I. DOPAMINE
Generally used to augment BP and cardiac output in patients with cardiogenic shock
Dopamine releases norepinephrine from nerve terminals, which itself stimulates A1 and B1 receptors
Usually started at an infusion rate of 2-5 mcg/kg/min
Dose is increased every 2-5 minutes to a maximum of 20-50 mcg/kg/min A. Things to know about Dopamine:
Preparation One ampule contains 200 mg dopamine
Sample order Dopamine drip: 200mg dopamine (1 ampule) + 250 cc D5W to run for ____ cc/hr
Dopamine factor
For a formulation of 1 ampule (200mg) in 250 cc D5W factor, used is 13.3
For a formulation of 2 ampules (400mg) in 250 cc D5W factor, used is 26.6
NOTE: A more concentrated dose is usually chosen for patients who cannot tolerate fluid overload (e.g. patients with CHF, CKD)
B. Dopamine demonstrates varying Hemodynamic Effects based on the dose
DOSE MECHANISM OF ACTION EFFECT
< 2 mcg/kg/min Activates DA1 and DA2 receptors
Renal Vasodilation:
Vasodilation of splanchnic and renal vasculature
2-10 mcg/kg/min Activates B1-receptors
Inotropic:
Increase in cardiac output with little or no change in HR or SVR
> 10 mcg/kg/min
Effects on A1-receptors overwhelm the dopaminergic
receptors
Vasoconstrictor:
Vasoconstriction, leading to increase in SVR, LV filling pressures, and HR
Source: Fauci, et.al, Harrison’s Principles of Internal Medicine 19th edition, 2015.
C. Computation of Dopamine Drip Rate based on Desired Dose
mcg
Desired dose kg min x Body Weight (kg) Dopamine drip rate (ugtt/min) = Dopamine factor
D. Sample computation
55/F patient, 45kg, admitted for cardiogenic shock with BP of 80/50 mmHg
If our desired dose is 10mcg/kg/min (chronotropic/inotropic dose) and we decide to give 400mg (2 amps) dopamine (factor is 26.6), the dopamine rate is computed as follows:
mcg
Dopamine drip rate (ugtt/min) =
10 kg min x 45 (kg) =
16.9 = 17 cc/hr = 17 ugtt/min 26.6Sample chart order:
30
Start dopamine drip: 400mg (2amps dopamine) + 250cc D5W x 17 cc/hr (dose of ~10 mcg/kg/min)
Titrate by 2-3 cc/hr to maintain BP > 90/60
E. Reverse computation: computing for the DOSE of dopamine being administered
Note that when reporting/endorsing a case, it is better to state the dose of dopamine that the patient is being given and not the drip rate. To compute for the specific dose, use the following formula
Dopamine drip rate ugtt x Dopamine factor mcg min = min________________
Dopamine dose kg body weight (kg)
Example:
Patient is a 45-kg, 55/F, given 2 amps of Dopamine (200 mg/amp) in 250cc PNSS at a rate of 19 ugtts/min (or 19cc/hr). QUESTION: What is the dose of dopamine being given to the patient?
Dose given (in mcg/kg/min) = rate (in ugtt/min) x 26.6 = 19ugtt/min x 26.6 = 11.23mcg/kg.min 45 kg 45 kg
Answer: 11.23 mcg/kg/min is the dose being given to the patient at a rate of 19 ugtts/min (or 19cc/hr). Since we are giving 11.23 mcg/kg/min, we have a vasoconstricting effect which is beneficial in a patient with septic shock. If the patient is still hypotensive, we can increase the ugtt/min (titrate) up 34 ugtt/min (20mcg/kg/min) for a 45-kg patient (“dopa max”). If still with no response to maximal dopamine dosing, we can start another inotrope like norepinephrine.
In the computation, we used 26.6 because 2 ampules of dopamine were used for the patient.
