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Paramedic Drug Math: Formulas and Practice Problems

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Paramedic drug math uses three formulas: volume to give = desired dose divided by the concentration on hand, weight-based dose = dose per kg times weight, and infusion rate in mL/h = dose per minute times 60 divided by the concentration. Learn those, always convert to the same units first, and almost every calculation on the paramedic exam or in the ambulance falls into place.

This post walks through each formula, shows how to handle mcg/min and mcg/kg/min drips, drops per minute and dextrose concentrations, then gives 10 worked practice problems built on national EMS guideline doses. Two exam-style questions finish it.

The paramedic drug math formulas

You needFormula
Volume to give (mL)Desired dose / dose on hand x volume on hand
Weight-based doseDose per kg x weight in kg
Concentration of a bagTotal drug / total volume (convert mg to mcg first for drips)
Pump rate (mL/h) from mcg/minmcg/min x 60 / concentration in mcg/mL
Pump rate (mL/h) from mcg/kg/minmcg/kg/min x kg x 60 / concentration in mcg/mL
Gravity drip (gtt/min)Volume in mL x drop factor (gtt/mL) / time in minutes
Grams of dextrosePercent = grams per 100 mL
  • 1 g = 1,000 mg; 1 mg = 1,000 mcg; 1 kg = 2.2 lb.
  • Convert everything to the same unit before you divide.
  • With a 60 gtt/mL microdrip set, gtt/min equals mL/h.

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Volume to give: desired over have

Most push doses come down to one step. Write what you want, write what is in the syringe or vial per mL, and divide. If a vial holds 4 mg in 2 mL, the concentration is 2 mg/mL, so a 3 mg dose is 3 / 2 = 1.5 mL. Before you push it, ask whether the answer makes sense: a dose larger than the whole vial, or a fraction of a tenth of a mL, means a unit slipped.

Weight-based doses

Convert pounds to kilograms (divide by 2.2), multiply by the dose per kg, then check the maximum. Pediatric weight-based doses never go above the adult maximum, so a large teenager may simply get the adult dose. Use a length-based tape for children when you do not have a reliable weight.

Infusions: mcg/min and mcg/kg/min to mL/h and gtt/min

  1. Find the concentration: total mcg in the bag divided by total mL.
  2. Find the dose per minute: for mcg/kg/min, multiply by weight first.
  3. Multiply by 60 to get mcg per hour.
  4. Divide by the concentration to get mL/h for the pump.
  5. No pump? With a 60 gtt/mL set the drops per minute equal the mL/h; with another set, use the gravity formula.

Dextrose concentrations

Percent means grams in 100 mL. D10 is 10 g per 100 mL, D25 is 25 g per 100 mL and D50 is 50 g per 100 mL. A 25 g adult dose is therefore 250 mL of D10, 100 mL of D25 or 50 mL of D50. For children, 0.5 g/kg works out to 5 mL/kg of D10 or 2 mL/kg of D25.

10 paramedic drug math practice problems

  1. Push-dose epinephrine. Mix 1 mL of epinephrine 0.1 mg/mL with 9 mL of saline. What is the concentration, and how many mL is a 20 mcg dose? Answer: 0.1 mg = 100 mcg in 10 mL = 10 mcg/mL; 20 / 10 = 2 mL.
  2. Amiodarone in arrest. The order is 300 mg; the vial is 50 mg/mL. Answer: 300 / 50 = 6 mL.
  3. Fentanyl for pain. An 80 kg adult, 1 mcg/kg, supplied as 50 mcg/mL. Answer: 80 mcg (under the 100 mcg first-dose maximum); 80 / 50 = 1.6 mL.
  4. Intranasal midazolam for a seizure. An 18 kg child, 0.2 mg/kg, supplied as 5 mg/mL. Answer: 3.6 mg (under the 10 mg maximum); 3.6 / 5 = 0.72 mL.
  5. Naloxone for a child. A 12 kg toddler, 0.1 mg/kg IV, supplied as 0.4 mg/mL. Answer: 1.2 mg (under 2 mg); 1.2 / 0.4 = 3 mL.
  6. Adult dextrose. 25 g is ordered. How many mL of D10, and of D50? Answer: D10 has 10 g per 100 mL, so 250 mL; D50 has 50 g per 100 mL, so 50 mL.
  7. Pediatric dextrose. A 14 kg child, 0.5 g/kg of D10. Answer: 7 g; D10 is 0.1 g/mL, so 70 mL (5 mL/kg).
  8. Gravity drip. Magnesium 2 g in 100 mL over 15 minutes with a 10 gtt/mL set. Answer: 100 x 10 / 15 = 66.7, about 67 gtt/min (400 mL/h on a pump).
  9. Norepinephrine in mcg/min. 4 mg in 250 mL; the order is 8 mcg/min. Answer: 4,000 / 250 = 16 mcg/mL; 8 x 60 / 16 = 30 mL/h, or 30 gtt/min with a 60 gtt/mL set.
  10. Epinephrine in mcg/kg/min. A 70 kg adult at 0.1 mcg/kg/min; 1 mg in 250 mL. Answer: 1,000 / 250 = 4 mcg/mL; 0.1 x 70 = 7 mcg/min; 7 x 60 / 4 = 105 mL/h.

