Unit 06: drugs

Question 1

what is yohimbine

Answer 1

Alpha 2 receptor antagonist

• can reverse effects of alpha2 receptor agonists
• drugs can reverse sedation and most cardiovascular effects

Question 2

what is atipamezole

Answer 2

Alpha 2 receptor antagonist

• can reverse effects of alpha2 receptor agonists
• drugs can reverse sedation and most cardiovascular effects

Question 3

what is dexmedetomidine

Answer 3

sedative

• alpha-2 agonist

Question 5

what is diazepam

Answer 5

sedative

benzodiazepine

Question 6

what is medetomidine

Answer 6

• mixture of 2 enantiomers - dexmedetomidine and levomedetomidine

(dexmedetomidine is the biologically active)

• when ued at moderate dosages with general anesthetic there is usually no significant change in BP

Question 7

what is flumazenil

Answer 7

• GABA R antagonist: competitive inhibitor of benzodiazepine site
• reverses overall effects of benzodiazepines
• used to reverse benzodiazepine overdose

Question 8

what is fentanyl

Answer 8

mu receptor agonist with intense analgesic effect, known as the “full Mu agonist”.

Question 9

what is pentazocine

Answer 9

opioid

kappa agonist with good analgesic effect

also produces a weak effect at mu receptors, making it act like an antagonist to other mu opioids

Question 11

what is loperamide?

Answer 11

• reduce propsulive gut motility in large bowel, decrease gut secretions and cause constiction of anal spincter
• stool remians in large colon longer which allows more water to be reabsorbed - potent constipating effect

Question 12

what is Diphenoxylate?

Answer 12

• reduce propsulive gut motility in large bowel, decrease gut secretions and cause constiction of anal spincter
• stool remians in large colon longer which allows more water to be reabsorbed - potent constipating effect

Question 14

Ether

Answer 14

early general anesthetic

• inhalant introducted in 1846
• demonstrated little respiratroy or cardiovascular depression and relatively non-toxic
• does have pungent odour and expolsive properties
• now used as starter fluid in combustion engines

Question 15

chloroform

Answer 15

CHCl3

early general anesthetic

• inhalant introducted in 1847
• non pungent odor and non explosive
• can be hepatotoxic resulting in severe cardiovascular depresion
• was preferred inhalant until almost 1950

Question 16

what is nitrous oxide

Answer 16

• AKA laughing gas
• weak CNS depressant, cannot produce general anesthesia even when 100% NO is administered
• used to reduce amount of other inhalants requires, speeds up uptake of gas anesthetics
• can be used of analgesia, no respiratory depression is assocaited with it suse as longa s you dont go above 50-60% which would dispalce O2 ausing asphyxiation
• little effect on cardiovascular system at lower conc
• adverse effects include increasing uptake of other anesthetics, and effects on GI system (formation of gas pockets causing bloating), N2O outflow can cause hypoxia during recovery
• todau used in dental clinics, hospitals and few veterinary clinics to reduce amount of hydrocarbon anesthetic required

Question 17

what is cyclopropane?

Answer 17

• early general anesthetic
• used to be most populat
• associated with explosions in operating room bc has flammable properties

Question 18

sodium pentobarbital

Answer 18

• barbiturate that is effective and relatively safe if used with caution (narrow safty margin)
• elimination of drug requries hepatic metabolism- metabolism is too slow in emergency situations
• injectible anesthetic

Question 19

halogenated hydrocarbon anesthetics

Answer 19

• isoflurance, sevoflurane and desflurane
• all inhalants

Question 20

what is sodium thiopental

Answer 20

• barbiturate adiminstered via IV
• ultra short duration with rapid induction and recovery rate

The physiological effects on the CNS include dose dependent depression in 10-30 seconds, and unconsciousness for 1½ - 3 minutes.

If a partial dose is administered, it is likely to cause excitement as opposed to induction.

