Podcast
Questions and Answers
Which of the following is a characteristic of dissociative anesthesia produced by ketamine?
Which of the following is a characteristic of dissociative anesthesia produced by ketamine?
- The patient is amnesic (correct)
- The patient's eyes remain closed
- The patient is communicative and responsive
- The patient experiences intense analgesia
What advantage does ketamine have over propofol and etomidate?
What advantage does ketamine have over propofol and etomidate?
- It is not a drug with abuse potential
- It does not cause emergence delirium
- It produces profound analgesia at subanesthetic doses
- It does not require a lipid emulsion vehicle for dissolution (correct)
What limits the clinical usefulness of ketamine as a sole agent?
What limits the clinical usefulness of ketamine as a sole agent?
- The need for a lipid emulsion vehicle for dissolution
- The lack of analgesic properties
- The frequency of emergence delirium (correct)
- The potential for abuse
Which system in the brain shows evidence of dissociation in dissociative anesthesia produced by ketamine?
Which system in the brain shows evidence of dissociation in dissociative anesthesia produced by ketamine?
What is a characteristic of the patient's eyes during dissociative anesthesia produced by ketamine?
What is a characteristic of the patient's eyes during dissociative anesthesia produced by ketamine?
What is the patient's level of wakefulness during dissociative anesthesia produced by ketamine?
What is the patient's level of wakefulness during dissociative anesthesia produced by ketamine?
What is a common occurrence during dissociative anesthesia produced by ketamine?
What is a common occurrence during dissociative anesthesia produced by ketamine?
What is the patient's level of analgesia during dissociative anesthesia produced by ketamine?
What is the patient's level of analgesia during dissociative anesthesia produced by ketamine?
What advantage does ketamine have over propofol and etomidate?
What advantage does ketamine have over propofol and etomidate?
What limits the clinical usefulness of ketamine as a sole agent?
What limits the clinical usefulness of ketamine as a sole agent?
What precaution should be taken with ketamine due to its abuse potential?
What precaution should be taken with ketamine due to its abuse potential?
Which of the following is true about ketamine?
Which of the following is true about ketamine?
What is the designation for the left-handed optical isomer of ketamine?
What is the designation for the left-handed optical isomer of ketamine?
Which form of ketamine is clinically available for treatment of therapy-resistant depression?
Which form of ketamine is clinically available for treatment of therapy-resistant depression?
In Europe, esketamine is widely used for what purposes?
In Europe, esketamine is widely used for what purposes?
When studied separately, which isomer of ketamine produces more intense analgesia?
When studied separately, which isomer of ketamine produces more intense analgesia?
Which isomer of ketamine has a lower incidence of emergence reactions?
Which isomer of ketamine has a lower incidence of emergence reactions?
What is the analgesic potency of esketamine compared to racemic ketamine?
What is the analgesic potency of esketamine compared to racemic ketamine?
Which isomer of ketamine induces less fatigue and cognitive impairment at equianalgesic small doses?
Which isomer of ketamine induces less fatigue and cognitive impairment at equianalgesic small doses?
What effect does both isomers of ketamine have on the uptake of catecholamines back into postganglionic sympathetic nerve endings?
What effect does both isomers of ketamine have on the uptake of catecholamines back into postganglionic sympathetic nerve endings?
What is the preservative used for ketamine?
What is the preservative used for ketamine?
What is the mechanism of action of ketamine-induced analgesia and dissociative anesthesia?
What is the mechanism of action of ketamine-induced analgesia and dissociative anesthesia?
What is the effect of ketamine on GABAA receptors?
What is the effect of ketamine on GABAA receptors?
What is the role of the innate repair receptor in mediating ketamine's effects on neuropathic pain?
What is the role of the innate repair receptor in mediating ketamine's effects on neuropathic pain?
What is the effect of ketamine on the analgesic relief of acute pain?
What is the effect of ketamine on the analgesic relief of acute pain?
What is the effect of ketamine on cytokines in blood?
What is the effect of ketamine on cytokines in blood?
