112 Questions
Which medication has minimal detrimental effects when accidentally injected into an artery?
Etomidate
Which medication may stimulate ventilation independent of medullary centers?
Etomidate
Which medication is effective for acute insomnia but may lead to cognitive problems and mortality?
Benzodiazepines
Which medication has a built-in ceiling effect, preventing it from exceeding the physiologic maximum of GABA inhibition?
Benzodiazepines
Which medication may accelerate cognitive decline in elderly patients and inhibit platelet aggregation in aging and liver disease?
Benzodiazepines
Which medication can lead to adrenocortical suppression for 4 to 8 hours after an induction dose?
Etomidate
What is the recommended pediatric dosing for midazolam for induction of anesthesia?
1 - 2.5 mg IV
How is diazepam metabolized in the body?
Oxidative N-demethylation
What is the elimination half-time of diazepam in healthy volunteers?
$21 - 37$ hrs.
How does midazolam affect blood pressure and heart rate?
Decrease in BP & increase in HR
What is the commercial preparation of diazepam dissolved in?
Propylene glycol and Sodium benzoate
What is the peak effect onset time for intravenous sedation with midazolam?
$30 - 60$ seconds
What is the plasma concentration at which awakening occurs in children and the elderly when using propofol for induction of anesthesia?
1.0 to 1.5 𝜇/mL
What effect does propofol have on cerebral blood flow?
Decreases cerebral blood flow
What is a potential adverse effect of propofol on the cardiovascular system?
Decreases systemic blood pressure
How does propofol affect hepatic or renal function?
Does not affect hepatic or renal function
What is a potential risk associated with prolonged infusions of propofol?
Propofol Infusion Syndrome
Which adverse event is most commonly reported with propofol?
Pain on injection
What is a potential trigger for allergic reactions to propofol?
Phenyl nucleus
Which organ system does propofol affect?
Intraocular pressure
What is the mechanism of action of etomidate?
Selective modulation of GABAA receptors
What is a characteristic effect of etomidate on ICP (intracranial pressure)?
Decreases ICP
Which drug induces a state of calm or sleep?
Sedative
What is the chemical structure of Propofol?
$2,6$-diisopropyl phenol
What risk is associated with mixing lidocaine and propofol?
Pulmonary embolism
Which propofol alternative has a higher pain on injection?
Ampofol
What is the main concern with Aquavan and fospropofol?
Risk of infection
What is the function of Sedatives?
Induce a state of calm or sleep
What is a potential adverse effect of propofol on the cardiovascular system?
Hypotension
What is the mechanism of action of etomidate?
Selective modulation of GABAA receptors
Which adverse event is most commonly reported with propofol?
Pain on injection
Which organ system does propofol affect?
Intraocular pressure and coagulation
What is a potential trigger for allergic reactions to propofol?
Phenyl nucleus and diisopropyl side chain
What risk is associated with mixing lidocaine and propofol?
Cardiotoxicity
Which medication has minimal detrimental effects when accidentally injected into an artery?
Etomidate
Which medication may accelerate cognitive decline in elderly patients and inhibit platelet aggregation in aging and liver disease?
Midazolam
Which medication has a built-in ceiling effect, preventing it from exceeding the physiologic maximum of GABA inhibition?
Diazepam
Which medication is effective for acute insomnia but may lead to cognitive problems and mortality?
Midazolam
What risk is associated with mixing lidocaine and propofol?
Allergic reaction
What is a characteristic effect of etomidate on ICP (intracranial pressure)?
No effect on ICP
What is the recommended timing for administering midazolam before surgery?
20 minutes before surgery
What is the onset time for intravenous sedation with midazolam?
30 - 60 seconds
How is diazepam metabolized in the body?
Oxidative N-demethylation
What is the elimination half-time of diazepam in healthy volunteers?
$21 - 37$ hours
What is the commercial preparation of diazepam dissolved in?
Organic solvents (propylene glycol, sodium benzoate)
Which medication has a longer elimination half-time than lorazepam but shorter duration of action?
$\text{Diazepam}$
What is the plasma concentration at which awakening occurs in children and the elderly when using propofol for induction of anesthesia?
1.0 to 1.5 𝜇/mL
What is one of the non-hypnotic therapeutic applications of propofol?
