Pediatrics Dose Calculation Formula

Pediatrics Dose Calculation Formula is a tool for computing the pediatric dosage for a child of a given weight. 

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Dose Calculation Formula

Unit Measurement Converter

Quantity: From: micrograms (ug) milligrams (mg) grams (g) kilograms (kg) To: micrograms (ug) milligrams (mg) grams (g) kilograms (kg) Convert

Body Weight-Based Dose Calculation

Weight (kg):
Recommended Dose (mg/kg):
Calculate

Dose Calculation Based on Concentration

Drug Concentration (mg/mL):
Recommended Volume/Mass (mL/g):
Calculate

Dose Calculation Based on Tablet/Capsule Count

Total Dose (mg):
Dose per Tablet/Capsule (mg):
Calculate

Dose Calculation Based on Body Surface Area

Body Surface Area (m²):
Recommended Dose (mg/m²):
Calculate

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In pediatrics, drug dosages are typically determined based on a child’s body weight (mg/kg) or body surface area (mg/m2). It is crucial to accurately convert body weight from pounds to kilograms using the conversion factor of 1 kg = 2.2 lb before calculating dosages based on body weight. Dosage instructions are often expressed as either mg/kg/day or mg/kg/dose. However, orders written in the format “mg/kg/d” can be confusing and require additional clarification from the prescribing healthcare provider.

Pediatrics Dose Calculation Formula

Infant Dose Calculation Formula: mg/μg per kilogram per day

dose (volume) = (dose (mg/μg) × child's weight) / (concentration × frequency)

• child's weight is given in kg
• concentration is usually given in mg/mL
• frequency means the number of times a chosen medication is given per day. bid – Bis in die – “Twice a day”,  frequency has a value of 24.

Pediatrics Dose Calculation Formula: mg/μg per kilogram per dose

dose (volume) = (dose (mg/μg) × child's weight) / concentration

Infant Dose Calculation Formula mg/μg per day

dose (volume) = dose (mg/μg) / (concentration × frequency)

Peds dosing calculator: mg/μg per day

dose (volume) = dose (mg/μg) / concentration

Dose Frequency Abbreviations

Dose frequency abbreviations can be somewhat perplexing, as they all have their origins in the Latin language. In this concise medical dictionary, we offer a handy reference:

• qd – Quaque die – “Once a day”
• bid – Bis in die – “Twice a day”
• tid – Ter in die – “Three times a day”
• qid – Quater in die – “Four times a day”
• q4h – Quaque 4 hora – “Every 4 hours”
• q6h – Quaque 6 hora – “Every 6 hours”
• q8h – Quaque 8 hora – “Every 8 hours”
• hs – Hora somni – “At bedtime”
• ac – Ante cibum – “Before meals”
• pc – Post cibum – “After meals”

Pediatrics Dose Calculation Formula examples

Tylenol Pediatric Dose Calculation (example)

Let’s assume the prescribed dose is 10 mg/kg, and the child’s weight is 20 kg. The concentration of the Tylenol solution is 120 mg/5 mL, and it is prescribed to be given every 4 hours.

Using the formula:

Dose (volume) = (Dose (mg) × Child’s Weight) / (Concentration × Frequency)

Dose (volume) = (10 mg/kg × 20 kg) / (120 mg/5 mL × 4 times/day)Dose (volume) = (200 mg) / (480 mg/day)Dose (volume) = 0.4167 mL per dose (rounded to the nearest decimal).

So, the child should receive approximately 0.42 mL of Tylenol per dose every 4 hours.

Dexamethasone Pediatric Dose Calculation (example)

Suppose the prescribed dose of dexamethasone is 0.2 mg/kg, and the child’s weight is 25 kg. The concentration of the dexamethasone solution is 4 mg/mL, and it is prescribed to be given once daily.

Using the formula:

Dose (volume) = (Dose (mg) × Child’s Weight) / (Concentration × Frequency)

Dose (volume) = (0.2 mg/kg × 25 kg) / (4 mg/mL × 1 time/day)Dose (volume) = (5 mg) / (4 mg/day)Dose (volume) = 1.25 mL per dose.

Therefore, the child should receive 1.25 mL of dexamethasone once daily.

Doxycycline Pediatric Dose Calculation (example)

Let’s say the prescribed dose of doxycycline is 2 mg/kg, and the child’s weight is 30 kg. The concentration of the doxycycline suspension is 25 mg/5 mL, and it is prescribed to be given every 12 hours.