What is the effect of ketamine on neutrophil production of inflammatory mediators?
What is the effect of ketamine on neutrophil production of inflammatory mediators?
Which receptors does ketamine bind noncompetitively to?
Which receptors does ketamine bind noncompetitively to?
Which receptors does ketamine exert effects at?
Which receptors does ketamine exert effects at?
What is the designation for the left-handed optical isomer of ketamine?
What is the designation for the left-handed optical isomer of ketamine?
What is the effect of ketamine on wakefulness during dissociative anesthesia?
What is the effect of ketamine on wakefulness during dissociative anesthesia?
Which receptors does ketamine primarily interact with to inhibit the activation of NMDA receptors?
Which receptors does ketamine primarily interact with to inhibit the activation of NMDA receptors?
What effect does ketamine have on sodium channels?
What effect does ketamine have on sodium channels?
Which type of nicotinic acetylcholine receptors does ketamine interact with?
Which type of nicotinic acetylcholine receptors does ketamine interact with?
Which of the following is true about the pharmacokinetics of ketamine?
Which of the following is true about the pharmacokinetics of ketamine?
Where does ketamine initially distribute after administration?
Where does ketamine initially distribute after administration?
What is the elimination half-life of ketamine?
What is the elimination half-life of ketamine?
Which enzyme is responsible for the demethylation of ketamine to form norketamine and hydroxynorketamine?
Which enzyme is responsible for the demethylation of ketamine to form norketamine and hydroxynorketamine?
What is the percentage of a dose of ketamine that can be recovered from urine as unchanged drug after intravenous administration?
What is the percentage of a dose of ketamine that can be recovered from urine as unchanged drug after intravenous administration?
What effect does chronic administration of ketamine have on the metabolism of the drug?
What effect does chronic administration of ketamine have on the metabolism of the drug?
Which drug is often recommended to decrease the likelihood of coughing and laryngospasm due to ketamine-induced salivary secretions?
Which drug is often recommended to decrease the likelihood of coughing and laryngospasm due to ketamine-induced salivary secretions?
At what doses does ketamine produce prompt induction of anesthesia when administered intravenously?
At what doses does ketamine produce prompt induction of anesthesia when administered intravenously?
What is the primary clinical effect of ketamine at subanesthetic doses?
What is the primary clinical effect of ketamine at subanesthetic doses?
Which system is responsible for the interpretation of painful signals?
Which system is responsible for the interpretation of painful signals?
What is the role of NMDA receptors in pain processing?
What is the role of NMDA receptors in pain processing?
What is the effect of ketamine on neonatal neurobehavioral scores?
What is the effect of ketamine on neonatal neurobehavioral scores?
Which of the following is a potential advantage of using ketamine as an analgesic adjuvant in patients with preexisting chronic pain syndromes who require surgery?
Which of the following is a potential advantage of using ketamine as an analgesic adjuvant in patients with preexisting chronic pain syndromes who require surgery?
What is the most likely reason for the limited value of neuraxial ketamine in producing analgesia?
What is the most likely reason for the limited value of neuraxial ketamine in producing analgesia?
What is the most likely reason for the additive or synergistic effect of ketamine when combined with other epidural analgesics?
What is the most likely reason for the additive or synergistic effect of ketamine when combined with other epidural analgesics?
Which receptors are responsible for the analgesic effects of ketamine?
Which receptors are responsible for the analgesic effects of ketamine?
What is the primary mechanism of action of ketamine as an analgesic?
What is the primary mechanism of action of ketamine as an analgesic?
What is the role of NMDA receptors in pain processing?
What is the role of NMDA receptors in pain processing?
What is the effect of ketamine on sodium channels?
What is the effect of ketamine on sodium channels?
What is the most likely reason for the limited value of neuraxial ketamine in producing analgesia?
What is the most likely reason for the limited value of neuraxial ketamine in producing analgesia?
What is the effect of chronic administration of ketamine on the metabolism of the drug?
What is the effect of chronic administration of ketamine on the metabolism of the drug?
What is the most likely reason for the additive or synergistic effect of ketamine when combined with other epidural analgesics?
