Parasym Agonist Direct

Question 1

Bethanechol

Answer 1

Activates bladder smooth muscle; resistant to AChE. Acts on muscarinic receptors; no nicotinic activity. “Bethany, call me to activate your bladder.”

Question 2

Carbachol

Answer 2

Carbon copy of acetylcholine (but resistant to AChE). Constricts pupil. Used for intraoperative mio: induction.

Question 3

Methacholine

Answer 3

Stimulates muscarinic receptors in airway when inhaled. Challenge test for diagnosis of asthma.

Question 4

Pilocarpine

Answer 4

Contracts ciliary muscle of eye (open-angle glaucoma), pupillary sphincter (closed-angle glaucoma); resistant to AChE, can cross blood-brain barrier. “You cry, drool, and sweat on your ‘pilow.”

Pilocarpine is beneficial in promoting salivation in patients with xerostomia resulting from irradiation of the head and neck. Sjogren syndrome, which is characterized by dry mouth and lack of tears, is treated with oral pilocarpine tablets and cevimeline, a cholinergic drug that also has the drawback of being nonspecific(many systemic side effects).

Question 5

Glaucoma

Answer 5

Optic neuropathy causing progressive vision loss (peripheral → central). Usually, but not always, accompanied by 1 intraocular pressure (IOP). Etiology is most often 1°, but can be 2° to an identifiable cause (eg, uveitis, glucocorticoids). Funduscopy: optic disc cupping (normal A vs thinning of outer rim of optic disc BI). Treatment: pharmacologic or surgical lowering of IOP.

Question 6

Open-angle glaucoma

Answer 6

Anterior chamber angle is open (normal). Most common type in US. Associated with i resistance to aqueous humor drainage through trabecular meshwork. Risk factors: † age, race († incidence in Black population), family history, diabetes mellitus. Typically asymptomatic and discovered incidentally.

Question 7

Angle-closure glaucoma

Answer 7

Anterior chamber angle is narrowed or closed. Associated with anatomic abnormalities (eg, anteriorly displaced lens resting against central iris) → t aqueous flow through pupil (pupillary block) - pressure buildup in posterior chamber - peripheral iris pushed against cornea - obstruction of drainage pathways by the iris. Usually chronic and asymptomatic, but may develop acutely.
Acute angle-closure glaucoma -complete pupillary block causing abrupt angle closure and rapid
1 IOP. Presents with severe eye pain, conjunctival erythema C, sudden vision loss, halos around lights, headache, fixed and mid-dilated pupil, nausea and vomiting. Hurts in a hurry with halos, a headache, and a “half-dilated” pupil. True ophthalmic emergency that requires immediate management to prevent blindness. Mydriatic agents are contraindicated