This document provides information on dosing for three vasoactive medications: Norepinephrine, Dopamine, and Dobutamine. It gives the desired dose ranges for each medication in mcg/kg/min. It also provides information on the effects of low, medium, and high doses of Dopamine. The document outlines a single equation for calculating drip rates based on desired dose, patient weight, drug concentration, and time. It provides examples of using this equation to calculate initial and maximum drip rates for Norepinephrine and Dobutamine, as well as an initial drip rate for Dopamine. The document also shows how to calculate the dose if given the drip rate.
2. Desired dose (mcg/kg/min)
Norepinephrine:
0.2 to 2 mcg/kg/min
AHA: 0.01 to 3 ug/kg/min
Dopamine:
2 mcg/kg/min to max 20-50 mcg/kg/min
AHA: 2.0 to 20 mcg/kg/min
Dobutamine:
initial: 0.5 to 1 mcg/kg/min
maintenance: 2 to 20 mcg/kg/min
usual : 2-10 mcg/kg/min
AHA: 2.0 to 20 mcg/kg/min
3. Dopamine
Low dose: (1-5 mcg/kg/min) Increase urine output and renal blood flow
Medium dose: (5- 15 mcg/kg/min) Increase renal blood flow,cardiac output, heart
rate, and cardiac contractility
High dose: (20-50 mcg/kg/min) : Increase blood pressure and stimulate
vasoconstriction
4. YOU ONLY NEED ONE(1) EQUATION!
Drip rate = desired dose (mcg/kg/min) x body weight in kg x time (min/hr)
(ugtts/min or cc/hr) drug concentration( mg/ml) x 1000 mcg/mg
5. Example 1: Norepinephrine
A 55 yo female, diabetic , weighing 62 kg, has a 3 day history of body malaise,
fever, dysuria and flank pain. Few hours PTA, she had several episodes of vomiting
and generalized body weakness with decreased sensorium. At the ER, her VS were
BP 80/60, CR 110, RR 29, temp 39C, 94% O2 sat. After giving bolus of fluid at 30
cc/kg, and doing your ABCs, you intend to start Norepinephrine at 0.2
mcg/kg/min prepared as 8 mg of Norepinephrine in 250 cc D5W. What is the
initial drip rate? Maximum drip rate?
6. Solution:
Initial Drip rate: ( 0.2 mcg/kg/min)
cc/hr = (0.2 mcg/kg/min)x 62 kg x 60 min/hr
(8 mg/ 250 mL) x 1000 mcg/mg
= 23 cc/hr
Maximum Drip rate:
cc/hr = (2 mcg/kg/min)x 62 kg x 60 min/hr
(8 mg/ 250 mL) x 1000 mcg/mg
= 232 cc/hr
7. DOBUTAMINE
A 49 yo male, diabetic, hypertensive, weighting 54 kg, has 1 week history of easy
fatigability, 3 pillow orthopnea, PND, bipedal edema, and shortness of breath. Few
hours PTA, he had increased severity of dyspnea. At the ER, noted with neck vein
engorgement, diaphoresis, abdominal distention, bipedal edema and crackles all
over. BP was 90/60, HR 114, RR 32, T= 35.2 ,o2 sat 90%. You gave furosemide but
the BP went down to 80/50 mm Hg. After starting her on LD Norepinephrine, you
intend to give Dobutamine prepared as 250 mg in 250 mL d5W. What is the initial
drip rate if your desired dose is 2 mcg/kg/min?
NOTE: we don’t start Dobutamine alone when patient is hypotensive.
8. Solution:
Initial Drip rate: ( 5 mcg/kg/min)
cc/hr = (2 mcg/kg/min)x 54 kg x 60 min/hr
(250 mg/ 250 mL) x 1000 mcg/mg
= 6.48 cc/hr or 7 cc/hr
9. DOPAMINE
A 68 yo female, 57kg , came to the emergency room due to syncope. She had several
episodes of dizziness and syncope for the past 2 weeks but no consult was done. This
morning, she had another syncope hence family opted to bring her to the ER. She is
known hypertensive and diabetic with good compliance to maintenance medications.
Patient has unremarkable physical examination except for bradycardia at 43 beats/min.
On ECG she had sinus bradycardia with episodes of sinus pauses lasting less than 3
seconds. You diagnose her with Symptomatic Bradycardia, Sick sinus syndrome. BP
110/70, RR 20, 99% rm air. You gave her 3 doses of atropine 1.0 mg IV q 3 min and
Salbutamol nebulization but bradycardia was persistent so you plan to refer her to
Cardio for pacemaker insertion. However, while awaiting funds, you plan to start her on
Dopamine drip. You intend to give Dopamine starting at a dose of 2 mc/kg/dose
prepared as 200 mg in 250 mL D5W. What is the drip rate?
10. Solution:
Initial Drip rate: ( 2 mcg/kg/min)
cc/hr = (2 mcg/kg/min)x 57 kg x 60 min/hr
(200 mg/ 250 mL) x 1000 mcg/mg
= 8.55 cc/hr or 9 cc/hr
11. What is the dose of the drip if you are
given cc/hr?
Example: Patient X, weighing 58 kg is currently on Norepinephrine drip prepared
as 16 mg in 250 mL D5W running at 17 cc/hr. What is the dose of
Norepinephrine?
12. Solution: Just use simple math
17 cc/hr = X mcg/kg/min x 58 kg x 60 min/hr
(16 mg/ 250 mL) x 1000 mcg/mg
X = 1,088 / 3480 = 0.3 mcg/kg/min