What is the most likely reason for the additive or synergistic effect of ketamine when combined with other epidural analgesics?
Which of the following is true about the analgesic effects of ketamine?
Which of the following is true about the analgesic effects of ketamine?
What is the most likely reason for the lower potential for abuse or addiction associated with hydroxynorketamine?
What is the most likely reason for the lower potential for abuse or addiction associated with hydroxynorketamine?
What is the most likely reason for the limited value of neuraxial ketamine for producing analgesia?
What is the most likely reason for the limited value of neuraxial ketamine for producing analgesia?
What is the most likely reason for the additive or synergistic effect of ketamine when combined with other epidural analgesics?
What is the most likely reason for the additive or synergistic effect of ketamine when combined with other epidural analgesics?
What is a characteristic of dissociative anesthesia produced by ketamine?
What is a characteristic of dissociative anesthesia produced by ketamine?
What is the effect of ketamine on GABAA receptors?
What is the effect of ketamine on GABAA receptors?
What is the effect of ketamine on wakefulness during dissociative anesthesia?
What is the effect of ketamine on wakefulness during dissociative anesthesia?
What is the elimination half-life of ketamine?
What is the elimination half-life of ketamine?
Which route of administration of ketamine does not produce pain or venous irritation?
Which route of administration of ketamine does not produce pain or venous irritation?
How long does it take for consciousness to be lost after intravenous administration of ketamine?
How long does it take for consciousness to be lost after intravenous administration of ketamine?
What is the usual duration of unconsciousness after an injected induction dose of ketamine?
What is the usual duration of unconsciousness after an injected induction dose of ketamine?
What is the typical duration of amnesia after recovery of consciousness from ketamine?
What is the typical duration of amnesia after recovery of consciousness from ketamine?
What is a potential advantage of using ketamine in burn patients undergoing dressing changes and skin grafting procedures?
What is a potential advantage of using ketamine in burn patients undergoing dressing changes and skin grafting procedures?
What is the primary clinical effect of ketamine at subanesthetic doses?
What is the primary clinical effect of ketamine at subanesthetic doses?
What is the cardiovascular effect of ketamine in acutely hypovolemic patients?
What is the cardiovascular effect of ketamine in acutely hypovolemic patients?
What is the typical emergence time after repeated intravenous injections or continuous infusion of ketamine?
What is the typical emergence time after repeated intravenous injections or continuous infusion of ketamine?
What is the effect of chronic administration of ketamine on tolerance?
What is the effect of chronic administration of ketamine on tolerance?
In which patient population has ketamine been used as an intramuscular induction drug?
In which patient population has ketamine been used as an intramuscular induction drug?
Which of the following is a consideration when administering ketamine to patients with coronary artery disease?
Which of the following is a consideration when administering ketamine to patients with coronary artery disease?
What is the recommended induction of anesthesia in patients with coronary artery disease?
What is the recommended induction of anesthesia in patients with coronary artery disease?
What is the potential benefit of combining subanesthetic doses of ketamine with propofol for total IV anesthesia?
What is the potential benefit of combining subanesthetic doses of ketamine with propofol for total IV anesthesia?
Why is ketamine considered a potentially useful drug for rapid IV induction of anesthesia in patients with asthma?
Why is ketamine considered a potentially useful drug for rapid IV induction of anesthesia in patients with asthma?
What precaution should be taken with ketamine in patients with systemic or pulmonary hypertension or increased ICP?
What precaution should be taken with ketamine in patients with systemic or pulmonary hypertension or increased ICP?
What is a potential undesirable effect of ketamine administration during eye operations or examinations?
What is a potential undesirable effect of ketamine administration during eye operations or examinations?
Is ketamine safe to administer to patients with malignant hyperthermia?
Is ketamine safe to administer to patients with malignant hyperthermia?
What is a potential use of ketamine in pediatric cardiac catheterization?
What is a potential use of ketamine in pediatric cardiac catheterization?
Should ketamine be used cautiously or avoided in patients with systemic or pulmonary hypertension?
