Peds dose of iv n acetylcystine
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Here is the pediatric IV N-acetylcysteine (NAC) dosing from the Harriet Lane Handbook (23rd ed):
IV N-Acetylcysteine — Pediatric Dosing (Acetaminophen Toxicity)
The standard regimen is a 3-bag protocol over 21 hours total:
| Bag | Dose | Max | Duration |
|---|---|---|---|
| 1 — Loading | 150 mg/kg | 15 g | over 60 min |
| 2 — Maintenance 1 | 50 mg/kg | 5 g | over 4 hours |
| 3 — Maintenance 2 | 100 mg/kg | 10 g | over 16 hours |
Total duration: 21 hours (unless extended — see below).
When to extend beyond 21 hours
- If the patient develops liver failure, continue the 100 mg/kg/16 hr infusion until:
- Resolution of encephalopathy
- AST < 1,000 units/L
- INR < 2
Treatment Criteria (when to start NAC)
- Serum acetaminophen level above the possible toxicity line on the Rumack-Matthew nomogram after a single acute ingestion
- History of ingestion > 200 mg/kg or > 10 g (whichever is less) AND level unavailable or timing unknown
- Unknown timing or chronic/multiple ingestions: treat if acetaminophen level or AST is elevated
Note: See the Harriet Lane Formulary (Chapter 30) for weight-based drug dilution volumes for each bag. Oral NAC (140 mg/kg load, then 70 mg/kg q4h) is an alternative if IV is not available.
— The Harriet Lane Handbook, 23rd ed., p. 102
Should we require to dilute n acetylcystein
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Yes, IV N-acetylcysteine must be diluted before administration. Here's a summary:
IV N-Acetylcysteine Dilution Requirements
Why dilution is required
NAC is commercially available as a 20% solution (200 mg/mL), which is hyperosmolar and cannot be given undiluted IV — it must be diluted in D5W (5% dextrose) before infusion.
Standard dilution (3-bag protocol)
| Bag | Dose | Diluent | Volume |
|---|---|---|---|
| 1 — Loading (150 mg/kg over 1 hr) | Based on weight | D5W | ~200 mL in adults; weight-based in peds |
| 2 — Maintenance 1 (50 mg/kg over 4 hr) | Based on weight | D5W | ~500 mL in adults; weight-based in peds |
| 3 — Maintenance 2 (100 mg/kg over 16 hr) | Based on weight | D5W | ~1000 mL in adults; weight-based in peds |
Pediatric dilution — special consideration
In small children and infants, the standard adult dilution volumes can cause fluid overload (hyponatremia, seizures, death have been reported). The Harriet Lane Handbook specifically states:
"See Formulary for weight-based drug dilution volumes."
Weight-based dilution charts must be used in pediatrics — the diluent volume is scaled down according to the child's weight to avoid fluid overload.
A dose calculator and detailed pediatric dilution directions are available at Acetadote.com.
Anaphylactoid reactions and dilution rate
The loading dose (highest concentration, fastest rate) carries the greatest risk of anaphylactoid reactions (4–17% of patients). If a reaction occurs:
- Slow or stop the infusion temporarily
- Give diphenhydramine
- Restart at a slower rate once asymptomatic
- Do not permanently discontinue — fulminant liver failure has occurred after stopping NAC for anaphylactoid reactions
Bottom line: Yes, dilution in D5W is mandatory. In pediatric patients, use weight-based dilution tables (not adult standard volumes) to prevent dangerous fluid overload.
— Tintinalli's Emergency Medicine, p. 1297; Harriet Lane Handbook, 23rd ed., p. 102
Dilution of n acetylcysteine in peds
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Here is the complete pediatric IV NAC dilution protocol from Tintinalli's Emergency Medicine:
IV N-Acetylcysteine — Pediatric Dilution (Weight-Based)
Stock solution: 20% (200 mg/mL) — must be diluted to ~2% solution for peripheral IV infusion
Diluent: D5W (5% dextrose in water) or half-normal saline
Diluent: D5W (5% dextrose in water) or half-normal saline
⚠️ Standard adult dilution volumes will cause fluid overload and hyponatremia in children < 40 kg. Always use weight-based volumes.
Peds 21–40 kg
| Bag | Dose | Diluent Volume | Rate | Duration |
|---|---|---|---|---|
| Loading | 150 mg/kg | 100 mL D5W | — | 60 min |
| Maintenance 1 | 50 mg/kg | 250 mL D5W | 12.5 mg/kg/hr | 4 hr |
| Maintenance 2 | 100 mg/kg | 500 mL D5W | 6.25 mg/kg/hr | 16 hr |
Peds 5–20 kg
| Bag | Dose | Diluent Volume | Rate | Duration |
|---|---|---|---|---|
| Loading | 150 mg/kg | 3 mL/kg D5W | — | 60 min |
| Maintenance 1 | 50 mg/kg | 7 mL/kg D5W | 12.5 mg/kg/hr | 4 hr |
| Maintenance 2 | 100 mg/kg | 14 mL/kg D5W | 6.25 mg/kg/hr | 16 hr |
Adult (> 40 kg) — for reference
| Bag | Dose | Diluent Volume | Duration |
|---|---|---|---|
| Loading | 150 mg/kg | 200 mL D5W | 60 min |
| Maintenance 1 | 50 mg/kg | 500 mL D5W | 4 hr |
| Maintenance 2 | 100 mg/kg | 1000 mL D5W | 16 hr |
Key takeaways:
- For < 20 kg: use mL/kg-based volumes, not fixed volumes
- For 21–40 kg: use intermediate fixed volumes (half the adult volumes)
- Monitor closely for hyponatremia and fluid overload in all small children
- Total infusion time: 21 hours (extend if liver failure — see prior note)
- For oral NAC: dilute 20% stock to a 5% solution before administration
— Tintinalli's Emergency Medicine, Table 190-2
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