Anticonvulsant activity
What effect does propofol have on cerebral blood flow?
Decreases cerebral blood flow
What risk is associated with mixing lidocaine and propofol?
Increased risk of oculocardiac reflex
How does propofol affect hepatic or renal function?
Does not affect hepatic or renal function
What is a potential adverse effect of propofol on the cardiovascular system?
Inhibits sympathetic vasoconstrictor nerve activity
What is the chemical structure of Propofol?
2,6-diisopropyl phenol
Which organ system does propofol affect?
Central Nervous System
What is a potential risk associated with mixing lidocaine and propofol?
Pulmonary embolism
What is the alternative to Propofol that has a higher pain on injection?
Ampofol
What is the function of Anxiolytics?
To reduce anxiety
What is the primary component in Propofol's formulation that supports bacterial growth and increases triglycerides with prolonged infusion?
Soybean oil
What is the primary characteristic of dissociative anesthesia produced by ketamine?
Eyes remain open with slow nystagmic gaze
What is the main limitation of ketamine as a sole anesthetic agent?
Frequency of emergence delirium
What is the structure-activity relationship of ketamine?
Water soluble molecule resembling phencyclidine
Which isomer of ketamine is used for treatment resistant depression?
S(+) ketamine
What type of anesthesia does ketamine produce?
"Dissociative anesthesia"
What risk limits the clinical usefulness of ketamine as a sole anesthetic agent?
Frequency of emergence delirium
Which molecule does ketamine structurally resemble?
Phencyclidine (angel dust)
What characterizes the patient's state during dissociative anesthesia produced by ketamine?
Noncommunicative with open eyes and slow nystagmic gaze
What distinguishes the S(+) isomer of ketamine from the R (-) isomer?
It is used for treatment resistant depression (Spravato)
What distinguishes dissociative anesthesia from other types of anesthesia produced by ketamine?
Evidence on EEG of dissociation between thalamocortical and limbic systems
What is the mechanism of action of ketamine-induced analgesia and dissociative anesthesia?
Binding to N-methyl-D-aspartate receptors and exerting effects at other sites
What is a clinical use of ketamine?
Managing postoperative pain
What effect does chronic administration of ketamine have on enzyme activity?
Enzyme induction and tolerance
What is a potential adverse effect of ketamine on the cardiovascular system?
Causes tissue damage
How does subanesthetic doses of ketamine affect opioid tolerance?
Reduces opioid tolerance
What is a potential approach for preventing emergence delirium caused by ketamine?
The use of benzodiazepines preoperatively
What is a characteristic of ketamine's metabolism by cytochrome P450?
Forms a metabolite that is less potent than ketamine
What is a potential application for ketamine induction of anesthesia?
Burn patients and pediatrics
What is the pharmacokinetic characteristic of ketamine's volume of distribution?
Large volume of distribution due to high lipid solubility
What is a potential effect of subanesthetic doses of ketamine on psychiatric disorders?
Improvement in psychiatric disorders
Which drug is considered the 'Gold Standard' in anesthesia and was introduced in 1934?
Thiopental
What is a key risk factor for dreams and hallucinations occurring up to 24 hours after administration of ketamine?
Age
What is a potential side effect of barbiturates?
Enhanced action of NMBD’s
Which drug is a highly selective alpha-2 adrenergic agonist and is used to calm patients and reduce the hemodynamic response to tracheal intubation?
Dexmedetomidine
What is a use of thiopental in clinical practice?
Induction of anesthesia, increased intracranial pressure, and ischemic injury
What can intra-arterial injection of thiopental cause?
Vasoconstriction, pain, gangrene, and permanent damage
What is a potential allergic reaction that can occur with thiopental due to histamine release?
Anaphylactic or anaphylactoid reactions
What is a notable interaction involving ketamine?
Hypotension with inhaled anesthetics
What do barbiturates potentiate?
Enhanced action of NMBD’s
What is the primary characteristic of dissociative anesthesia produced by ketamine?
Eyes remain open with slow nystagmic gaze
What is the commercial preparation of diazepam dissolved in?
Propylene glycol
What is a notable interaction involving ketamine?
Monoamine oxidase inhibitors (MAOIs)
What do the two optical isomers of ketamine refer to?
$S(+) ketamine & R (-) ketamine$
What is a potential application for ketamine induction of anesthesia?