Question 21

what is propofol

Answer 21

one of the most popular intravenous anesthetics

• offers sedation and anesthesia but has poor analgesic effects
• mainly used for induction and has short duration (2-5min) so can be utilized during short painful procedures
• premedation should be used first sot hat less propofol is needed for respiratory induction- resulting in less blood pressure depression
• half life of drug increases with age so can be problematic in geriatirc patients

Question 22

what is propofol

Answer 22

• one of most popular intravenous anesthetics
• offers sedation and anestheria btu has poor analgesic effects
• short duration of action, should also use a premedication so less propofol is needed (minimize effects of blood pressure depression
• actcs by slowing dissocition of GABA from tis receptor- longer inhibition of action potentials
• can cause apnea for 30-60sec and dose dependent respiratroy despression but not usually a problem
• can cause dope dependent depression of blood rpessure causing peripheral vasodilation

Question 23

what is ketamine

Answer 23

dissociateive anesthetic, only IV anesthetic with analgesic properties

GABA and NMDA antagonist (GABA is inhibitory so if u ihibt that get inc SNS activity)

• can increase HR and BP due to SNS stimulation, can use this to advantage in patietns in cardiovascular shock
• can rise intracranial pressue causing seizures, hallucinations and excitment during recovery phase
• use with diazepam to rpoduce rapid, smooth induction with little effect on cardiovascualr system

*never used alone

Question 24

what is dantrolene

Answer 24

administer is patietn is suspected to be experiencing malignant hyperthermia (potential effect of halothane)

Question 25

what is Haloethane

Answer 25

- inhalant anesthetic - 25% is metabolized, hepatotoxic metabolites - can cause hypoxia and increased CO2 causing epinephrine release, deos not change HR but CO can decrease (reduces BP) - can cause arrhythmias due to sensitivity of the myocardium to epinephine - can depress thermoregulation resulting in hypothermia or malignant hyperthermia (very dangerous but need to ahve a genetic mutation for that) - can result in liver damage bc hepatotoxic

Question 26

what is isoflurane

Answer 26

- most common anesthetic - alsmot no toxicity since very little is metabolized - low solubiltiy in tissues so moves in and out of bdoy quickly - causes less depression of CO than halothane but does ccase vasodilation which can result in dose dependent drop in blood pressure - post anesthetic hepatic necrosis has been reported in 1/500,000 pateints - less potent than halothane and has pungent odour (only real drawback)

Question 27

what is sevoflurane

Answer 27

- Inhalant anesthetic - less stable than isoflurane, breaks fown when exposed to CO2 abosrbent in anestheic machine amkign it worse when the oxygen flow rate is low - as result nephrotoxic ocmound is release "compound A" (MOA somewhat unknwon) - human metbaolize up to 5% producing fluride ions that are released and thought to damage renal tubules, this sint supported by data

Question 28

what is tubocurarine

Answer 28

- non depolarizing NM blocker - also idnuced histamine relase which lowers bp

Question 29

what is pancuronium

Answer 29

NM blocker agent - replaced tubocurarine but tends ot be vagolytic (inhibits pSNS signaling in the vagus nerve causing increased HR) - has been replaced with rocuronium, mivacurium and atracirium

Question 30

what are currently used NM blocker agents

Answer 30

rocuronium, mivacurium and atracurium - differ mainly in duration of action and route of elimination

Question 31

what is atracurium

Answer 31

NM blocker agent - used to prevent eye movement during ocular surgery - chemically similar to acetylcholine and competitively blocks nicotinic receptors at neuromuscular junction - causes intense relaxation or paralysis of voluntary muscle - intensity of effect depends on dose - safer than other non depolarizing blockers like tubucurauine and pancuronium and depolarizing blockers like succinyl chlone which is now barely used

Question 32

what is cisatracurium

Answer 32

- same advantages of atracurium but less liekly to cause adverse effects

Question 33

what is procain

Answer 33

- first cocaine substitute - main local anesthetic until lidocaine - known as Novocain and still used but less frequently - problem is that its an ester which is cleaved by plasma esterases and has a short duration of action (15-60min) esters are more allergenic then amides but are sometimes still use wen rapid onset but short duration is desired

Question 34

what is lidocaine

Answer 34

- most widely used local anesthetic - numerous routes of administration and applications - overdose can cause drowsiness or seizures, muscle twitching, possible cardiac arrest and death - usualy administered via injection and has duration of action of 30-60 min - onset following infiltration is approx 3 min - can aso be topical gel or topical spray

Question 35

what is bupivacaine

Answer 35

- antoher widely used local anesthetic - slower onset (15min) but logner duration (2-4 hours) - longer effects come with greater cardiovascular toxicity if an IV bolus forms, can cause severe ventricular arrhythias - lecobupivacaine is the s(-) enantiomer and does not dsitribute well to CNS and heart - \*\*levobupivacaine has replaced bupivacaine for regional, IV use in human medicine.