Should ketamine be used cautiously or avoided in patients with systemic or pulmonary hypertension?
What effect does ketamine have on the interpretation of catheterization data in patients with coronary artery disease?
What effect does ketamine have on the interpretation of catheterization data in patients with coronary artery disease?
Which receptor is believed to be involved in the mechanism of opioid-induced tolerance?
Which receptor is believed to be involved in the mechanism of opioid-induced tolerance?
What is the effect of subanesthetic doses of ketamine on opioid tolerance?
What is the effect of subanesthetic doses of ketamine on opioid tolerance?
In which psychiatric disorder has ketamine been shown to improve the postoperative depressive state?
In which psychiatric disorder has ketamine been shown to improve the postoperative depressive state?
What is the FDA-approved use of intranasal esketamine?
What is the FDA-approved use of intranasal esketamine?
What is the possible mechanism by which ketamine improves restless leg syndrome?
What is the possible mechanism by which ketamine improves restless leg syndrome?
What are the NMDA receptors thought to be involved in the pathophysiology of?
What are the NMDA receptors thought to be involved in the pathophysiology of?
What is the effect of intermittent treatment with low-dose ketamine in patients with obsessive compulsive disorder?
What is the effect of intermittent treatment with low-dose ketamine in patients with obsessive compulsive disorder?
What is the effect of ketamine on the analgesic relief of acute pain?
What is the effect of ketamine on the analgesic relief of acute pain?
Which system in the body does ketamine potentially inhibit to improve restless leg syndrome?
Which system in the body does ketamine potentially inhibit to improve restless leg syndrome?
What is the FDA-approved use of intranasal esketamine in conjunction with?
What is the FDA-approved use of intranasal esketamine in conjunction with?
Which of the following is a unique characteristic of ketamine among injected anesthetics?
Which of the following is a unique characteristic of ketamine among injected anesthetics?
What is the effect of ketamine on intracranial pressure in mechanically ventilated animals with increased ICP?
What is the effect of ketamine on intracranial pressure in mechanically ventilated animals with increased ICP?
In patients requiring craniotomy for brain tumor or cerebral aneurysm resection, what effect does administration of ketamine have on middle cerebral artery blood flow velocity?
In patients requiring craniotomy for brain tumor or cerebral aneurysm resection, what effect does administration of ketamine have on middle cerebral artery blood flow velocity?
What effect does ketamine have on intracranial pressure in patients with traumatic brain injury?
What effect does ketamine have on intracranial pressure in patients with traumatic brain injury?
What is the primary reason why ketamine is considered contraindicated in patients with increased intracranial pressure (ICP)?
What is the primary reason why ketamine is considered contraindicated in patients with increased intracranial pressure (ICP)?
What effect does ketamine have on anterior fontanelle pressure in mechanically ventilated preterm neonates?
What effect does ketamine have on anterior fontanelle pressure in mechanically ventilated preterm neonates?
What effect does ketamine have on cerebral metabolic rate of oxygen (CMRO2)?
What effect does ketamine have on cerebral metabolic rate of oxygen (CMRO2)?
What is the effect of ketamine on cerebral blood flow in the presence of normocapnia?
What is the effect of ketamine on cerebral blood flow in the presence of normocapnia?
What is the primary reason why patients with intracranial pathology are considered vulnerable to sustained increases in ICP after administration of ketamine?
What is the primary reason why patients with intracranial pathology are considered vulnerable to sustained increases in ICP after administration of ketamine?
What is the primary effect of ketamine at subanesthetic doses?
What is the primary effect of ketamine at subanesthetic doses?
Which of the following is true about ketamine's effect on the EEG?
Which of the following is true about ketamine's effect on the EEG?
What is the effect of ketamine on somatosensory evoked potentials?
What is the effect of ketamine on somatosensory evoked potentials?
What is the effect of ketamine on auditory and visual evoked responses?
What is the effect of ketamine on auditory and visual evoked responses?
Which of the following is a cardiovascular effect of ketamine?
Which of the following is a cardiovascular effect of ketamine?
