Anticholinergics/Cholinergic Agonists Flashcards
What are the three anticholinergic drugs in current
use for anesthesia?
Atropine, scopolamine, and glycopyrrolate
Stoelting RK & Hillier SC. Pharmacology and Physiology in
Anesthetic Practice. 4th ed. Philadelphia, PA: Lippincott
Williams & Wilkins; 2006: 267.
With what receptors do anticholinergic drugs
combine?
They combine reversibly with the muscarinic cholinergic
receptors and prevent acetylcholine from binding to the receptor.
Stoelting RK & Hillier SC. Pharmacology and Physiology in
Anesthetic Practice. 4th ed. Philadelphia, PA: Lippincott
Williams & Wilkins; 2006: 266.
Will the administration of atropine or glycopyrrolate
to a parturient increase the heart rate of the fetus?
Although atropine can cross the placenta (glycopyrrolate
cannot), there is no significant change in fetal heart rate after
intravenous administration to the mother.
Stoelting RK & Hillier SC. Pharmacology and Physiology in
Anesthetic Practice. 4th ed. Philadelphia, PA: Lippincott
Williams & Wilkins; 2006: 269.
How do anticholinergics affect airway resistance?
The bronchodilatory effects of anticholinergics reduce airway
resistance and increase anatomic dead space. The effect is
more pronounced in patients with asthma and COPD.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 235.
Which of the three anticholinergics has the greatest
sedative effect?
Scopolamine has the greatest sedative effect. Atropine causes
slight sedation and glycopyrrolate has no sedative effect at all.
Stoelting RK & Hillier SC. Pharmacology and Physiology in
Anesthetic Practice. 4th ed. Philadelphia, PA: Lippincott
Williams & Wilkins; 2006: 268.
How do the anticholinergic drugs compare with
respect to their antisialagogue effect?
Scopolamine has the greatest antisialagogue effect, followed
closely by glycopyrrolate, then atropine.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 234.
How does the anticholinergics compare with respect
to their tendency to increase heart rate?
Atropine causes the greatest increase in heart rate, followed by
glycopyrrolate, then scopolamine.
Stoelting RK & Hillier SC. Pharmacology and Physiology in
Anesthetic Practice. 4th ed. Philadelphia, PA: Lippincott
Williams & Wilkins; 2006: 268.
Can the anticholinergic drugs be administered orally?
Even the lipid-soluble anticholinergics, atropine and
scopolamine, are not absorbed with enough predictability to
warrant oral administration.
Stoelting RK & Hillier SC. Pharmacology and Physiology in
Anesthetic Practice. 4th ed. Philadelphia, PA: Lippincott
Williams & Wilkins; 2006: 268.
How does the onset of an increased heart rate from
administration of IV atropine compare with
glycopyrrolate?
Atropine will produce an increase in the heart rate in about 1
minute. Glycopyrrolate takes about 2-3 minutes to increase the
heart rate.
Stoelting RK & Hillier SC. Pharmacology and Physiology in
Anesthetic Practice. 4th ed. Philadelphia, PA: Lippincott
Williams & Wilkins; 2006: 268.
Which anticholinergic is considered the safest for
use in patients with glaucoma? Which is the least
safe?
Scopolamine exhibits the greatest mydriatic effect and requires
the greatest amount of caution in patients with glaucoma.
Atropine 0.4 mg to 1 mg IV is considered safe when
administered with an anticholinesterase drug because little to
no increase in pupil size is noted. Glycopyrrolate has little to no
mydriatic effect.
Stoelting RK & Hillier SC. Pharmacology and Physiology in
Anesthetic Practice. 4th ed. Philadelphia, PA: Lippincott
Williams & Wilkins; 2006: 268.
How does the effect of atropine on the heart rate
differ between infants, young adults, and the elderly?
Vagal tone is enhanced in young adults, and the increase in
heart rate is most evident in this population. In infants, and in
the elderly, even large doses of atropine may have little effect
on the heart rate.
Stoelting RK, Hillier SC. Pharmacology and Physiology in
Anesthetic Practice. Philadelphia, PA: Lippincott Williams and
Wilkins; 2006: 270.
How do anticholinergics affect gastric function?
Administration of anticholinergics in general results in a
decrease in gastric secretions, decreased peristalsis and
intestinal motility, prolonged gastric emptying time, and reduced
lower esophageal sphincter tone.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 235.
What is ipratropium?
Ipratropium is an inhaled anticholinergic administered to
produce bronchodilation in the treatment of asthma. It is a
derivative of atropine that has limited systemic absorption from
the respiratory tract. It is used (often in combination with
albuterol) in the treatment of chronic obstructive pulmonary
disease. It exerts no change on heart rate or intraocular
pressure.
Stoelting RK, Hillier SC. Pharmacology and Physiology in
Anesthetic Practice. Philadelphia, PA: Lippincott Williams and
Wilkins; 2006: 271-272.
What are the indications for transdermal
scopolamine?
Transdermal scopolamine is useful in preventing nausea in
patients with a history of motion sickness. It also does not have
the sedative, cycloplegic, or tachycardic side effects of
parenteral scopolamine. It should be administered 4 hours prior
to the stimulus for the greatest effect.
Stoelting RK, Hillier SC. Pharmacology and Physiology in
Anesthetic Practice. Philadelphia, PA: Lippincott Williams and
Wilkins; 2006: 273.
How do anticholinergics affect gastric pH?
Anticholinergics increase gastric pH and have been used in the
treatment of peptic ulcer disease. None of them are selective
for this, however, and large doses are required to affect gastric
pH. This results in a high incidence of undesirable side effects
in many patients.
Stoelting RK, Hillier SC. Pharmacology and Physiology in
Anesthetic Practice. Philadelphia, PA: Lippincott Williams and
Wilkins; 2006: 271-272.
