What is the dosage calculation for acetaminophen (Tylenol) and ibuprofen (Advil) for infants and children with fever, cough, vomiting, and loose stools?

Pediatric Dosing for Fever, Cough, Vomiting, and Loose Stools

For fever management in infants and children, use acetaminophen 10-15 mg/kg every 4-6 hours (maximum 5 doses/24 hours) or ibuprofen 10 mg/kg every 6-8 hours (maximum 3 doses/24 hours), with ibuprofen as the preferred first-line agent based on superior fever reduction duration. 1, 2, 3

Fever Management

Acetaminophen (Tylenol) Dosing

• Standard dose: 10-15 mg/kg per dose, administered every 4-6 hours 4, 2
• Maximum frequency: Up to 5 doses in 24 hours 5, 4
• Practical example: For a 14 kg child, give 140-210 mg per dose 6
• Onset of action: Rapid temperature reduction begins within 1 hour, with maximum effect at approximately 3 hours 2

Ibuprofen (Advil/Motrin) Dosing

• Standard dose: 10 mg/kg per dose, administered every 6-8 hours 1, 3
• Maximum frequency: Up to 3 doses in 24 hours 3
• Practical example: For a 14 kg child, give 140 mg per dose 6
• Age restriction: Only for children ≥6 months of age 1

Choosing Between Acetaminophen and Ibuprofen

• Ibuprofen should be used first as it provides equivalent initial fever reduction to acetaminophen but maintains fever control longer 1, 3
• After the first dose, ibuprofen 10 mg/kg equals acetaminophen 15 mg/kg in effectiveness, but ibuprofen requires less frequent dosing 1
• Combination therapy (both medicines alternating) provides an additional 2.5 hours without fever over 24 hours compared to ibuprofen alone, and 4.4 hours compared to acetaminophen alone 3
• If using both medicines together, meticulously record all dose times to avoid exceeding maximum recommended doses, as 8-11% of parents inadvertently overdose when using combination therapy 3

Critical Dosing Pitfalls

• Underdosing is common: 27% of parents give less than 10 mg/kg acetaminophen, resulting in inadequate fever control 5
• Overdosing occurs: 12% of parents give ≥20 mg/kg acetaminophen per dose 5
• Weight-based dosing is more accurate than age-based dosing for ensuring proper dose ranges 4

Cough Management

When Cough Suggests Croup

• Immediate intervention: If stridor at rest, retractions, or difficulty breathing are present, administer racemic epinephrine 0.5 mL/kg of 1:1000 solution (maximum 5 mL) via nebulizer 6
• Alternative: L-epinephrine 0.5 mL/kg of 1:1000 solution up to 5 mL if racemic epinephrine unavailable 6

When Cough Suggests Pneumonia

• Pleuritic chest pain with cough indicates possible pneumonia requiring chest radiography 6
• If pneumonia confirmed: Amoxicillin 45-90 mg/kg/day divided into 2 doses for 10 days 7
• For mild-moderate community-acquired pneumonia: 45 mg/kg/day in 2 doses 7
• For severe pneumonia or high pneumococcal resistance areas: 90 mg/kg/day in 2 doses 7
• Maximum daily dose: 4000 mg (4 g) 7

When Cough Suggests Atypical Pneumonia (Mycoplasma)

• Azithromycin: 10 mg/kg on day 1, followed by 5 mg/kg/day once daily on days 2-5 8
• Alternative: Clarithromycin 15 mg/kg/day in 2 doses 8
• For children >7 years: Doxycycline 2-4 mg/kg/day in 2 doses 8

Vomiting Management

Oral Rehydration Strategy

• First-line therapy: Reduced osmolarity oral rehydration solution (ORS) for mild to moderate dehydration 8
• Dosing for mild-moderate dehydration: 50-100 mL/kg ORS over 3-4 hours 8
• Ongoing replacement during vomiting:
  • Children <10 kg: 60-120 mL ORS per vomiting episode, up to ~500 mL/day 8
  • Children >10 kg: 120-240 mL ORS per vomiting episode, up to ~1 L/day 8

When Oral Intake Fails

• Nasogastric ORS administration may be considered for children with normal mental status who cannot tolerate oral intake 8
• Intravenous fluids (lactated Ringer's or normal saline) are indicated for severe dehydration, shock, altered mental status, or ileus 8
• In children with ketonemia, initial IV hydration may be needed before tolerating oral rehydration 8

Severe Dehydration Protocol

• IV isotonic crystalloid boluses per current fluid resuscitation guidelines until pulse, perfusion, and mental status normalize 8
• Administer up to 20 mL/kg body weight boluses 8
• Malnourished infants: Use smaller-volume frequent boluses of 10 mL/kg due to reduced cardiac output capacity 8

Loose Stools (Diarrhea) Management

Rehydration as Primary Treatment

• ORS is the cornerstone of diarrhea management regardless of cause 8
• Same dosing as vomiting management above 8
• Ongoing replacement during diarrhea:
  • Children <10 kg: 60-120 mL ORS per diarrheal stool, up to ~500 mL/day 8
  • Children >10 kg: 120-240 mL ORS per diarrheal stool, up to ~1 L/day 8

Appropriate ORS Products

• Acceptable commercial formulations: Pedialyte Liters, CeraLyte, Enfalac Lytren 8
• Do NOT use: Apple juice, Gatorade, or commercial soft drinks for rehydration 8

Feeding During Diarrhea

• Continue breastfeeding throughout the illness 8
• Resume age-appropriate normal diet after rehydration is complete 8
• Children on lactose-containing formula can tolerate the same product in most instances 8
• Diluted formula provides no benefit 8

When Antibiotics Are Needed

• Antimicrobial treatment should be modified or discontinued when a specific organism is identified 8
• Most acute infectious diarrhea in children does not require antibiotics 8

Key Safety Considerations

• Temperature monitoring: Children on appropriate therapy should show clinical improvement within 48-72 hours; if not, reevaluation is necessary 7
• Hypothermia risk: Three cases of hypothermia (temperature <35.6°C) occurred with acetaminophen in one study, though this was rare 1
• Complete antibiotic courses even if symptoms improve before completion 7
• Hospital admission indicators: Persistent severe symptoms, pneumonia, bronchiolitis, or unidentified severe viral illness warrant hospitalization 3