Exam-style questions

Question 1 · Trauma

An 80-kg adult has 30% total body surface area burns. Using the consensus formula of 2 mL × kg × %TBSA over 24 hours with half given in the first 8 hours, what is the initial hourly infusion rate?

  1. 200 mL/h
  2. 600 mL/h
  3. 150 mL/h
  4. 300 mL/h
Show the answer and rationale

Answer: D

  • A. 200 mL/h is the average over 24 hours and underestimates the early requirement.
  • B. 600 mL/h would deliver the first half in 4 hours, twice the intended rate.
  • C. 150 mL/h is the rate for the remaining 16 hours, not the first 8.
  • D. Correct. 2 × 80 × 30 = 4,800 mL in 24 hours; half (2,400 mL) over 8 hours is 300 mL/h.

The consensus formula gives 2 mL of lactated Ringer’s per kilogram per percent burned over the first 24 hours, half in the first 8 hours from the time of the burn: 2 × 80 × 30 = 4,800 mL, of which 2,400 mL is given over 8 hours, or 300 mL/h. Rates are then adjusted to urine output in hospital. Local protocols may use a simpler initial rate for adults with large burns.

Sources: NAEMT PHTLS, 10th ed.; ABA ABLS Provider Manual (2023); ABA Burn Shock Resuscitation Guideline (2024)

Question 2 · Medical, Obstetrics and Gynecology

A 3.5-kg infant born at home 2 days ago is jittery and feeding poorly, and the glucose is 28 mg/dL. IV access is in place. Which treatment is correct?

  1. 7 mL of dextrose 10% IV, followed by feeding
  2. 35 mL of dextrose 10% IV, followed by feeding
  3. 7 mL of dextrose 25% IV, followed by feeding
  4. Glucagon 1 mg IM in the thigh, followed by feeding
Show the answer and rationale

Answer: A

  • A. Correct. At 2 mL/kg of 10% dextrose, 3.5 kg needs 7 mL.
  • B. That is 10 mL/kg, the upper dose for older children. Newborns get 2 mL/kg.
  • C. The volume is right, but neonates under 1 month get no more than 10 to 12.5% dextrose.
  • D. Glucagon is less reliable with low glycogen stores, 1 mg is the larger pediatric dose, and IV access exists.

Symptomatic neonatal hypoglycemia is treated with dilute IV dextrose. NASEMSO gives newborns 2 mL/kg of 10% dextrose, and Merck gives up to 12.5% at 2 mL/kg over 10 minutes. Multiplying 3.5 kg by 2 mL/kg gives 7 mL. Stronger concentrations are avoided under 1 month of age. The glucose is rechecked if the infant has not improved, and the infant is kept warm and fed once able.

Sources: NASEMSO Model EMS Guidelines v3.0 (2022); Merck Manual Professional: Neonatal Hypoglycemia (2025)

The burn question is an infusion rate problem with an extra step. Total the 24-hour volume from the formula, take the half that goes in the first 8 hours, then divide by 8. The wrong answers come from using the 24-hour average or the second-period rate.

The newborn question turns dextrose concentration into a safety decision. A small volume per kilogram of the dilute solution gives a modest gram dose that a newborn's veins tolerate; the concentrated adult product and adult doses are the trap.

How to avoid drug math errors

  • Write the units at every step; if the units do not cancel to mL or mL/h, the setup is wrong.
  • Estimate before you calculate, then compare.
  • Watch for tenfold errors with decimals: write 0.5, never .5, and never add a trailing zero (5, not 5.0).
  • Say the dose, concentration and volume aloud and have a partner confirm.
  • For children, check the length-based tape and the adult maximum.

Frequently asked questions

What is the formula for paramedic drug calculations?

For a push dose, volume = desired dose / concentration on hand. For a drip, mL/h = dose per minute x 60 / concentration in mcg/mL, multiplying by weight first if the order is per kg.

How do you convert mcg/min to mL/h?

Multiply the mcg/min by 60 to get mcg per hour, then divide by the bag concentration in mcg/mL.

How many grams of dextrose are in D50?

D50 has 50 g per 100 mL, so a 50 mL syringe holds 25 g. D10 has 10 g per 100 mL, so 25 g is 250 mL.

Is drug math on the NREMT paramedic exam?

The National Registry does not publish item types by topic. Expect dosing decisions inside patient scenarios, so practice bare calculations and scenario questions both.

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Sources

  1. National Association of State EMS Officials. National Model EMS Clinical Guidelines, Version 3.0. March 2022. Bradycardia; Cardiac Arrest; Pain Management; Seizures; Opioid Poisoning; Hypoglycemia; Respiratory Distress; Shock. Link