How is the Rumack-Matthew nomogram used?

Plot acetaminophen level (y-axis) vs hours post-ingestion (x-axis). Levels above the treatment line (200 mg/L at 4h, 100 mg/L at 8h, 25 mg/L at 16h) require NAC. US nomogram adds 25% safety margin—treatment threshold is 150 mg/L at 4h. NAC is 100% effective if started within 8 hours of ingestion.

When is the nomogram not applicable in acetaminophen overdose?

Nomogram not applicable: unknown ingestion time, staggered/repeated overdose over multiple hours or days, extended-release formulations (re-check level 4 hours after first level), presentation >24 hours post-ingestion (use clinical/biochemical criteria), massive ingestion (level may be >treatment line at any time).

Acetaminophen Overdose Rumack-Matthew Nomogram

Apply the Rumack-Matthew nomogram to determine N-acetylcysteine treatment necessity in acetaminophen overdose based on 4-hour post-ingestion plasma level and time since ingestion.

Use the full interactive calculator below, or

Acetaminophen Overdose Rumack-Matthew Nomogram

Frequently Asked Questions

How is the Rumack-Matthew nomogram used?

When is the nomogram not applicable in acetaminophen overdose?