Acetaminophen

Question 1

Brand Name

Answer 1

Offirmev

Question 2

Broad Category

Answer 2

Analgesic / Antipyretic / Non-opioid adjunct

Question 3

Pharm class

Answer 3

Para-aminophenol derivative

Question 4

MOA

Answer 4

Exact MOA not fully understood

Central Pathways: activates descending serotonergic inhibitory pathways, inhibits COS in brain without binding to active site, and it may inhibit a central COX-3 variant (animal models)

Receptor modulation: at spinal cord, antagonizes neurotransmission by NMDA, substance P, and NO pathways
metabolites modulate transient receptor potential vanilloid 1 (TRPV1) and TRPA1 channels, and stimulate CB1 in rostral ventromedial medula

Question 5

Indications / clinical uses

Answer 5

Pain mgmt
Opioid-sparing ERAS
Antipyretic

Question 6

IV dosing Adults > 50kg

Answer 6

1000 mg infused over 15 min q6h
OR
650mg q4h

Question 7

MAX dose > 50 kg

Answer 7

4 grams in 24 hours

Question 8

IV dosing < 50 kg adult

Answer 8

15 mg/kg q6h

Question 9

MAX dose <50 kg

Answer 9

3 grams in 24 hours

Question 10

Formulation considerations

Answer 10

Contains mannitol

Question 11

Chronic Alcoholic MAX dose

Answer 11

2 grams

Question 12

Onset

Answer 12

15 mins

Question 13

Peak

Answer 13

1 hour

Question 14

Duration

Answer 14

4-6 hours

Question 15

PO first pass?

Answer 15

minimal

Question 16

Common SE

Answer 16

N/V
HA
Insomnia

Question 17

Precautions / avoidance

Answer 17

Hepatic Impairment / Acute disease
chronic alcoholism
Chronic malnutrition
Severe hypovolemia
Severe renal impairment

Question 18

Major concern

Answer 18

Hepatotoxicity
- acetylcysteine
- Leading cause of acute fulminant hepatic failure often requiring transplant

Question 19

Metabolism

Answer 19

Extensive Hepatic
- CYP2E1 (causes toxic metabolite NAPQI)
- glucuronidation (Primary) glutathione mediated
- sulfation

Question 20

Elimination

Answer 20

Renal

Question 21

Vd consideration

Answer 21

Moderate
- moderate tissue distribution
- CNS penetration

Question 22

Clearance Considerations

Answer 22

Reduced clearance in
- hepatic dysfunction
- severe malnutrition
- chronic alcohol