What are the common drugs used for anesthesia induction and their dosages?

From the Guidelines

Propofol is the most widely used anesthesia induction drug, administered at 1.5-2.5 mg/kg IV, due to its rapid onset and short duration, as well as reduced nausea and vomiting 1.

Common Anesthesia Induction Drugs

• Propofol: 1.5-2.5 mg/kg IV, providing rapid onset (30-40 seconds) and short duration
• Etomidate: 0.2-0.3 mg/kg IV, maintains hemodynamic stability, ideal for cardiovascularly compromised patients
• Ketamine: 1-2 mg/kg IV or 4-5 mg/kg IM, preserves respiratory drive and blood pressure, useful in hypovolemic patients
• Thiopental: 3-5 mg/kg IV, though less common now, has a rapid onset

Mechanism of Action

• Propofol: acts on the GABA receptor, enhancing inhibitory neurotransmission, leading to sedation and hypnosis
• Etomidate: acts on the GABA receptor, enhancing inhibitory neurotransmission, leading to sedation and hypnosis, with minimal impact on cardiovascular function
• Ketamine: acts as an NMDA receptor antagonist, providing sedation, analgesia, and amnesia, with sympathomimetic effects
• Thiopental: acts on the GABA receptor, enhancing inhibitory neurotransmission, leading to sedation and hypnosis

Dosage Adjustments

• Patient age, weight, comorbidities, and hemodynamic status should be considered when adjusting dosages
• Elderly patients and those with significant comorbidities typically require reduced doses

Additional Considerations

• Pre-induction assessment of the airway and preparation of airway equipment is essential
• Vasopressors should be readily available to manage potential hypotension, particularly with propofol
• Neuromuscular blocking agents, such as succinylcholine or rocuronium, may be used in combination with these drugs for rapid sequence induction or longer procedures 1.

From the FDA Drug Label

For induction of general anesthesia, before administration of other anesthetic agents. Individual response to the drug is variable, particularly when a narcotic premedication is not used. The dosage should be titrated to the desired effect according to the patient’s age and clinical status Unpremedicated Patients:In the absence of premedication, an average adult under the age of 55 years will usually require an initial dose of 0.3 to 0. 35 mg/kg for induction, administered over 20 to 30 seconds and allowing 2 minutes for effect.

The common drug used for anesthesia induction is midazolam.

• The mechanism of action is not explicitly stated in the provided text, but midazolam is known to be a benzodiazepine that acts on the central nervous system to produce sedation, anxiolysis, and amnesia.
• The dosage for induction of anesthesia in unpremedicated patients is:
  • 0.3 to 0.35 mg/kg for patients under 55 years, administered over 20 to 30 seconds.
  • 0.3 mg/kg for patients over 55 years.
  • 0.2 to 0.25 mg/kg for patients with severe systemic disease or debilitation. 2

From the Research

Common Drugs Used for Anesthesia Induction

• Propofol: a widely used intravenous anesthetic for induction and maintenance of anesthesia 3, 4, 5
• Thiopentone: used as an alternative to propofol for anesthesia induction 3
• Methohexitone: used as an alternative to propofol for anesthesia induction, but has a higher incidence of excitatory effects 3
• Etomidate: used as an alternative to propofol for anesthesia induction, but has a higher incidence of adrenal suppression 3

Mechanism of Action

• Propofol: works by enhancing the inhibitory neurotransmission mediated by GABA (gamma-aminobutyric acid) 5
• Thiopentone: works by enhancing the inhibitory neurotransmission mediated by GABA 3
• Methohexitone: works by enhancing the inhibitory neurotransmission mediated by GABA 3
• Etomidate: works by enhancing the inhibitory neurotransmission mediated by GABA, and also has a suppressive effect on the adrenal cortex 3

Dosages

• Propofol: typically administered at a dose of 2-2.5 mg/kg for induction of anesthesia 6, 7
• Thiopentone: typically administered at a dose of 3-5 mg/kg for induction of anesthesia 3
• Methohexitone: typically administered at a dose of 1-2 mg/kg for induction of anesthesia 3
• Etomidate: typically administered at a dose of 0.2-0.4 mg/kg for induction of anesthesia 3

Side Effects and Considerations

• Propofol: can cause pain on injection, hypotension, and respiratory depression 4, 6
• Thiopentone: can cause hypotension, respiratory depression, and excitatory effects 3
• Methohexitone: can cause excitatory effects, hypotension, and respiratory depression 3
• Etomidate: can cause adrenal suppression, hypotension, and respiratory depression 3