From the Guidelines
The medication infusion formula is: Infusion rate (mL/h) = (Dose ordered × Patient weight × 60 minutes) ÷ (Concentration × Time in minutes). This formula allows healthcare providers to calculate the correct rate at which to administer intravenous medications. For example, if a patient needs dopamine at 5 mcg/kg/min, weighs 70 kg, and the concentration is 400 mg in 250 mL, you would calculate: (5 mcg/kg/min × 70 kg × 60 min) ÷ (400,000 mcg ÷ 250 mL) = 13.1 mL/hr.
Key Considerations
- For weight-based medications, always verify the patient's current weight and double-check your calculations 1.
- For critical medications like vasopressors, insulin, or heparin, use a smart pump with appropriate guardrails when available.
- This formula works because it converts the ordered dose into the total amount needed per hour, then adjusts for the concentration of the medication in the solution.
- Remember that different medications may require different units of measurement, so always confirm units and convert as needed before calculating.
Medication Specifics
- Dopamine: 2-20 mg/kg/min, preparation can be calculated using the ‘‘rule of 6’’ or by preparing a standard drug concentration and calculating the individual dose 1.
- Epinephrine: 0.1 mg/kg/min, preparation can be calculated using the ‘‘rule of 6’’ or by preparing a standard drug concentration and calculating the individual dose 1.
Administration
- Always monitor patients for signs of volume overload, especially those with underlying congestive heart failure or chronic renal disease 1.
- Use large volumes of normal saline or colloid solution as needed, but monitor patients closely for signs of volume overload 1.
From the FDA Drug Label
DOSAGE & ADMINISTRATION ... Dopamine Hydrochloride in 5% Dextrose Injection should be infused into a large vein whenever possible ... The less concentrated 800 mcg/mL solution may be preferred when fluid expansion is not a problem The more concentrated 1600 mcg/mL or 3200 mcg/mL solutions, may be preferred in patients with fluid retention or when a slower rate of infusion is desired. Rate of Administration: ... Each patient must be individually titrated to the desired hemodynamic or renal response to dopamine. Suggested Regimen: ... Begin infusion of dopamine hydrochloride solution at doses of 2 to 5 mcg/kg/min in adult or pediatric patients who are likely to respond to modest increments of heart force and renal perfusion In more seriously ill patients, begin infusion of dopamine hydrochloride at doses of 5 mcg/kg/min and increase gradually, using 5 to 10 mcg/kg/min increments, up to a rate of 20 to 50 mcg/kg/min as needed.
The formula for medication infusion is not explicitly stated, but the dosage rates are provided as:
- 2 to 5 mcg/kg/min for adult or pediatric patients
- 5 mcg/kg/min with gradual increases of 5 to 10 mcg/kg/min up to 20 to 50 mcg/kg/min for more seriously ill patients The concentration of the solution can be:
- 800 mcg/mL
- 1600 mcg/mL
- 3200 mcg/mL 2
From the Research
Medication Infusion Formula
The formula for medication infusion is not explicitly stated in the provided studies. However, the studies provide information on the dosages and administration of various medications, including:
- Dopamine: 2.5.0, and 10.0 microgram/kg/min 3
- Norepinephrine: 0.02,0.05, and 0.10 microgram/kg/min 3
- Dobutamine: 2.5.0, and 10.0 microgram/kg/min 3
Key Considerations
When administering medications, especially vasopressors, it is crucial to consider the individual patient's response and adjust the dosage accordingly. The studies highlight the importance of:
- Monitoring hemodynamic parameters, such as heart rate, mean arterial pressure, and cardiac index 3, 4, 5
- Adjusting medication dosages based on patient response and clinical endpoints 6, 3
- Considering the potential risks and benefits of different medications, such as the use of norepinephrine plus vasopressin in patients with sepsis and heart failure 4
Administration Guidelines
While the studies do not provide a specific formula for medication infusion, they do offer guidance on administration protocols, including: