Acetaminophen

Question 1

What is the MOA of acetaminophen?

Answer 1

Central anti-prostaglandin effect (very LITTLE peripheral nerve activity):

• antipyretic
• pain reduced via blockade of: NMDA receptor activation in CNS; AND Substance P in the SC!

Question 2

What is the class of acetaminophen?

Answer 2

Non-opioid Analgesic

Question 3

What does Acetaminophen LACK, which is why it is NOT a true NSAID? This makes it a good choice for?

Answer 3

lacks peripheral activity- weak anti-inflammatory action
Good choice for :
-PUD
-Pediatric patients
-Pts who need well fxning platelets
-Preggers safe

Question 4

Tell me about the potency of acetaminophen w/r/t ASA

Answer 4

Similar potency as ASA (in single analgesic doses, has same time-effect curve)

Question 5

What is the dose of acetaminophen?

Answer 5

325-650mg Q4-6 hours

Question 6

Howis acetaminophen metabolized?

Answer 6

conjugated and hydroxylated to inactive metabolites; very little excreted unchanged by the kidneys

Question 7

What is the IV dose of acetaminophen?

Answer 7

1000mg IV (or 1gram) over 15min Q4-6 hours

Question 8

What is the max dose IV of acetaminophen?

Answer 8

4 grams! can get liver and kidney damage

Question 9

What is a major side effect of acetaminophen and renal?

Answer 9

renal toxicity:

• renal papillary accumulation of metabolites can cause renal cell necrosis
• may be a development of ESRD
• but NSAIDS are higher risk of renal tox!

Question 10

What can overdose of acetaminophen cause?

Answer 10

serious or fatal HEPATIC INJURY

• liver can only metabolize a limited amt of the hapatotoxic metabolite N-acetyl-p-benzoquinone with Glutathione
• when glutathione outnumbered by OD of acetaminophen hepatic injury occurs
• safe dose EVEN LOWER in ETOH
• increased tox with Isoniazid

Question 11

What medication can you give in an overdose of acetaminophen? What are the time constraints?

Answer 11

-Acetylcysteine can substitute for glutathione and prevent hepatic injury if given within 8 hours of OD