Benzodiazepines Flashcards
Where in the brain do benzodiazepines exert their
action?
The sedative effects are exerted on receptors in the cortex of
the brain, amnesia is mediated by receptors in the forebrain and
hippocampus, and the anxiolytic effects are exerted in the
amygdala, hippocampus, and limbic system.
Ouellette RG, Joyce JA.Pharmacology for Nurse
Anesthesiology. Sudbury, MA: Jones and Bartlett Learning;
2011: 53.
How do benzodiazepines exert their action on GABA
receptors?
Specific benzodiazepine receptor sites exist on a protein
complex that contains binding sites for benzodiazepines, GABA,
ethanol, barbiturates, and a chloride channel. When these
receptor sites are occupied by one of the drugs listed above,
the GABA receptor increases the frequency of chloride channel
opening which results in hyperpolarization of the postsynaptic
membrane and inhibition of neuronal transmission.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 480-481.
How do benzodiazepines affect CMRO2 and
cerebral blood flow?
They decrease CMRO2 and cerebral blood flow in a manner
similar to propofol and thiopental.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 488.
How are benzodiazepines metabolized?
Benzodiazepines are metabolized via hepatic oxidation and
glucuronide conjugation.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 488.
How is the metabolism of benzodiazepines affected
by hepatic disease?
They undergo oxidation, which is impaired in the presence of
hepatic disease.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 488.
How do benzodiazepines affect upper airway
reflexes?
Benzodiazepines decrease the swallowing reflex and the upper
airway reflexes.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 488.
How do diazepam, lorazepam, and midazolam
compare with respect to duration of action?
Diazepam is long-lasting with an elimination half-life of 36-50
hours, lorazepam is of intermediate duration with an elimination
half-life of 10-22 hours, and midazolam is short-acting with an
elimination half-life of about 2 hours.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 117.
How do the formulations of midazolam, lorazepam,
and diazepam differ? How does this affect pain on
injection?
Lorazepam and diazepam are not water soluble. They are
formulated in propylene glycol which can cause pain on
injection. Midazolam is water-soluble and formulated in an
aqueous solution that causes minimal pain on injection.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 487-488.
What is the typical IV or IM premedication dose of
midazolam? What is the typical PO premedication
dose of midazolam?
The dose for IV or IM midazolam is 0.02-0.04 mg/kg compared
to 0.4 to 0.8 mg/kg for the PO dose.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 488.
How does midazolam affect cerebral autoregulation?
Midazolam preserves the ability of the blood vessels to
vasoconstrict in response to a decrease in blood flow. Despite
a decrease in cerebral perfusion pressure, the intracranial
pressure would be relatively unaffected.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 488.
How do the anticonvulsant effects of midazolam
compare to that of diazepam?
Midazolam is more effective at preventing or terminating seizure
activity, but its duration of action is shorter.
Miller RD. Miller’s Anesthesia. 7th ed. Philadelphia: Churchill
Livingstone; 2010: 737.
How is the duration of action of diazepam affected by
aging? Renal disease? Hepatic disease?
The duration of action of diazepam is prolonged in the elderly
and in patients with hepatic or renal disease and doses should
be decreased accordingly.
Longnecker DE, Newman MF, Brown DL, Zapol WM.
Anesthesiology. 2nd ed. New York: McGraw-Hill; 2012: 699.
How does diazepam affect the carbon dioxide
response curve?
Diazepam decreases the slope of the CO2 response curve.
Unlike most other CNS depressants, however, diazepam does
not shift the curve to the right.
Miller RD. Miller’s Anesthesia. 7th ed. Philadelphia: Churchill
Livingstone; 2010: 738.
How does diazepam affect minute ventilation?
Diazepam decreases minute ventilation.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 119.
What is the only benzodiazepine antagonist
available in the United States?
Flumazenil
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 119.