Using the formula: Dose (volume) = (Dose (mg) × Child’s Weight) / (Concentration × Frequency)

Dose (volume) = (2 mg/kg × 30 kg) / (25 mg/5 mL × 2 times/day)Dose (volume) = (60 mg) / (50 mg/day)Dose (volume) = 1.2 mL per dose.

Thus, the child should receive 1.2 mL of doxycycline every 12 hours.

Amoxiclav Pediatric Dose Calculation (example)

Suppose the prescribed dose of amoxiclav is 20 mg/kg per dose, and the child’s weight is 15 kg. The concentration of the amoxiclav suspension is 250 mg/5 mL. Using the formula:

Dose (volume) = (Dose (mg/kg) × Child’s Weight) / ConcentrationDose (volume) = (20 mg/kg × 15 kg) / (250 mg/5 mL)Dose (volume) = (300 mg) / (250 mg/5 mL)

Dose (volume) = 3 mL per dose. Therefore, the child should receive 3 mL of amoxiclav per dose.

Paracetamol (Acetaminophen): Pediatric Dose Calculation (example)

Let’s assume the prescribed dose of paracetamol is 15 mg/kg per dose, and the child’s weight is 18 kg. The concentration of the paracetamol solution is 120 mg/5 mL. Using the formula:

Dose (volume) = (Dose (mg/kg) × Child’s Weight) / Concentration

Dose (volume) = (15 mg/kg × 18 kg) / (120 mg/5 mL)Dose (volume) = (270 mg) / (120 mg/5 mL)Dose (volume) = 6.25 mL per dose. Thus, the child should receive 6.25 mL of paracetamol per dose.

Zosyn (Piperacillin-Tazobactam) Pediatric Dose Calculation (example)

Suppose the prescribed dose of Zosyn is 100 mg/kg per dose, and the child’s weight is 20 kg. The concentration of the Zosyn solution is 2.25 g/50 mL. Using the formula:

Dose (volume) = (Dose (mg/kg) × Child’s Weight) / ConcentrationDose (volume) = (100 mg/kg × 20 kg) / (2.25 g/50 mL)

Dose (volume) = (2000 mg) / (2.25 g/50 mL)Dose (volume) = 888.89 mL per dose (rounded to the nearest decimal). Therefore, the child should receive approximately 888.89 mL of Zosyn per dose.

Clindamycin pediatric dose calculator (example)

Let’s say the prescribed dose of clindamycin is 10 mg/kg per dose, and the child’s weight is 12 kg. The concentration of the clindamycin solution is 150 mg/mL. Using the formula:

Dose (volume) = (Dose (mg/kg) × Child’s Weight) / ConcentrationDose (volume) = (10 mg/kg × 12 kg) / (150 mg/mL)

Dose (volume) = (120 mg) / (150 mg/mL)Dose (volume) = 0.8 mL per dose. Thus, the child should receive 0.8 mL of clindamycin per dose.

FAQ

How to turn the dose in mL to mg?

To convert a dose in milliliters (mL) to milligrams (mg), you need to know the concentration of the medication, which is typically expressed as mg per mL. Then, you can use the following formula:

Dose (mg) = Dose (mL) x Concentration (mg/mL)

Here’s a step-by-step guide:

1. Identify the Dose in Milliliters (mL): This is the volume of the medication you have, expressed in milliliters.
2. Determine the Concentration (mg/mL): Check the medication label or prescription to find the concentration, which tells you how many milligrams of the medication are present in each milliliter of the solution.
3. Apply the Formula: Multiply the dose in milliliters by the concentration in milligrams per milliliter: Dose (mg) = Dose (mL) x Concentration (mg/mL)

For example, let’s say you have a medication with a concentration of 50 mg/mL, and you need to administer a 3 mL dose:

Dose (mg) = 3 mL x 50 mg/mL = 150 mg

How to turn the dose in mg to mL?

To convert a dose in milligrams (mg) to milliliters (mL), you need to know the concentration of the medication, which is typically expressed as mg per mL. Then, you can use the following formula:

Dose (mL) = Dose (mg) / Concentration (mg/mL)

Here’s a step-by-step guide:

1. Identify the Dose in Milligrams (mg): This is the amount of medication you have, expressed in milligrams.
2. Determine the Concentration (mg/mL): Check the medication label or prescription to find the concentration, which tells you how many milligrams of the medication are present in each milliliter of the solution.
3. Apply the Formula: Divide the dose in milligrams by the concentration in milligrams per milliliter: Dose (mL) = Dose (mg) / Concentration (mg/mL)

For example, let’s say you have a medication with a concentration of 100 mg/mL, and you need to administer a 250 mg dose:

Dose (mL) = 250 mg / 100 mg/mL = 2.5 mL