Week 7 Handout Flashcards
What is Dexmedetomidine?
S-enantiomer of medetomidine, an alpha agonist
Dexmedetomidine is used for sedation, analgesia, and anxiolysis.
What is the pH of Dexmedetomidine?
7.4
What is the mechanism of action for Dexmedetomidine?
CNS alpha receptor agonist and systemic vasodilation
What are the cardiovascular effects of Dexmedetomidine?
Hypotension and bradycardia
What is the loading dose of Dexmedetomidine?
1 mcg/kg over 10 min
What is the duration of action for Dexmedetomidine after stopping the infusion?
10-30 min
Does Dexmedetomidine cause respiratory depression?
No, it does not cause respiratory depression
What is Etomidate?
Carboxylated imidazole derivative
What is the mechanism of action for Etomidate?
GABA modulator
What is the emergence time for Etomidate after bolus administration?
5-15 min
What are the adverse effects of Etomidate?
- Pain on injection
- Thrombophlebitis
- Nausea and vomiting
- Myoclonia
What is the primary use of Ketamine?
Induction of anesthesia
What type of anesthesia does Ketamine provide?
Dissociative anesthesia
What is the pKa of Ketamine?
7.5
What is the induction dose of Ketamine when administered IV?
2-4 mg/kg
What are the cardiovascular effects of Ketamine?
Circulatory stimulant, indirect sympathomimetic
What is the primary mechanism of action for Propofol?
GABA agonist
What is the standard induction dose of Propofol?
1-2 mg/kg
What are the concerns regarding Propofol’s use?
- Susceptible to bacterial contamination
- PRIS (Propofol Infusion Syndrome)
What is the half-life of Midazolam?
Short half-life
What is the primary effect of opioids?
Analgesia
What is the active metabolite of Morphine?
M6G (active metabolite) and M3G (inactive metabolite)
What is the onset time for Morphine when given IV?
20 min
What is Fentanyl primarily used for?
Profound dose-dependent analgesia
Does Fentanyl have an active metabolite?
No, it does not have an active metabolite
What is the primary disadvantage of Meperidine?
Accumulation of normeperidine can lead to CNS excitation and seizures
What is the pH of Etomidate?
8.1
What effect does Propofol have on cerebral blood flow?
Decreases CBF and CMRO2
What is the mechanism of action for opioids?
Inhibit ascending transmission of nociception and activate descending pain control pathways
What effect does the active metabolite of the drug have on seizure threshold?
Lowers seizure threshold and induces CNS excitability
The active metabolite is normeperidine, which has an analgesic effect but can cause CNS issues.
What is the elimination half-life of normeperidine compared to its parent drug?
Significantly longer
This can lead to accumulation and CNS excitation.
What are the effects of kappa receptor stimulation in relation to this drug?
Shivering reduction in general and epidural anesthesia
This is an important consideration in anesthesia management.
Which patient populations should exercise caution with normeperidine?
- Patients with renal failure
- Elderly patients
- Chronic use in cancer patients
High doses may be required in chronic pain management.
What are the characteristics of remifentanil?
- Piperidine-derived opioid with ester link
- No active metabolite
- Water soluble
- Rapid onset and ultrashort duration
These properties allow for rapid recovery after infusion.
What is the elimination half-life of remifentanil?
8-20 minutes
This facilitates quick recovery after anesthesia.
Why is bolus dosing of remifentanil not recommended in the preop and postop phases?
Potential for respiratory depression and muscle rigidity
Alternative analgesic therapy is advised in these phases.
What is buprenorphine classified as?
Potent partial agonist opioid
It primarily binds to mu receptors and has a unique pharmacological profile.
What is the duration of action for buprenorphine?
8 hours
It shows slow dissociation from the receptor.
What is a key characteristic of butorphanol?
Highly lipophilic opioid
It acts as a kappa agonist and mu antagonist, producing analgesia with a ceiling effect.
What are the uses of nalbuphine?
- Treat pain
- Treat pruritus induced by epidural morphine
- Treat respiratory depression from other opioids
It has a ceiling effect for respiratory depression.