F. For quick reference:
1. Dopamine 200 mg + 250 cc D5W preparation
Drip Rate (ugtt/min or
cc/hr)
Body Weight in Kg
40 kg 50 kg 60 kg 70 kg 80 kg 90 kg
Dose (mcg/
kg/min)
2.5 7.5 cc/hr 9.4 cc/hr 11.3 cc/hr 13.1 cc/hr 15.0 cc/hr 16.9 cc/hr 5.0 15.0 cc/hr 18.8 cc/hr 22.5 cc/hr 26.3 cc/hr 30.0 cc/hr 33.8 cc/hr 7.5 22.5 cc/hr 28.1 cc/hr 33.8 cc/hr 39.4 cc/hr 45.0 cc/hr 50.6 cc/hr 10.0 30.0 cc/hr 37.5 cc/hr 45.0 cc/hr 52.5 cc/hr 60.0 cc/hr 67.5 cc/hr 15.0 45.0 cc/hr 56.3 cc/hr 67.5 cc/hr 78.8 cc/hr 90.0 cc/hr 101.3 cc/hr 20.0 60.0 cc/hr 75.0 cc/hr 90.0 cc/hr 105.0 cc/hr 120.0 cc/hr 135.0 cc/hr 2. Dopamine 400 mg + 250 cc D5W Preparation
Drip Rate (ugtt/min or
cc/hr)
Body Weight in Kg
40 kg 50 kg 60 kg 70 kg 80 kg 90 kg
Dose (mcg/
kg/min)
2.5 3.8 cc/hr 4.7 cc/hr 5.6 cc/hr 6.6 cc/hr 7.5 cc/hr 8.4 cc/hr 5.0 7.5 cc/hr 9.4 cc/hr 11.3 cc/hr 13.1 cc/hr 15.0 cc/hr 16.9 cc/hr 7.5 11.3 cc/hr 14.1 cc/hr 16.9 cc/hr 19.7 cc/hr 22.5 cc/hr 25.3 cc/hr 10.0 15.0 cc/hr 18.8 cc/hr 22.5 cc/hr 26.3 cc/hr 30.0 cc/hr 33.8 cc/hr 15.0 22.5 cc/hr 28.1 cc/hr 33.8 cc/hr 39.4 cc/hr 45.0 cc/hr 50.6 cc/hr 20.0 30.0 cc/hr 37.5 cc/hr 45.0 cc/hr 52.5 cc/hr 60.0 cc/hr 67.5 cc/hr
31 II. DOBUTAMINE
A synthetic sympathomimetic amine with positive inotropic action
Effects are due to selective stimulation of B1 adrenergic receptors
A. Things to know about Dobutamine:
Preparation One ampule contains 250 mg dobutamine
Sample order Dobutamine drip: 250mg dobutamine (1 amp) + 250 cc D5W to run for ___ cc/hr
Dobutamine factor
For a formulation of 1 ampule (250 mg) in 250 cc D5W, factor used is 16.6
For a formulation of 2 ampules (500 mg) in 250 cc D5W,factor used is 33.2
NOTE: A more complicated dose is usually chosen for patients who cannot tolerate fluid overload (e.g. patients with CHF, CKD)
B. Effects of Dobutamine (dose-dependent)
Minimal positive chronotropic activity at low doses(2.5 mcg/kg/min) and moderate chronotropic activity at higher doses
Usually given at 10 mcg/kg/min, however, its vasodilatory effect at this dose precludes its use in patients with decreased systemic vascular resistance
C. Computation of Dobutamine Drip Rate based on Desired Dose
Desired dose mcg min x Body weight (kg) Dobutamine Drip Rate (ugtt/min) = kg_____________________
Dobutamine factor
D. Sample computation
60/M patient, 50 kg, in cardiogenic shock from decompensated heart failure with BP of 80/50 mmHg
If our desired dose is 5 mcg/kg/min and we decide to use 500 mg (2 amps) dobutamine (factor is 33.2) 5 mcg min x 50 (kg)
Dobutamine Drip Rate (ugtt/min) = kg_______________ = 7.5 = 8cc/hr = 8 ugtt/min 33.2
Sample chart order:
Start dobutamine drip: 500 mg (2 amps dobutamine) + 250 cc D5W x 8 cc/hr (dose of 5 mcg/kg/min)
Titrate by 2-3 cc/hr to maintain BP >90/60 until 15 cc/hr (~10 mcg/kg/min)
