Dopamine Practice

Pharmacology: Dopamine Dosage Calculation

Case Study 1: Dopamine Administration

  • Order Details:

    • Dosage: 4 mcg/kg/min

    • Concentration: 400 mg Dopamine in 250 mL D5W

    • Patient Weight: 154 lbs

Calculation Steps:

  1. Convert Weight to kg:

    • Patient weight in kg = ( \frac{154 \text{ lbs}}{2.2} \approx 70 \text{ kg} )

  2. Calculate Total Dopamine Required:

    • Total dosage required in mcg = (4 mcg/kg/min) x (70 kg) = 280 mcg/min

  3. Convert mcg to mg:

    • Total dosage required in mg = ( \frac{280}{1000} = 0.28 \text{ mg/min} )

  4. Determine Concentration in mg/mL:

    • Concentration of Dopamine in solution = ( \frac{400 \text{ mg}}{250 \text{ mL}} = 1.6 \text{ mg/mL} )

  5. Calculate mL per min Needed:

    • mL/min = ( \frac{0.28 \text{ mg/min}}{1.6 \text{ mg/mL}} \approx 0.175 \text{ mL/min} )

  6. Convert to mL/hr:

    • mL/hr = 0.175 mL/min x 60 min/hr = 10.5 mL/hr

    • Rounded Value: 10 mL/hr

Case Study 2: Dopamine Administration

  • Order Details:

    • Dosage: 2 mcg/kg/min

    • Concentration: 200 mg Dopamine in 250 mL D5W

    • Patient Weight: 175 lbs

Calculation Steps:

  1. Convert Weight to kg:

    • Patient weight in kg = ( \frac{175 \text{ lbs}}{2.2} \approx 79.545 \text{ kg} )

  2. Calculate Total Dopamine Required:

    • Total dosage required in mcg = (2 mcg/kg/min) x (79.545 kg) ( \approx 159.09 \text{ mcg/min} )

  3. Convert mcg to mg:

    • Total dosage required in mg = ( \frac{159.09}{1000} \approx 0.159 \text{ mg/min} )

  4. Determine Concentration in mg/mL:

    • Concentration of Dopamine in solution = ( \frac{200 \text{ mg}}{250 \text{ mL}} = 0.8 \text{ mg/mL} )

  5. Calculate mL per min Needed:

    • mL/min = ( \frac{0.159 \text{ mg/min}}{0.8 \text{ mg/mL}} \approx 0.19875 \text{ mL/min} )

  6. Convert to mL/hr:

    • mL/hr = 0.19875 mL/min x 60 min/hr ( \approx 11.925 \text{ mL/hr} )

    • Rounded Value: 12 mL/hr

Case Study 3: Dopamine Administration

  • Order Details:

    • Dosage: 15 mcg/kg/min

    • Concentration: 400 mg Dopamine in 250 mL D5W

    • Patient Weight: 253 lbs

Calculation Steps:

  1. Convert Weight to kg:

    • Patient weight in kg = ( \frac{253 \text{ lbs}}{2.2} \approx 114.09 \text{ kg} )

  2. Calculate Total Dopamine Required:

    • Total dosage required in mcg = (15 mcg/kg/min) x (114.09 kg) ( \approx 1711.35 \text{ mcg/min} )

  3. Convert mcg to mg:

    • Total dosage required in mg = ( \frac{1711.35}{1000} \approx 1.71135 \text{ mg/min} )

  4. Determine Concentration in mg/mL:

    • Concentration of Dopamine in solution = ( \frac{400 \text{ mg}}{250 \text{ mL}} = 1.6 \text{ mg/mL} )

  5. Calculate mL per min Needed:

    • mL/min = ( \frac{1.71135 \text{ mg/min}}{1.6 \text{ mg/mL}} \approx 1.07084 \text{ mL/min} )

  6. Convert to mL/hr:

    • mL/hr = 1.07084 mL/min x 60 min/hr ( \approx 64.25 \text{ mL/hr} )

    • Rounded Value: 65 mL/hr

Summary of Calculated Infusion Rates:

  • Patient 1 (154 lbs): 10 mL/hr

  • Patient 2 (175 lbs): 12 mL/hr

  • Patient 3 (253 lbs): 65 mL/hr