Drugs

Question 1

What causes the excitatory behavior from opioids?

Answer 1

• hypothalamus effects
• indirect activation of dopaminergic receptors

Question 2

How do opioids cause respiratory depression?

Answer 2

• affect medullary and pontine respiratory centers
• reduce sensitivity and change threshold for PaCO2 by chemoreceptors –> leads to CO2 retention

Question 3

Is opioid-induced bracycardia responsive to atropine?

Answer 3

yes, vagally mediated

Question 4

Which opioids are contraindicated in mast cell tumors and why?

Answer 4

• morphine, methadone, meperidine
• cause histamine release with marked hypotension

Question 5

After epidural morphine administration how long does it take until analgesic effects start?

Answer 5

30 min

Question 6

What is the oral transmucosal bioavailability of buprenorphine?

Answer 6

50%

Question 7

List injectable opioids from most likely to least likely to cause vomiting

Answer 7

morphine > hydromorphone > methadone > fentanyl > buprenorphine > butorphanol

Question 8

How may naloxone be beneficial in shock?

Answer 8

reduced splanchnic capacitance –> improved venous return and CO + MAP

Question 9

Why is IV diazepam use discouraged compared to midazolam?

Answer 9

contains propylene glycol
* irritates blood vessels –> phlebitis, thrombosis
* propylene glycol toxicity from prolonged administraiton –> metabolic acidosis, hyperosmolality, neurologic abnormalities, organ dysfunction

Question 10

What is the MOA of alpha-2 agonists?

Answer 10

Gi/o G-protein-couple receptor binding –> inhibits adenylyl cycle –> decrased cAMP –>

stimulates K-channels and NaH exchange, inhibits Ca++ channels

inhibits release of norepinephrine

Question 11

What part of the brain do alpha-2 agoists affect?

Answer 11

locus ceruleus (brainstem)

Question 12

How do alpha-2 agonists affect blood flow in the following tissues?

• brain
• heart
• kidneys
• skin
• muscles
• intestines

Answer 12

• brain&raquo_space; decreased cerebral blood flow - can cause hypoxia
• heart, kidneys&raquo_space; preserved
• skin, muscles, intestines&raquo_space; decreased

Question 13

What can be coadministered to reduce cardiovascular side effects of alpha-2 agonists?

Answer 13

Ca+ channel blockers

Question 14

How do alpha-2 agonists cause hyperglycemia?

Answer 14

bind to alpha-adrenoreceptors on the beta cells of the islets of Langerhans –> inhibits insulin release

increase growth hormone release

Question 15

How do alpha-2 agonists cause diuresis?

Answer 15

• inhibit ADH release
• inhibit ADH’s effect on collecting ducts
• inhibit release of renin
• increase release of atrial natriuretic factor

Question 16

What other receptors do alpha-2 agonists bind to?

Answer 16

Imidazoline receptors

Question 17

What is the function of the COX 1 pathway?

Answer 17

• hemostasis
• renal perfusion
• gastric mucous and bicarbonate secretion

Question 18

Where are COX-3 located and what are 2 NSAIDs that cause COX-3 inhibition?

Answer 18

cerebral cortex
inhibition decreases prostaglandin E2 synthesis

acetaminophen and metamizole

Question 19

How are NSAIDs metabolized and excreted?

Answer 19

• cytochrome P450 enzyme
• glucuronidation or oxidation
• excreted via biliary route and urien

Question 20

How does gastric NSAID injury differ to intestinal NSAID injury?

Answer 20

gastrc: decreased bicarbonate secretion and mucus production
intestines: enterohepatic recylcing and consequent prolonged and repeated exposure

Question 21

How do COX1 and COX2 differ in their hemostatic effects?

Answer 21

COX 1 –> TXA –> PLT aggregation and vasoconstriction

COX 2 –> prostacyclin –> anticoagulant and vasodilation

Question 22

What is the mechanism of action of Grapiprant?

Answer 22

EP4 prostaglandin receptor antagonist

Question 23

What are clinical signs of methemoglobinemia?

Answer 23

• cyanosis
• facial edema
• prolapsed conjunctival membranes
• brown blood and urine
• tachypnea and dyspnea

Question 24

What is the mechanism of action of Gabapentin?

Answer 24

presynaptic alpha2-delta1 subunit inhibition of the Ca-channel –> leads to decreased neurotransmitter release

Question 25

What is the mechanism of action of Tramadol?

Answer 25

mu-agonist via its metabolite M1 (cytochrome P450 pathway)

some norepinephrine and serotonin reuptake inhibition

Question 26

What is the MOA of trazodone

Answer 26

• serotonin reuptake inhibitor
• antagonist of 5HT2A and 5HT2C
• inhibits serotonin transporter and serotonin type 2 receptor
• additionally: H1, alpha-1, and T-type Ca channel blocker

Question 27

Why is trazodone contraindicated in glaucoma patients?

Answer 27

mydriasis –> can trigger acute crisis