The maximum dose of 15 cc/hr was computed using the dose 10 mcg/kg/min
Note that when endorsing a case, it is better to state the dose of dobutamine that the patient is being given and not the drip rate
To compute for the specific dose, use the following formula
Dobutamine drip rate ugtt x Dobutamine factor Dobutamine Dose mcg min = min_____________________
kg body weight (kg)
32 E. For quick reference:
1. Dobutamine 250 mg + 250 cc D5W Preparation Drip Rate
(ugtt/min or cc/hr)
Body Weight in Kg
40 kg 50 kg 60 kg 70 kg 80 kg 90 kg
Dose (mcg/
kg/min)
2.5 6.0 cc/hr 7.5 cc/hr 9.0 cc/hr 10.5 cc/hr 12.0 cc/hr 13.5 cc/hr 5.0 12.0 cc/hr 15.0 cc/hr 18.0 cc/hr 21.0 cc/hr 24.0 cc/hr 27.0 cc/hr 7.5 18.0 cc/hr 22.5 cc/hr 27.0 cc/hr 31.5 cc/hr 36.0 cc/hr 40.5 cc/hr 10.0 24.0 cc/hr 30.0 cc/hr 36.0 cc/hr 42.0 cc/hr 48.0 cc/hr 54.0 cc/hr 15.0 36.0 cc/hr 45.0 cc/hr 54.0 cc/hr 63.0 cc/hr 72.0 cc/hr 81.0 cc/hr 20.0 48.0 cc/hr 60.0 cc/hr 72.0 cc/hr 84.0 cc/hr 96.0 cc/hr 108.0 cc/hr 2. Dobutamine 500 mg + 250 cc D5W Preparation
Drip Rate (ugtt/min or
cc/hr)
Body Weight in Kg
40 kg 50 kg 60 kg 70 kg 80 kg 90 kg
Dose (mcg/
kg/min)
2.5 3.0 cc/hr 3.8 cc/hr 4.5 cc/hr 5.3 cc/hr 6.0 cc/hr 6.8 cc/hr 5.0 6.0 cc/hr 7.5 cc/hr 9.0 cc/hr 10.5 cc/hr 12.0 cc/hr 13.5 cc/hr 7.5 9.0 cc/hr 11.3 cc/hr 13.5 cc/hr 15.8 cc/hr 18.0 cc/hr 20.3 cc/hr 10.0 12.0 cc/hr 15.0 cc/hr 18.0 cc/hr 21.0 cc/hr 24.0 cc/hr 27.0 cc/hr 15.0 18.0 cc/hr 22.5 cc/hr 27.0 cc/hr 31.5 cc/hr 36.0 cc/hr 40.5 cc/hr 20.0 24.0 cc/hr 30.0 cc/hr 36.0 cc/hr 42.0 cc/hr 48.0 cc/hr 54.0 cc/hr
III. NORADRENALINE/NOREPINEPHRINE
A potent vasoconstrictor and inotropic stimulant
Despite non-significant improvement in survival compared to patients given dopamine, the relatively safer profile of norepinephrine makes it a good initial vasopressor therapy
Usually started at a dose of 2 to 4 mcg/minand titrated upward as necessary
If systematic perfusion or systolic pressure cannot be maintained at >90 mmHg with a dose of 15 mcg/min, it is unlikely that a further increase in dose will be beneficial
A. METHOD 1: Long Method Step 1: Compute for concentration
stock (mg) x 1000 mcg Concentration = 250 cc IVF 1 mg
EXAMPLE: For 4 mg norepinephrine + 250 cc D5W
4 mg x 1000 mcg Concentration = 250 cc 1 mg
Step 2: Compute for infusion rate
mcg / min
Infusion rate cc = dose kg x weight (kg) x 60 min/hr hr concentration (mcg/cc)
Sample chart order:
To start norepinephrine drip as follows: 4 mg norepinephrine + 250 D5W x 38 cc/hr (0.2 mcg/kg/min or 10 mcg/min in a 50 kg patient)
Titrate by 5 cc/hr to maintain BP >90/60
33 To compute for the current dose given a certain infusion rate, use the following formula:
Dose mcg / min =Infusion rate (cc/hr) x concentration (mcg/cc) kg weight (kg) 60 min/hr
B. METHOD 2: Short-Cut Method
Computation for Norepinephrine Drip Rate based on Desired Dose