For a 70‑kg male, what is the dose in µg·kg⁻¹·h⁻¹ when two 100 µg ampoules are mixed with 49 mL of normal saline and infused at 2 mL per hour?

Dose Calculation

For this 70 kg male receiving 2 ampules of 100 mcg mixed with 49 mL normal saline and infused at 2 mL/hour, the dose is approximately 0.057 mcg/kg/min (or 3.4 mcg/kg/hour).

Step-by-Step Calculation

Total Drug Amount

• 2 ampules × 100 mcg = 200 mcg total

Final Volume

• 200 mcg + 49 mL NS = 50 mL total volume

Concentration

• 200 mcg ÷ 50 mL = 4 mcg/mL

Delivery Rate

• Infusion rate: 2 mL/hour
• Drug delivery: 2 mL/hour × 4 mcg/mL = 8 mcg/hour

Weight-Based Dosing

• 8 mcg/hour ÷ 70 kg = 0.114 mcg/kg/hour
• Converting to per minute: 0.114 ÷ 60 = 0.0019 mcg/kg/min (approximately 0.002 mcg/kg/min)

Clinical Context

If this is an epinephrine infusion (the most common medication given in 100 mcg ampules for continuous infusion), this dose of 0.002 mcg/kg/min falls well below the typical therapeutic range:

• Standard epinephrine infusion range: 0.1–1.0 mcg/kg/min for shock after volume resuscitation 1
• Your calculated dose: 0.002 mcg/kg/min

This represents only 2% of the minimum recommended starting dose, suggesting either:

1. A calculation or mixing error has occurred
2. The medication is not epinephrine
3. The intended clinical effect requires verification

Standard Epinephrine Preparation

For comparison, guideline-recommended epinephrine infusions use concentrations of:

• 1 mg in 250 mL (4 mcg/mL) infused at 1–4 mcg/min initially 2
• 1 mg in 100 mL for pump administration at 30–100 mL/hour (5–15 mcg/min) 2

Critical Safety Point: If this is intended as a vasoactive infusion for hemodynamic support, the current preparation and rate will not achieve therapeutic effect. Verify the medication, indication, and intended dosing with the prescribing physician immediately.