Flashcards in 8 Cholinergics II Deck (22):
What are the two main classes of anticholinergics?
anti-muscarinics/parasympatholytics and anti-nicotinics
What is the main therapeutically significant difference between tertiary amines and quaternary ammoniums, and how does this dictate when and for what purpose they are used?
Tertiary amines are uncharged and exhibit good absorption across gut and conjuctival membranes, so they are often used for ocular or CNS effects.Quaternary ammoniums are positively charged and exhibit poor absorption across membranes due to poor lipid solubility, and so are often used to decrease CNS effects and increase potency at muscarinic receptors
T or F: Antimuscarinic drugs are used to induce mydriasis without cycloplegia
F; antimuscarinic drugs are used to induce both mydriasis and cycloplegia together
Atropine, homatropine, and tropicamide are all antimuscarinic drugs used in ophthalmology. Which is the longest acting? The shortest acting?
Atropine is long-actingHomatropine is intermediateTropicamide is short-acting
What effect do drugs like atropine have on the heart?
Muscarinic antagonists block vagal slowing of the heart and produce tachycardia
What effects do antimuscarinics have on the airway?
They reduce secretions and elicit bronchodilation
What effect do muscarinic antagonists have on the GI tract?
Antimuscarinics decrease smooth muscle motility and secretions in the GI tract
What effect do antimuscarinics have on salivary glands?
They reduce salivation, and may be used to treat excess salivation due to heavy metal poisoning or parkinson’s
What effect do antimuscarinics have on sweat glands?
They reduce the activity of thermoregulatory sweat glands
What is atropine fever, and why is it caused by antimuscarinics?
Atropine fever is an increased body temperature due to an impaired ability to sweat. Antimuscarinics cause this condition by inhibiting thermoregulatory sweat glands.
What effects do antimuscarinics have on the genitourinary system?
Decrease smooth muscle contraction of the bladder wall and decrease urination
T or F: Antimuscarinics are used for their CNS effects to treat parkinsons and motion sickness.
Ipratropium is a quaternary derivative of which antimuscarinic? What are some of its uses?
It is a quaternary derivative of Atropine, used for bronchodilation in patients with airway problems
Which drug is a quaternary derivative of scopolamine? For what type of illnesses is it used?
Methscopolamine; it lacks the CNS effects of scopolamine, and so is used primarily for GI diseases
Is atropine a tertiary amine or quaternary ammonium? Is it selective for either muscarinic or nicotinic receptors?
A tertiary amine; it is highly selective for muscarinic receptors with low potency at nicotinic.
What are some of the therapeutic uses for atropine? Which areas of the body are most sensitive to atropine?
Mydriasis and cycloplegia, relieves urinary incontinence, useful adjunct therapy for parkinsons, overcome poisoning by O-P or muscarine mushrooms; salivary, bronchial, and sweat glands are most sensitive to atropine
Is scopolamine a tertiary amine or quaternary ammonium? Is it selective for either muscarinic or nicotinic receptors?
Tertiary amine that has strong antimuscarinic effects
What are the main therapeutic uses for Scopolamine?
Elicits CNS depression (drowsiness, amnesia, etc), and was historically used as an adjunct for pre-anesthetic medication, used also to treat motion sickness.
Is methscopolamine a tertiary amine or quaternary ammonium? What are the main therapeutic uses?
A quaternary ammonium with no CNS effects; It is used primarily for GI diseases, but also has significant effects in inhibiting secretions of respiratory tract
Is homatropine a tertiary amine or quaternary ammonium? What are the main therapeutic uses, and what is its duration of action?
Tertiary amine derivative of atropine used as a topical mydriatic and cycoplegic agent. Duration of action is 2-4 hours
Is trihexyphenidyl a tertiary amine or quaternary ammonium? What are the main therapeutic uses?
A tertiary amine antimuscarinic used as an adjunct therapy to decrease unwanted movement and excess salivation in parkinsons patients