Convert mcg/min to mL/hr

Formulas

First, convert micrograms per minute (mcg/min) to milligrams per hour (mg/hr).

$\frac{D×60 min}{1000 mcg}$
• D = Dose (mcg)

Then use the dosage formula to calculate rate.

$\frac{O×V}{A}$
• O = Dose ordered
• V = Volume of dose available
• A = Dose available

Example

1. Start an infusion of nitroglycerin at 10 mcg/min, then titrate to chest pain.  The nitroglycerin is to be mixed as 50 mg in 250 milliliters (mL) of D5W.  First, convert mcg/min to mg/hr.

• Dose (mcg) = 10 mcg
$\frac{\mathrm{10 mcg}×60 min}{1000 mcg}$

The answer is 0.6 mg/hr. Then use the dosage formula. To complete the problem

• Dose ordered (mg) = 0.6 mg
• Volume of dose available (mL) = 250 mL
• Dose available (mg) = 50 mg
$\frac{\mathrm{0.6 mg}×\mathrm{250 mL}}{\mathrm{50 mg}}$

2. Start an infusion of Levophed® (norepinephrine) at 4 mcg/min then titrate to blood pressure. Pharmacy has mixed 4 mg of Levophed® in a 1,000 mL bag of D5W. First, convert mcg/min to mg/hr.

• Dose (mcg) = 4 mcg
$\frac{\mathrm{4 mcg}×60 min}{1000 mcg}$

The answer is 0.24 mg/hr. Then use the dosage formula. To complete the problem

• Dose ordered = 0.24 mg
• Volume of dose available = 1000 mL
• Dose available = 4 mg
$\frac{\mathrm{0.24 mg}×\mathrm{1000 mL}}{\mathrm{4 mg}}$