What is the typical pattern of systemic blood pressure after IV injection of ketamine?
What is the typical pattern of systemic blood pressure after IV injection of ketamine?
Which of the following can prevent or blunt the cardiovascular-stimulating effects of ketamine?
Which of the following can prevent or blunt the cardiovascular-stimulating effects of ketamine?
Which anesthetic is associated with a higher survival rate in shocked animals compared to halothane?
Which anesthetic is associated with a higher survival rate in shocked animals compared to halothane?
What is the effect of ketamine administration on arterial lactate concentrations in animals with lower systemic blood pressures?
What is the effect of ketamine administration on arterial lactate concentrations in animals with lower systemic blood pressures?
What is the potential consequence of ketamine-induced vasoconstriction on tissue perfusion?
What is the potential consequence of ketamine-induced vasoconstriction on tissue perfusion?
Which of the following is the most important mechanism for the cardiovascular stimulation caused by ketamine?
Which of the following is the most important mechanism for the cardiovascular stimulation caused by ketamine?
What effect does ketamine have on epinephrine-induced cardiac dysrhythmias?
What effect does ketamine have on epinephrine-induced cardiac dysrhythmias?
What is the effect of inhaled anesthetics, ganglionic blockade, β-blockade, cervical epidural anesthesia, and spinal cord transection on ketamine-induced increases in systemic blood pressure and heart rate?
What is the effect of inhaled anesthetics, ganglionic blockade, β-blockade, cervical epidural anesthesia, and spinal cord transection on ketamine-induced increases in systemic blood pressure and heart rate?
Which of the following mechanisms has been suggested as a possible explanation for how ketamine produces airway relaxation?
Which of the following mechanisms has been suggested as a possible explanation for how ketamine produces airway relaxation?
What is a potential adverse effect associated with repeated use of ketamine in high doses?
What is a potential adverse effect associated with repeated use of ketamine in high doses?
Which of the following is a possible effect of ketamine on the liver?
Which of the following is a possible effect of ketamine on the liver?
Which of the following statements about ketamine's effect on ventilation is most accurate?
Which of the following statements about ketamine's effect on ventilation is most accurate?
What effect does ketamine have on upper airway reflexes and muscle tone?
What effect does ketamine have on upper airway reflexes and muscle tone?
What is the recommended precaution when using ketamine to prevent aspiration?
What is the recommended precaution when using ketamine to prevent aspiration?
Which receptors does ketamine primarily interact with to inhibit the activation of NMDA receptors?
Which receptors does ketamine primarily interact with to inhibit the activation of NMDA receptors?
What is the most likely reason for the limited value of neuraxial ketamine in producing analgesia?
What is the most likely reason for the limited value of neuraxial ketamine in producing analgesia?
What is the effect of ketamine on upper airway reflexes and muscle tone?
What is the effect of ketamine on upper airway reflexes and muscle tone?
Which of the following factors is NOT associated with an increased incidence of emergence delirium after administration of ketamine?
Which of the following factors is NOT associated with an increased incidence of emergence delirium after administration of ketamine?
What is the most effective drug in preventing emergence delirium after administration of ketamine?
What is the most effective drug in preventing emergence delirium after administration of ketamine?
What is the effect of including atropine in the preoperative medication before administration of ketamine?
What is the effect of including atropine in the preoperative medication before administration of ketamine?
Which of the following is a potential drug interaction with ketamine that may result in hypotension?
Which of the following is a potential drug interaction with ketamine that may result in hypotension?
What is the potential effect of ketamine on the duration of apnea after administration of succinylcholine?
What is the potential effect of ketamine on the duration of apnea after administration of succinylcholine?
Which of the following is a potential effect of ketamine on the cardiovascular system?
Which of the following is a potential effect of ketamine on the cardiovascular system?
Which type of ketamine blocks the cardioprotective effects of ischemic preconditioning in an animal model?
Which type of ketamine blocks the cardioprotective effects of ischemic preconditioning in an animal model?
Which type of ketamine does not block the cardioprotective effects of preconditioning or alter myocardial infarct size in an animal model?
