Acetaminophen Dosing for a 7-Month-Old Infant
For a 7-month-old infant, administer acetaminophen 10-15 mg/kg per dose every 4-6 hours, with a maximum of 60 mg/kg per day (not exceeding 5 doses in 24 hours). 1
Weight-Based Dosing Calculation
To determine the exact milliliter dose, you must first know the infant's weight:
- Standard concentration: Acetaminophen oral suspension is typically 160 mg/5 mL (32 mg/mL) 1
- Dose calculation: Multiply the infant's weight in kg by 10-15 mg, then divide by 32 mg/mL to get milliliters 1, 2
Example Calculations:
- For a 7 kg infant: 70-105 mg per dose = 2.2-3.3 mL every 4-6 hours 1, 3
- For an 8 kg infant: 80-120 mg per dose = 2.5-3.75 mL every 4-6 hours 1, 3
- For a 9 kg infant: 90-135 mg per dose = 2.8-4.2 mL every 4-6 hours 1, 3
Frequency and Maximum Daily Limits
- Dosing interval: Every 4-6 hours as needed 1, 2
- Maximum daily dose: 60 mg/kg per day 1
- Maximum number of doses: No more than 5 doses in 24 hours 1
The 4-hour minimum interval is critical to prevent accumulation and toxicity, while the 6-hour maximum interval maintains therapeutic effect 2, 4.
Route of Administration
Oral suspension is strongly preferred over rectal suppositories for a 7-month-old because oral formulations provide more rapid and consistent absorption 1. Rectal acetaminophen has erratic absorption, meaning some infants may receive inadequate pain relief while others risk drug accumulation with repeated dosing 1.
Critical Safety Considerations
- Never exceed 60 mg/kg per day - chronic overdosing (>140 mg/kg/day for several days) carries risk of serious hepatotoxicity 2
- Single ingestions exceeding 10 times the recommended dose are potentially toxic and require immediate medical evaluation 2
- For infants under 3 months, acetaminophen is the only recommended analgesic, but dosing should be supervised by a physician 1, 2
Common Pitfalls to Avoid
- Do not use adult formulations - ensure you have pediatric suspension (160 mg/5 mL), not adult extra-strength formulations 1
- Avoid combination products - many cold/flu medications contain acetaminophen; using these alongside acetaminophen suspension can lead to unintentional overdose 1
- Do not round doses excessively - while rounding up to 15% is acceptable for convenience, larger rounding increases toxicity risk 5, 1