Tox: Tylenol

Tylenol
-rapidly absorbed, peaks 2h except delayed absorption with tylenol-propoxyphene and Tylenol Extended Relief
-liver > sulfation and glucuronidation and cyt p450 oxidation > napqi > hepatic glutathione > nontoxic cmpd > renal excretion
-hepatic glutathione stores depleated, NAPQI accumulates > centrilobular necrosis
-alcoholics and aids pts have low glutathione stores; alcs and anticonvulsant and antitb drugs rev up p450
-NAC blocks binding of NAPQI to hepatic prtns, glutathione precursor, directly reduces napqi to tylenol

si/sx
1) day 1 - no sx, or anorexia, n/v, malaise
2) day 2-3 - n/v improve; RUQ (hepatotox), inc ast/alt/bili
3) day 3-4 - fulminant hep failure; lactic acidosis, coagulopathy, renal failure, encepahlopathy, recurrent n/v
-toxicity if ingest > 140 mg/kg or >7.5 g in adult in 24h
-single large od, use Rumack-Matthew Normogram, based on serum tylenol level 4-24 hr after time of ingestion; 4h level > 150 mic/dl is toxic; after 24 hr, a detectable tylenol level or presence of inc transaminases may predict toxicity
-multiple ingestions - assume a single ingestion at the earliest possible point in time and use normogram
-Tylenol ER - add 2 hr to time of ingestion and interpret the normogram

Rx:
-ABC's
-tylenol level within 4 to 24 hrs of ingestion
-lytes, glc, bun, cr, ast/alt, cbc, pt
-activated charcoal 1g/kg
-NAC po or ng tube 140 mg/kg load, then 70 mg/kg q 4hr x 17 additional doses, can give immediately after charcoal, safe in pregnancy; dilute in a beverage and give with zofran or reglan
-correct coagulopathy/acidosis
-treat cerebral edema

Dispo:
-nontoxic tylenol levels based on nomogram d/c from ED if no other drug ingestion and not