Induction Agents - Barbiturates Flashcards
What is the typical IV induction dose of thiopental in adults?
3–5 mg/kg
This dosage is standard for inducing anesthesia in adult patients.
What is the onset time of action for thiopental when administered IV?
30–60 seconds
This rapid onset is critical for induction of anesthesia.
How long do the clinical effects of a single IV dose of thiopental typically last?
5–10 minutes
The short duration is due to rapid redistribution.
Thiopental’s primary mechanism of action is:
Enhancement of GABA-A receptor activity
This leads to central nervous system depression.
Which of the following is a key side effect of thiopental?
Laryngospasm
This side effect can complicate airway management.
Which patient condition is contraindicated for thiopental use?
Porphyria
Thiopental can trigger acute attacks in affected patients.
Thiopental is particularly useful in:
Induction in patients with increased intracranial pressure, neuroprotective, decreases CBF and CBV
Its properties make it suitable for neurosurgical procedures.
Is Thiopental a barbiturate used for induction of anesthesia?
Yes
It is commonly utilized in anesthetic practice.
Does thiopental provide good muscle relaxation and analgesia?
No
It lacks analgesic properties.
Does Thiopental cause dose-dependent respiratory and cardiovascular depression?
Yes
Monitoring is essential during administration.
Is Thiopental contraindicated in patients with acute intermittent porphyria?
Yes
This is due to its potential to worsen porphyrin metabolism.
Do the effects of thiopental wear off quickly due to rapid metabolism?
No
Initial recovery is primarily due to redistribution.
Can Thiopental be used for seizure control?
Yes
It is effective in managing certain seizure types.
Does Thiopental produce an increase in intracranial pressure?
No
It actually helps to decrease intracranial pressure.
What is the induction dose of thiopental for adults?
Typically 3–5 mg/kg IV
This is the standard dosing for inducing anesthesia.
How quickly does thiopental take effect after IV administration?
30–60 seconds
This rapid effect is crucial for anesthesia induction.
Why does the clinical effect of thiopental wear off after just a few minutes?
Because of redistribution from the brain to peripheral tissues
This pharmacokinetic property leads to quick recovery.
What is the mechanism of action of thiopental?
Enhancement of GABA-A receptor activity leading to CNS depression, also depresses reticular activation system (RAS)
This results in sedation and loss of consciousness.
Name two common side effects of thiopental.
Respiratory depression, hypotension, laryngospasm
These side effects require careful monitoring.
In what situation is thiopental especially useful due to its cerebral protective effects?
In patients with elevated intracranial pressure or during neurosurgery
Its neuroprotective properties make it favorable in these scenarios.
Why is thiopental contraindicated in porphyria?
It induces hepatic enzymes that worsen porphyrin metabolism, triggering acute attacks
This can lead to serious complications.
Does thiopental provide analgesia?
No, it does not have analgesic properties
It is primarily a sedative agent.
What property of thiopental makes it suitable for rapid sequence induction?
Rapid onset and short duration of action
These characteristics are ideal for emergency scenarios.
What is the typical IV induction dose of methohexital in adults?
50-120 mg
This dosage is used for induction in various procedures.
What is the usual onset of action for methohexital after IV administration?
10–30 seconds
This rapid onset is beneficial for procedural sedation.
What is the typical duration of action for a single IV dose of methohexital?
5–7 minutes
This short duration is useful in specific clinical settings.
What is the mechanism of action of methohexital?
GABA-A receptor agonist
This enhances GABAergic activity in the CNS.
Which of the following is a known clinical effect of methohexital?
Sedation and hypnosis
It is primarily used for its hypnotic properties.
Which of the following procedures is methohexital commonly used for?
Procedural sedation for electroconvulsive therapy (ECT), doesn’t lower seizure threshold
Its unique properties make it suitable for ECT.
Which of the following is a side effect associated with methohexital?
Seizure-like myoclonic movements
These movements may occur during administration.
Is Methohexital classified as an ultra-short-acting barbiturate?
Yes
This classification indicates its rapid onset and short duration.
Does Methohexital have strong analgesic properties?
No
It is not effective for pain management.
Do the hypnotic effects of methohexital wear off quickly due to redistribution?
Yes
This property facilitates rapid recovery from sedation.
Can Methohexital cause excitatory phenomena such as hiccups and myoclonus?
Yes
These side effects are noted during its use.
Is Methohexital safe for use in patients with a history of porphyria?
No
It can precipitate acute porphyric crises.
Does Methohexital increase seizure threshold, making it ideal for seizure suppression?
No
In fact, it lowers the seizure threshold.
Is respiratory depression a potential risk with methohexital administration?
Yes
Monitoring is crucial to manage this risk.
What is the typical induction dose of methohexital for adults?
1–2 mg/kg IV (50-120 mg)
This dosage is used for various procedures requiring sedation.
What is the onset time for methohexital when administered intravenously?
10–30 seconds
This rapid onset is advantageous for procedural sedation.
How long does a single IV dose of methohexital typically last?
Approximately 5–7 minutes
This allows for quick recovery post-sedation.
What receptor system does methohexital primarily act on?
GABA-A receptors (enhances GABA activity)
This mechanism is key to its sedative effects.
List two side effects commonly associated with methohexital.
Myoclonic movements, respiratory depression, laryngospasm
These side effects necessitate careful patient monitoring.
In what scenario is methohexital especially preferred over other agents?
During electroconvulsive therapy (ECT)
Its properties make it particularly suited for this procedure.
Why should methohexital be avoided in patients with porphyria?
It can precipitate an acute porphyric crisis due to enzyme induction
This is a critical consideration in patient safety.
Does methohexital provide muscle relaxation or analgesia?
No, it provides sedation/hypnosis but lacks muscle relaxation and analgesia
It is not suitable for procedures requiring pain control.