What is naloxone?
Pure opioid antagonist
It reverses respiratory depression and opioid analgesia through competitive antagonism.
What is naltrexone used for?
Alcohol disorder treatment
It prevents the euphoric effects of opioids and has a longer duration of action than naloxone.
What is the primary mechanism of action for ketorolac?
Inhibiting cyclooxygenase enzymes
This makes it effective for mild to moderate pain.
What is the maximum daily dose of acetaminophen for adults?
4000 mg/day
Exceeding this dose can lead to hepatotoxicity.
What is the definition of Minimum Alveolar Concentration (MAC)?
The alveolar concentration of an inhaled anesthetic that prevents movement in 50% of patients in response to a standardized stimulus
MAC is a measure of anesthetic potency.
What factors influence MAC?
- Decreases by 6% per decade of age
- Unaffected by species, sex, or anesthesia duration
These factors are important for tailoring anesthetic dosage.
What is the Train of Four (TOF) response indicative of?
Neuromuscular blockade levels
TOF measures the response of muscle to electrical stimulation, helping assess recovery.
What is a Phase II block?
Desensitization block occurring after large doses of depolarizing neuromuscular blockers
It shows a fade in response, unlike Phase I.
What is the primary method of elimination for inhalation anesthetics?
Alveolar ventilation
This is crucial for effective anesthesia management.
What are the contraindications for inhalation anesthetics?
- Potentiate neuromuscular blocking agents
- Catecholamine-induced arrhythmias
- Malignant hyperthermia
These contraindications highlight the need for careful patient selection.
What are the effects of nitrous oxide on the cardiovascular system?
Stimulates sympathetic nervous system, may mask myocardial depression
In patients with CAD or severe hypovolemia, this effect may be significant.
What is the primary concern with sevoflurane?
Degradation into nephrotoxic compound A
Monitoring renal function is important during its use.
What is the respiratory effect of isoflurane?
Causes respiratory depression with less pronounced tachypnea
It is an effective bronchodilator.
What is the mechanism of action for succinylcholine?
Depolarizes nicotinic receptors, causing transient activation followed by neuromuscular blockade
It does not cross the blood-brain barrier.
What is succinylcholine composed of?
2 acetylcholine (ACh) molecules; quaternary ammonium structure; water-soluble.
Does succinylcholine cross the blood-brain barrier?
No, it does not cross the blood-brain barrier.
What is the primary action of succinylcholine?
Depolarizes nicotinic receptors, causing transient activation followed by neuromuscular blockade.
What is the onset time for succinylcholine?
Within 3 minutes.
What is the duration of action for succinylcholine?
5-10 minutes.
What is the plasma half-life of succinylcholine?
2-4 minutes.
How is succinylcholine metabolized?
By plasma cholinesterase (hydroxylation), then further into succinic acid and choline.
What is the intravenous dose range for succinylcholine?
0.5 - 1.5 mg/kg; ED95 ~0.30 mg/kg.
In which special population is succinylcholine contraindicated?
Patients with a history of malignant hyperthermia.
What are the side effects of succinylcholine?
- Myalgias * Hyperkalemia * Possible malignant hyperthermia trigger.
What can cause prolonged effects of succinylcholine?
Pseudocolinesterase deficiency.
What is rocuronium bromide?
A monoquaternary aminosteroid neuromuscular blocker.
What are the onset and duration of action for rocuronium?
Onset: rapid (45-90 sec); Duration: intermediate (30-60 min).
What is the elimination half-life of rocuronium?
60-120 minutes.
What is the intravenous dose range for rocuronium?
0.6 – 1.2 mg/kg.
What is vecuronium bromide?
A monoquaternary aminosteroid neuromuscular blocker developed from pancuronium.
What is the onset time for vecuronium?
2-4 minutes.
What is the elimination half-life of vecuronium?
51-90 minutes in healthy adults.
What is the induction dose for vecuronium?
0.1 mg/kg.
What is cisatracurium besylate?