Which type of ketamine does not block the cardioprotective effects of preconditioning or alter myocardial infarct size in an animal model?
Which drugs should be used with caution in patients at risk for myocardial infarction during the perioperative period?
Which drugs should be used with caution in patients at risk for myocardial infarction during the perioperative period?
Which of the following is a common ingredient in over-the-counter cough suppressants?
Which of the following is a common ingredient in over-the-counter cough suppressants?
What is the potency of dextromethorphan as an antitussive compared to codeine?
What is the potency of dextromethorphan as an antitussive compared to codeine?
Which of the following is a symptom of intentional excessive intake of dextromethorphan?
Which of the following is a symptom of intentional excessive intake of dextromethorphan?
Which drug has a longer elimination half-time, dexmedetomidine or clonidine?
Which drug has a longer elimination half-time, dexmedetomidine or clonidine?
What is the primary route of excretion for the metabolites of dexmedetomidine?
What is the primary route of excretion for the metabolites of dexmedetomidine?
What effect might dexmedetomidine have on plasma concentrations of opioids administered during anesthesia?
What effect might dexmedetomidine have on plasma concentrations of opioids administered during anesthesia?
Which receptor does dexmedetomidine primarily act on?
Which receptor does dexmedetomidine primarily act on?
What is the pharmacologically active component of medetomidine?
What is the pharmacologically active component of medetomidine?
What is the role of atipamezole in relation to dexmedetomidine?
What is the role of atipamezole in relation to dexmedetomidine?
Which receptor does dexmedetomidine primarily act on?
Which receptor does dexmedetomidine primarily act on?
What is the main effect of dexmedetomidine on the sympathetic nervous system?
What is the main effect of dexmedetomidine on the sympathetic nervous system?
Which drug is a specific and selective α2-receptor antagonist that reverses the sedative effects of dexmedetomidine?
Which drug is a specific and selective α2-receptor antagonist that reverses the sedative effects of dexmedetomidine?
Which of the following statements about the elimination half-time of dexmedetomidine is true?
Which of the following statements about the elimination half-time of dexmedetomidine is true?
What is the primary route of excretion for the metabolites of dexmedetomidine?
What is the primary route of excretion for the metabolites of dexmedetomidine?
What effect does dexmedetomidine have on cytochrome P450 enzyme systems?
What effect does dexmedetomidine have on cytochrome P450 enzyme systems?
Which of the following is a clinical use of dexmedetomidine?
Which of the following is a clinical use of dexmedetomidine?
What effect does dexmedetomidine have on MAC for volatile anesthetics in animals?
What effect does dexmedetomidine have on MAC for volatile anesthetics in animals?
What effect does dexmedetomidine have on the range of temperatures triggering thermoregulatory defenses?
What effect does dexmedetomidine have on the range of temperatures triggering thermoregulatory defenses?
Which of the following is a clinical use of dexmedetomidine?
Which of the following is a clinical use of dexmedetomidine?
What effect does dexmedetomidine have on MAC for volatile anesthetics in animals?
What effect does dexmedetomidine have on MAC for volatile anesthetics in animals?
What is a potential anesthetic technique for patients with a difficult upper airway?
What is a potential anesthetic technique for patients with a difficult upper airway?
Which of the following is a clinical use of dexmedetomidine?
Which of the following is a clinical use of dexmedetomidine?
What effect does dexmedetomidine have on MAC for volatile anesthetics in animals?
What effect does dexmedetomidine have on MAC for volatile anesthetics in animals?
What is the effect of adding dexmedetomidine to lidocaine for IV regional anesthesia?
What is the effect of adding dexmedetomidine to lidocaine for IV regional anesthesia?
Which of the following statements about dexmedetomidine is true?
Which of the following statements about dexmedetomidine is true?
What effect does dexmedetomidine have on the control of breathing?
What effect does dexmedetomidine have on the control of breathing?
What is a potential life-threatening effect of dexmedetomidine?
What is a potential life-threatening effect of dexmedetomidine?
