calculations

• Use a standardized approach: Follow the same calculation method consistently 3
• Double-check all calculations: Verify results using a different calculation method 2
• Use appropriate tools: Consider using calibrated syringes designed for precise small-volume measurements 3
• Document clearly: Record both the calculation and the volume to be administered 2

For this specific case, drawing up 0.18 mL from the 50 mg/3 mL solution will provide the required 3 mg dose.