Pediatric anesthesia
What risk is associated with mixing lidocaine and propofol?
Risk of seizures
What is a characteristic of ketamine's metabolism by cytochrome P450?
It undergoes extensive metabolism by CYP3A4
What distinguishes dissociative anesthesia from other types of anesthesia produced by ketamine?
Patient experiences amnesia and intense analgesia
What is the structure-activity relationship of ketamine?
It structurally resembles phencyclidine (angel dust)
Which medication has minimal detrimental effects when accidentally injected into an artery?
Ketamine
Which of the following is a risk factor for the occurrence of dreams and hallucinations after administration of ketamine?
Age
What is a key interaction involving thiopental?
Enhanced action of non-depolarizing neuromuscular blocking drugs (NMBD’s)
What characterizes the effect of barbiturates on GABAA channel activity?
Potentiation
What is a clinical use of dexmedetomidine?
Reducing plasma catecholamine concentration during anesthesia
What are the dose requirements for thiopental based on?
Patient characteristics
What is a potential side effect of barbiturates on ventilatory centers?
$CO_2$ retention
What can intra-arterial injection of thiopental cause?
Vasoconstriction, pain, and permanent damage
What is a notable characteristic of dexmedetomidine compared to clonidine?
More rapid onset of action
What is a potential adverse effect associated with allergic reactions to thiopental?
Hypotension and bradycardia
What is a potential side effect of barbiturates due to enzyme induction?
Reduced metabolism of various drugs
What is the mechanism of action of ketamine-induced analgesia and dissociative anesthesia?
Inhibition of NMDA receptors
What is a potential use of ketamine induction of anesthesia?
Treating psychiatric disorders
How does ketamine affect the central nervous system?
Decreases presynaptic release of glutamate
What is a notable pharmacokinetic property of ketamine?
Rapid onset of action
What is a potential adverse effect of ketamine on the cardiovascular system?
Increases heart rate
Study Notes
Intravenous Anesthetics: Propofol and Etomidate
- Propofol has effects on organ systems, including intraocular pressure and coagulation
- Propofol's oil-in-water emulsion formulation is associated with side effects such as bradycardia and risk of infection
- Allergic reactions to propofol can be triggered by allergenic components like phenyl nucleus and diisopropyl side chain
- Propofol has effects on organ systems, including lactic acidosis and proconvulsant activity
- Propofol has antioxidant properties and can inhibit lipid peroxidation
- Pain on injection is the most commonly reported adverse event with propofol
- Etomidate is a carboxylated imidazole-containing compound with altered pharyngeal function and a risk of aspiration
- Etomidate's mechanism of action involves selective modulation of GABAA receptors
- Etomidate is rapidly metabolized by hydrolysis and has a large tissue uptake
- Etomidate is an alternative to propofol or barbiturates for IV induction, with an onset from arm to brain circulation
- Etomidate has potent direct cerebral vasoconstrictor effects and decreases ICP
- Cardiovascular stability is characteristic of induction with etomidate, with minimal changes in HR, SV, and CO.
Propofol: Clinical Uses and Effects
- Propofol is a selective modulator of GABAA receptors with evidence of potentiation at glycine receptors.
- The clearance of propofol from plasma exceeds hepatic blood flow, with first-pass uptake into lung and hepatic oxidative metabolism.
- It is widely used for induction of anesthesia in children and the elderly, with awakening occurring at plasma concentrations of 1.0 to 1.5 𝜇/mL.
- Propofol is used for intravenous sedation, mechanical ventilation, and cardiac surgery to modulate postoperative hemodynamic responses.
- It is also employed for maintenance of anesthesia and has non-hypnotic therapeutic applications such as antiemetic effects, anticonvulsant activity, and attenuation of bronchoconstriction.
- Propofol interacts with opioids, affecting their plasma concentration, distribution clearance, and elimination clearance.
- Propofol decreases cerebral metabolic rate for oxygen, cerebral blood flow, intracranial pressure, and does not affect cerebral autoregulation.
- It decreases systemic blood pressure, inhibits sympathetic vasoconstrictor nerve activity, and has a negative inotropic effect on the cardiovascular system.
- Profound bradycardia and asystole have been reported in healthy adult patients even with anticholinergic prophylaxis, and it can increase the risk of oculocardiac reflex during pediatric strabismus surgery repair.