Which of the following is a potential side effect of dexmedetomidine?
Which of the following is a potential side effect of dexmedetomidine?
What effect does dexmedetomidine have on the control of breathing?
What effect does dexmedetomidine have on the control of breathing?
What is a potential use of clonidine and dexmedetomidine in the ICU?
What is a potential use of clonidine and dexmedetomidine in the ICU?
Study Notes
Ketamine Characteristics and Anesthesia
- Dissociative anesthesia causes a trance-like state where the patient is awake but unaware, leading to detachment from the environment.
- Ketamine provides advantages over propofol and etomidate, such as analgesic properties and minimal respiratory depression.
- Limited clinical usefulness as a sole agent primarily due to potential emergence reactions and possible dissociative effects.
Brain Systems and Eye Characteristics
- The limbic system shows evidence of dissociation during ketamine-induced anesthesia.
- Patient's eyes are often open during dissociative anesthesia, with a characteristic gaze.
- Patients exhibit variable levels of wakefulness, potentially remaining responsive to commands despite not fully alert.
- Common occurrences include hallucinations or vivid dreams during recovery.
Analgesia and Inefficacy
- Patients experience significant analgesia, although ketamine is not always sufficient on its own for complete pain management.
- Potential for ketamine abuse necessitates careful monitoring and control in clinical settings.
Isomers and Clinical Applications
- Esketamine is the left-handed optical isomer of ketamine.
- Esketamine is clinically available for treating therapy-resistant depression, showing effectiveness for acute, severe depression.
- The R-ketamine isomer may produce more intense analgesia with fewer emergence reactions.
Pharmacological Effects and Mechanisms
- Ketamine binds noncompetitively to NMDA receptors, inhibiting their activation, and also interacts with nicotinic acetylcholine receptors.
- It affects sodium channels, potentially contributing to its analgesic effect.
- Mechanism includes modulation of GABAA receptors, enhancing inhibitory neurotransmission.
Metabolism and Administration
- Ketamine distributes rapidly post-administration, primarily in the brain and liver.
- Elimination half-life typically ranges from 2 to 3 hours; metabolites include norketamine and hydroxynorketamine.
- Up to 30% of a ketamine dose can be excreted unchanged in urine after intravenous administration.
Clinical Uses and Considerations
- Ketamine can be beneficial in patients with chronic pain syndromes, enhancing analgesia when combined with other medications.
- It is useful in emergency settings, especially for quick induction due to rapid onset and minimal respiratory effects.
- Considerations for use include caution in patients with coronary artery disease, hypertension, or increased intracranial pressure.
Observations and Side Effects
- Administration can lead to altered neurobehavioral scores in neonates and possible psychological effects.
- In pediatric cardiac catheterization, ketamine offers sedation with improved tolerance and minimal cardiovascular instability.
- Chronic use may lead to tolerance, necessitating adjustments in dosage.
Unique Properties and Emergency Management
- Ketamine's unique quality lies in its ability to provide analgesia and dissociative effects without significant respiratory depression.
- It may increase intracranial pressure, posing risks in patients with existing elevated levels.
- Recommended as a safe option for rapid induction in asthmatic patients due to bronchodilator effects.
FDA Approvals and Recent Studies
- Intranasal esketamine is approved for adjunctive treatment in major depressive disorder.
- Low-dose intermittent ketamine treatments show promise in managing obsessive-compulsive disorder.
Effects on Inflammation and Pain Processing
- Ketamine may inhibit the release of inflammatory mediators from neutrophils and modulate cytokine levels during acute pain management.
- NMDA receptors are critically involved in pain processing, with ketamine reducing their activation aiding in pain relief.
Overall Implications
- Ketamine is an important anesthetic with unique properties, useful in various clinical settings, including emergency medicine, pain management, and psychiatric treatment, while requiring careful consideration of dosing and patient status.
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Description
Test your knowledge on non-γ-Aminobutyric Acid sedatives and hypnotics with this quiz. Learn about the pharmacological properties and effects of ketamine, a phencyclidine derivative that produces dissociative anesthesia.
