Autonomics: Muscarinic Antagonists Flashcards
Parkinson’s results from decreased _________ activity and increased __________ activity.
dopamine; cholinergic
What two muscarinic antagonist can be used to treat IBS?
Hyoscyamine
Dicyclomine
_____________ (an antimuscarinic) can be used to treat heart block.
Atropine
Why is atropine used to treat bradycardia?
Because the M2 receptors on the heart cause relaxation and decreased HR; blocking this input stimulates tachycardia
What is cycloplegia?
Inability to control the ciliary muscle, leading to far sightedness; antimuscarinics can cause this, because the parasympathetic response is needed to focus on objects up close (think of the walrus with the scope – scopalamine is an antimuscarinic)
In the CNS, antimuscarinics can be used to treat __________.
Parkinson’s (think of the parking sign)
What muscarinic antagonist can be used preoperatively to decrease airway secretion?
Glycopyrrolate
Which antimuscarinic can be applied transdermally?
Scopalamine (the eyepatch on the walrus)
What two antimuscarinics distribute best to the CNS?
Benztropine (think of the Benz parked at the M1 spot) and trihexiphenidyl (think of the tri-hexi car)
What two plants contain atropine?
Atropa belladonna (used to be used to dilate women’s eyes to make them more beautiful) and Jimson weeds
What two antimuscarinics are used to treat overactive bladder?
Oxybutynin and tolterodine (think of the ox and the turtle shutting off the bladder-shaped vessel at the table)
Why do antimuscarinics make you hot?
Because they suppress the sweating response (sympathetic input, but uses acetylcholine)
What antimuscarinics are used to treat COPD and asthma?
Ipratropium and tiotropium, which block the M3 receptor (think of the caterpillar inhaling smoke: “cat-ipra-tio-tropillar”)
What are some side effects of antimuscarinic overdose?
“Mad as a hatter (from blocking M1 in the CNS), blind as a bat (cycloplegia), dry as a cracker (decreased salivation), hot as a hare (suppressed sweating), and glaucoma”
What is the technical name for dilated pupils?
Mydriasis