- Propofol does not affect hepatic or renal function, but it can cause dose-dependent depression of ventilation and may lead to Propofol Infusion Syndrome with prolonged infusions.
- It can also potentiate respiratory depression when used with opioids and decrease the ventilatory response to arterial hypoxemia.
- Formulations with cyclodextrins can have significant effects on wheezing and respiratory resistance after tracheal intubation.
Anesthesia Drugs: Key Facts and Clinical Applications
- Dreams and hallucinations can occur up to 24 hours after administration of ketamine, with an incidence of 5 to 30% and risk factors including age, gender, dose, and personality problems.
- Ketamine interactions include hypotension with inhaled anesthetics, enhanced action of NMBD’s, and interference with heart preconditioning and succinylcholine recovery.
- Thiopental, introduced in 1934, revolutionized anesthesia practice and is considered the "Gold Standard" in anesthesia.
- Barbiturates, derived from barbituric acid, have different substitutions determining their properties, including oxygen or sulfur in different positions affecting lipid solubility and potency.
- Barbiturates potentiate GABAA channel activity and have been replaced by benzodiazepines for pre-op medication and treating seizures.
- Barbiturates have rapid onset and awakening due to redistribution, prolonged context-sensitive half-time, and hangover-type CNS effects.
- Thiopental is used for increased intracranial pressure, ischemic injury, and induction of anesthesia, with dose requirements varying with patient characteristics.
- Side effects of barbiturates include changes in somatosensory evoked potentials, dose-dependent depression of ventilatory centers, and enzyme induction leading to accelerated metabolism of various drugs.
- Intra-arterial injection of thiopental can cause vasoconstriction, pain, gangrene, and permanent damage.
- Allergic reactions, including anaphylactic and anaphylactoid, can occur with thiopental due to histamine release.
- Dexmedetomidine is a highly selective alpha-2 adrenergic agonist, with a shorter duration of action compared to clonidine and is used to calm patients and reduce the hemodynamic response to tracheal intubation.
- Clinical use of dexmedetomidine includes attenuating the hemodynamic response to tracheal intubation, decreasing plasma catecholamine concentration during anesthesia, reducing perioperative requirements of opioids and inhaled anesthetics, and treating post-op shivering.
Ketamine: Mechanism, Pharmacokinetics, Clinical Uses, and Side Effects
- Esketamine is widely used in Europe and has more intense analgesia, faster metabolism, less salivation, and lower incidence of emergence reactions.
- Both isomers of ketamine inhibit reuptake of catecholamines back into postganglionic sympathetic nerve endings.
- Mechanism of action of ketamine-induced analgesia and dissociative anesthesia is unknown, but it binds to N-methyl-D-aspartate receptors and exerts effects at other sites including opioid receptors, monoaminergic receptors, and muscarinic receptors.
- Ketamine inhibits neutrophil production of inflammatory mediators, improves blood flow, and inhibits cytokines in blood, contributing to its analgesic effect.
- Ketamine is a member of the glutamate receptor family, inhibits activation of NMDA receptors by glutamate, and decreases presynaptic release of glutamate.
- Ketamine has a rapid onset of action, relatively short duration of action, and high lipid solubility. It is not significantly bound to plasma proteins and has high hepatic clearance and large volume of distribution.
- Ketamine undergoes extensive metabolism by cytochrome P450, forming the norketamine metabolite, which is 1/5 to 1/3 as potent as ketamine. Chronic administration causes enzyme induction and tolerance.
- Ketamine is used for analgesia, inducing anesthesia, managing postoperative pain, and providing analgesia during labor without neonatal depression.
- Ketamine induction of anesthesia is safe, does not produce pain or irritation on injection, and has useful applications in burn patients, pediatrics, and hypovolemic patients.
- Subanesthetic doses of ketamine reduce the likelihood of opioid tolerance, improve analgesia, and have shown improvement in psychiatric disorders and restless leg syndrome.
- Ketamine has various effects on the central nervous system, cardiovascular system, ventilation and airway, and can cause tissue damage, allergic reactions, and emergence delirium.
- Prevention of emergence delirium can be achieved through the use of benzodiazepines preoperatively, as emergence delirium may result in visual, auditory, proprioceptive, and confusional illusions.
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