Surgery and General Anesthesia Pharm

Question 1

Opioids

Answer 1

Most widely used med for post-op pain

Bolus injection dosing most common, continuous infusions are dangerous

All are hepatically metabolized to active and inactive metabolites

• these are eliminated in urine

Need dosing adjustments with severe liver disease

Question 2

Morphine

Answer 2

Rapid onset, duration of action 4-5 hours

IV 1-3 mg q5min

Neurotoxicities w/ renal insufficiency

-Myoclonus, confusion, coma, death

Relative CI w/ severe renal disease

Erratic GI absorption - have to give higher oral dose than IV

Question 3

Hydromorphone (Dilaudid)

Answer 3

Peak onset 30 mints

1/2 life: 2.4 hours

4-6X more potent than morphine

Question 4

Fentanyl

Answer 4

Synthetic morphine derivative - 100X more potent

No histamine release (no itchy); preferred w/ hemodynamic instability or bronchospams

Often used for procedural sedation - colonoscopy

IV for acute pain management

Transdermal is never for acute

Question 5

Meperidine

Answer 5

Short-term management of acute pain

CI w/ MAOI - lower seizure threshold

Dysphoric effect, less effective opioid

Slower metabolism rate in elderly or liver/renal failure

CI w/ PCA pump - risk for active metabolite accumulation

Question 6

Opioid Side Effects

Answer 6

Somnolence

Brainstem depression - respiratory drive

Hypotension

Urinary retention

N/V

GI slowing - constipation, ileus

Histamine release - MC after morphine; don’t get w/ fentanyl

Question 7

Transition from IV to oral

Answer 7

Switch to oral once patient can tolerate PO

Calculate 24 hour opioid consumption - use equianalgesic chart

PO analgesic effect in 30-60 minutes

Switch to Oxycodone, hydrocodone (2 MC); Hydromorphone and morphine

Question 8

Oxycodone Oral Combinations

Answer 8

Oxycodone/acetaminophen (Percocet)

Oxycodone/ibuprofen (Combunox)

Schedule II drug

Question 9

Hydrocodone Oral Combinations

Answer 9

Hydrocodone/acetaminophen (Lortab, Vicodin)

Hydrocodone/ibuprofen (Vicoprofen)

Question 10

Opioids to use in impaired renal function

Answer 10

Hydromorphone and oxycodone = inactive metabolites

Fentanyl - inpatient only

Question 11

Opioid Reversal

Answer 11

Naloxone (Narcan)

Reverse respiratory depression

IV, IM, subQ, endotracheally

0.04-0.4 mg initially, repeat until response or 0.8 total

Question 12

NSAIDs

Answer 12

Can reduce needed opioid dose

Caution with kidney impairment

IV Nonselective have higher incident rate of GI bleed

Question 13

Nonselective NSAIDs - IV and PO

Answer 13

IV: Ketorolac, ibuprofen

PO/PR: ibuprofen, Diclofenac, Ketoprofen

Question 14

Selective NSAIDS

Answer 14

No IV formulation selective

PO/PR: Celecoxib (Celebrex)

Question 15

Other non-opioid adjunctive medications

Answer 15

Ketamine - NMDA receptor inhibitor, causes hallucinations

Acetaminophen - CI hepatic failure, can give + NSAIDs

Lidocaine - Class 1 antiarrhythmic - most effective for major abdominal surgery

Magnesium sulfate - NMDA receptor antagonist, rarely used despite effectiveness

Question 16

Anesthesia Induction Drugs

Answer 16

Propofol - MC used; causes BP and cardiac output drop

-has antiemetic properties

Etomidate: no vasodilation or antiemetic effects, increased risk of death and cortisol biosynthesis inhibitor

Ketamine: used w/ hemodynamic instability - cardiac stimulation

-get hallucinations

Question 17

Anesthesia Maintenance Drugs

Answer 17

Inhaled: volatile (seroflurane/desfluane), nitrix oxide (in combo w/ volatile, never alone)

IV anesthetics: propofol, remfentanil

Question 18

Anesthesia Emergence Drugs

Answer 18

To blunt autonomic hyper-response (tachycardia, HTN, bronchospasm, laryngospasm)

Short term narcotics

Beta blocker

Lidocaine

Question 19

Propofol (Diprivan)

Answer 19

Nonbarbiturate

Rapidly metabolized in liver and excreted in urine

Good for long duration surgery due to rapid onset, clearance, and reversibility (shut off drip)

40 second onset, 1-3 hour duration

Versed is a more potent amnesiac

SE: rapid microorganism growth, HOTN, hypertonia/movement, respiratory depression

Question 20

Ketamine

Answer 20

Dissociative anesthesia - patient appears awake but is unresponsive to sensory stimuli

Commonly used in pediatric surgery, high risk geriatrics, and shock

Can give IM (peds), and provides cardiac stimulation

Use limited due to hallucinations

30 second onset, 5-10 minute duration

Question 21

Anesthetic Gas Keys

Answer 21

Reversibility matters here

The more soluble the gas, the longer the elimination period

NO and desflurane are the shortest acting

Disrupt normal synaptic transmission by altering neurotransmitter release, re-uptake, and binding to post-synaptic sites

Question 22

Minimum Alveolar Concentration (MAC)

Answer 22

Inhaled concentration where 50% of patients move in response to midline abdominal incision

Decreases with age

Question 23

Isoflurane

Desflurane

Sevoflurane

Nitrous Oxide

Answer 23

Isoflurane: Higher solubility, airway irritation, vasodilation and tachycardia

Desflurane: Lest well tolerated in airway - not for mask induction

Sevoflurane: Well-tolerated, no tachycardia

Nitrous Oxide:MAC 105% - never monotherapy

-No malignant hypothermia risk

Question 24

-curonium, Cisatracurium

Answer 24

Nondepolarizing Neuromuscular Blocking Drugs

Reversible ACh binding

Pancuronium longest acting with vagolytic effect

Mivacurium shortest acting

Train of four to monitor

Question 25

NMBD Reversal

Answer 25

Acetylcholine esterase inhibitor - neostigmine, edrophonium

• get ACh accumulation @ neuromuscular junction

Sugammadex - no anticholinergic effect

-Reverses vecuronium and rocuronium