Pediatric Medication Dosing: Parent's Complete Safety Guide

Why Pediatric Dosing Is Different

The phrase "children are not small adults" is foundational in pediatric pharmacology. Medicine metabolism, distribution, and elimination differ dramatically across developmental stages — and dosing errors are among the most dangerous medication errors in pediatrics.

Key physiological differences:

Body composition: Higher total body water in neonates (80% vs 60% in adults); lower fat stores; lower protein binding

Liver enzymes: CYP enzyme expression develops gradually; CYP3A4 peaks at age 1-5, then decreases to adult levels; neonates cannot metabolize many medicines efficiently

Kidney function: Neonatal GFR is 2-4 mL/min/1.73m² (vs 120 in adults); reaches adult levels by age 1-2

Blood-brain barrier: Less complete in young infants; medicines enter CNS more readily (opioid sensitivity)

Absorption: Gastric pH higher in infants (affects acid-labile medicine stability); slower gastric emptying

---

Weight-Based Dosing: The Foundation

Most pediatric medicines are dosed by mg/kg up to a maximum adult dose. Weight-based dosing accounts for children's smaller body mass and higher metabolic rate.

Critical rule: Always use current weight, not age, as primary dosing parameter.

Example: Amoxicillin for otitis media

Dose: 40-90 mg/kg/day divided every 8-12 hours

Child weighs 20 kg

Dose range: 800-1800 mg/day

If given TID: 267-600 mg per dose

Maximum: Adult dose (usually 500-875 mg TID) — do not exceed

Practical tip: Keep your child's weight in pounds AND kilograms. 1 kg = 2.2 lbs. A 44-lb child = 20 kg.

---

OTC Medications: Common Parent Questions

#

Acetaminophen (Tylenol)

Dose: 10-15 mg/kg every 4-6 hours (max 5 doses/24 hours)

Max daily dose: 75 mg/kg/day or 4000 mg/day (whichever is less)

Product concentration: Infant drops (160 mg/5 mL) and children's liquid (160 mg/5 mL) are now the SAME concentration — reduces dosing confusion

Not for: Neonates under 2 months without medical guidance

Danger: Acetaminophen is the leading cause of acute liver failure in the US — overwhelmingly from unintentional overdose (multiple combination products taken simultaneously)

#

Ibuprofen (Advil, Motrin)

Dose: 5-10 mg/kg every 6-8 hours

Not for: < 6 months of age; dehydration (renal risk); bleeding or platelet disorders

Reye's syndrome note: Ibuprofen does NOT cause Reye's syndrome (aspirin does) — it is safe for viral illnesses

#

Aspirin

Avoid in children under 18 with viral illness — risk of Reye's syndrome (rare but potentially fatal liver/brain toxicity)

Exception: Kawasaki disease treatment under physician direction

#

Cough and Cold Medications

FDA guidance: OTC cough/cold products should NOT be used in children under 4 years (some say under 6)

No efficacy evidence in young children

Risk of serious adverse events: convulsions, rapid heart rate, death (particularly antihistamines and decongestants)

#

Antihistamines

Diphenhydramine (Benadryl): Not recommended under 2; sedating; cognitive impairment

Cetirizine (Zyrtec), loratadine (Claritin): 2nd generation; safer; approved age 2+

---

Prescription Pediatric Medications: Key Points

#

Antibiotics

Never use leftover antibiotics — incomplete courses promote resistance; dosing may be wrong for current illness

Amoxicillin: First-line for otitis media, strep pharyngitis, most community pneumonia

Azithromycin (Z-pack): Convenient but overused; resistance concerns; cardiac risk in patients with prolonged QT

Fluoroquinolones: Generally avoided in children under 18 — concerns about cartilage toxicity (though increasingly used when benefit outweighs risk)

Tetracyclines: Avoid under 8 — permanent tooth discoloration

#

Compounding

When commercial formulations are unavailable, compounding pharmacies prepare custom concentrations. Verify compounded preparations from a state-licensed pharmacy for quality assurance.

---

Medication Administration Tips

Oral liquids:

Use the measuring device that comes with the medication (oral syringe, dosing cup)

Never use kitchen spoons — teaspoon varies by 2-7 mL

Place oral syringe inside cheek (buccal mucosa) — not back of throat

Tablets:

Children 6+ can often swallow small tablets with practice

Check if tablets can be crushed or capsules opened (not all can)

Mix in small amount of food if needed — verify with pharmacist for specific medicine

Eye/ear drops:

Warm to body temperature (hold in hands 2 minutes) — reduces discomfort

Eye drops: pull down lower lid; don't touch dropper to eye