Surgery: Drugs

Question 1

mechanism of action: Plavix (clopidogrel)

Answer 1

irreversibly blocks P2Y12 component of ADP receptors on the platelet surface > prevents activation GPIIb/IIIa receptor > reducing platelet aggregation. platelets blocked by clopidogrel are affected for the remainder of their lifespan (~7-10 days).

Question 2

dosing for morphine

Answer 2

IV: 2.5-5mg q4-6hrs opioid naive.
PO: 15-30mg q4hrs for immediate release.

Question 3

drug interactions: morphine

Answer 3

may decrease antiplatelet effect of P2Y12 inhibitors

Question 4

onset of action: morphine

Answer 4

PO (immediate release): ~30 min.

IV: 5 to 10 min

Question 5

duration of action: morphine

Answer 5

Immediate-release (tablet, oral solution, injection): 3-5 hours
Extended-release capsule and tablet: 8-24 hours (formulation dependent)
Epidural or intrathecal (Single dose): Up to 24 hours
Suppository: 3-7 hours

Question 6

time to peak (plasma): morphine

Answer 6

tablets, PO, epidural: 1 hour.
Extended release tablets: 3-4 hours
Suppository: 20-60 minutes
SubQ: 50-90 minutes
IM: 30-60 minutes
IV: 20 minutes

Question 7

dosing of oxycodone

Answer 7

initial: (immediate release) 5-15mg q4-6 hrs, (extended release) 10mg q12 hrs.

Question 8

onset of action: oxycodone

Answer 8

immediate release: 10-15 min

Question 9

duration of action: oxycodone

Answer 9

immediate release: 3-6 hrs

extended release: up to 12 hrs

Question 10

time to peak (plasma): oxycodone

Answer 10

immediate release: 1.2-1.9 hrs.

extended release: 4-5 hrs

Question 11

dosing of acetaminophen (PO)

Answer 11

immediate-release:
regular strength: 650 mg q4-6 hrs; max 3250 mg QD
extra strength: 1000 mg q6 hrs; max 3000 mg QD. extended-release: 1300 mg q8 hrs; max 3900 mg QD.

Question 12

dosing of acetaminophen (rectal)

Answer 12

650 mg q4-6 hrs; max 3900 mg QD

Question 13

dosing of acetaminophen (IV)

Answer 13

<50 kg: 12.5 mg/kg q4 hrs or 15 mg/kg q6 hrs; maximum single dose: 15 mg/kg/dose (≤750 mg/dose); maximum daily dose: 75 mg/kg/day (≤3.75 g/day)

≥50 kg: 650 mg q4 hrs or 1,000 mg q6 hrs; maximum single dose: 1,000 mg/dose; maximum daily dose: 4 g/day

Question 14

adverse reactions: acetaminophen

Answer 14

skin rash, nephrotoxicity (with chronic overdose), hypersensitivity rxn (rare)

Question 15

onset of action: acetaminophen

Answer 15

PO: <1 hr.
IV: 5-10 min (analgesia), within 30 min (antipyretic)

Question 16

duration of action: acetaminophen

Answer 16

PO/IV: (analgesia) 4-6 hrs.

IV: (antipyretic) ≥6 hrs

Question 17

stool softeners (surfactants)

Answer 17

docusate sodium (colace), docusate calcium

Question 18

bulk-forming laxatives

Answer 18

psyllium, methylcellulose, polycarbophil, wheat dextrin

Question 19

osmotic agents

Answer 19

polyethylene glycol (miralax), lactulose, sorbitol, glycerin

Question 20

stimulant laxatives

Answer 20

bisacodyl (dulcolax), senna (senokot)

Question 21

dosing of docusate sodium (colace)

Answer 21

100mg BID