A nondepolarizing muscle relaxant, three times more potent than atracurium.
What is the mechanism of action of cisatracurium?
Competes with acetylcholine for binding to nicotinic receptors at the motor endplate.
What is the elimination process for cisatracurium?
Hofmann elimination and non-specific esterases.
What is atracurium besylate?
A competitive bisquaternary neuromuscular blocker.
What is the onset time for atracurium?
1.2 to 2.8 minutes.
What are the adverse effects of atracurium?
- Histamine release * Hypotension * Bradycardia.
What is neostigmine?
An anticholinesterase agent.
What is the dose range for neostigmine?
25-75 mcg/kg.
What is the onset time for neostigmine?
5-15 minutes.
What NMBA cannot be reversed by neostigmine?
Succinylcholine.
What is sugammadex?
A drug that reverses neuromuscular blockade but is not an anticholinesterase.
What is the onset time for sugammadex?
1-2 minutes.
What are the common side effects of sugammadex?
- Nausea * Vomiting * Allergy * Hypertension * Headache.
What is the role of anticholinergics in the context of NMBA reversal?
To prevent parasympathetic side effects of anticholinesterase drugs.
What is the dose range for atropine?
7-15 mcg/kg.
What is glycopyrrolate?
A quaternary ammonium compound used to prevent excessive parasympathetic effects.
What is the onset time for glycopyrrolate?
1-2 minutes IV.
What are common side effects of anticholinesterase drugs?
- Bradycardia * Arrhythmias * Hypotension * Bronchoconstriction * Hypersalivation.
What is the onset time for Glycopyrrolate when administered IV?
1-2 min
Glycopyrrolate has a duration of action of 2-4 hours.
What is the primary route of excretion for Glycopyrrolate?
Feces, urine (85% in urine after 48 hrs)
Glycopyrrolate is excreted mostly as unchanged.
What is the dose for Scopolamine when applied for preoperative sedation?
1.5 mg applied behind ear
Scopolamine has a duration of action of 3 days.
What is the mechanism of action for Ephedrine?
Stimulates both alpha and beta receptors directly and indirectly
Causes the release of endogenous catecholamines.
What is the drug of choice for maternal hypotension after regional anesthesia?
Phenylephrine
Ephedrine was previously used but phenylephrine is now preferred.
What is the onset time for Phenylephrine?
Immediate
Phenylephrine has a duration of action of 5-20 min.
What is the primary use of Esmolol?
Beta 1 selective Beta blocker
Used to decrease heart rate and blood pressure perioperatively.
What is the standard IV dose for Metoprolol?
5 mg every 5 min, max 15 mg
Metoprolol is used to manage arrhythmias and decrease heart rate.
What is the ratio of alpha to beta blocking effects in Labetalol?
7:1
Labetalol is used to treat hypertension without affecting uterine blood flow.
What is the standard adult dose of Cefazolin for surgical prophylaxis?
2g IV (3g if patient weight >120kg)
Administer within 60 minutes before incision.
What type of bacteria does Cefazolin target?
Staphylococcus aureus and enteric gram-negative bacilli
Commonly used for surgical prophylaxis.
What is the mechanism of action for Dexamethasone?
Inhibition of the nucleus tractus solitarius, serotonin reduction, and prostaglandin synthesis
Used to manage PONV.
What is the duration of action for Ondansetron?
4-6 hrs
Most effective for vomiting rather than nausea.
What is the long half-life of Palonosetron?
44 hrs
Preferable for PDNV.
What type of receptor does Aprepitant block?
Neurokinin 1 Receptor
FDA-approved for PONV.
What are the side effects of Droperidol?
Extrapyramidal side effects
Contraindicated in Parkinson’s disease.
What is the primary action of Midazolam in the context of nausea?
Reduces dopamine’s emetic effects
Used as a sedative near the end of surgery.
What caution should be noted with Metoclopramide?
Can cause dyskinesia and extrapyramidal effects
Contraindicated in Parkinson’s disease and bowel obstructions.
