Opioid/non-opioid Drugs

Question 1

Morphine

Answer 1

Active metabolite

Histamine release

Slow onset due to pKa (completely ionized) & low lipid solubility

Question 2

Codeine

Answer 2

Morphine pro-drug- metabolized to morphine in liver by demethylation

Antitussive activity-cough syrup

Question 3

Hydromorphone

Answer 3

PK profile similar to morphine but more potent

No active metabolite- better in renal failure

More lipid soluble than morphine=neuraxial

Question 4

Methadone

Answer 4

Good bioavailability w/oral- well absorbed in GI

Long half-life

Unique NMDA antagonism

Little to no euphoria

Question 5

Meperidine

Answer 5

Neurotoxic metabolite- seizures in renal failure w/accumulation

Contraindicated in MAO-I -weakly blocks Presynaptic serotonin reuptake

Very effective in post anesthesia rigors- learn receptor!! Low dose (12.5-25 mg)

Question 6

Fentanyl

Answer 6

Highly lipophilic

Significant first pass uptake by lungs

Question 7

Sufentanil

Answer 7

Most potent phenylpiperidine

Expect apnea and rigidity

Shorter half-life than fentanyl

Question 8

Alfentanil

Answer 8

Short acting, rapid onset

Due to low Vd and highly non-ionized & high protein binding lol

Question 9

Remifentanil

Answer 9

Very short acting- 5 minutes

Plasma/tissue esterases

Need rapid recovery with intense surgical stimulation at end of case

Administer longer acting priori to emergence due to hyperalgesia

Rapid tolerance-intraop

Highly emetogenic-Midazolam can mitigate

Question 10

Tramadol

Answer 10

Synthetic codeine analog with weak mu-activity

Analgesia from inhibition of norepi/serotonin reuptake

Since analgesia is not related to mu- the resp depression (rare) can be reversed with naloxone without loss of analgesia

Question 11

Buprenorphine

Answer 11

Partial mu agonist

Long duration- 8 hours (slow dissociation from receptor)

Ceiling effect

Increasing use in addiction treatment

Question 12

Nalbuphine

Answer 12

Agoinst-antagonist

Reverse resp depression and maintain analgesia

Mu- antagonist

Kappa- agonist

Also used for management of opioid related pruritis in neuraxial anesthesia

Question 13

Naloxone

Answer 13

Antagonist of mu-kappa-delta

Oxymorphone derivative

Duration is significantly less than most agonists

Rapid hepatic metabolism and clearance

Risks:
Withdrawal, severe pain, increased sympathetic outflow (think cardiac), pulmonary edema and death

Question 14

Naltrexone

Answer 14

Similar antagonism to naloxone with longer duration -24 hours due to active metabolite

Question 15

Naltrexone

Answer 15

Similar antagonism to naloxone with longer duration -24 hours due to active metabolite

Question 16

Ketoralac

Answer 16

Non-selective COX-1 COX-2 inhibitor

30mg IV 60mg IM

Duration 4-6 hours

Always consult surgeon

Do not give in renal failure, with caution in elderly

Question 17

Acetaminophen

Answer 17

Weak inhibitor of prostaglandins synthesis similar to COX-2 but DOES NOT suppress inflammation

Activation of central descending pain modulation pathways

Highly hepatotoxic in overdose

Newest recommendation is max 3g/24hr in adults due to variance in metabolism btwn individuals

Question 18

Celecoxib

Answer 18

Selective COX-2