Pharm Cholinoceptor Blockers & Cholinesterase Regenerators

Front 1

Question: Signs of atropine overdose include?

Back 1

Symptoms caused by cholinergic blockade, also hyperthermia (eg., infants), flushing, decreased salivation, cycloplegia, psychosis, tachycardia, urinary retention (watch out for BPH)

Front 2

Question: What is the most dangerous effect of belladonna alkaloids in infants and toddlers?

Back 2

Hyperthermia

Front 3

Question: What is the MOA of scopolamine?

Back 3

Competitive antagonist at muscarinic receptors.

Note: allosteric inhibitors are often reversible, but because they do not bind to the same site, they are not competitive with the agonist.

Front 4

Question: What drug causes vasodilation that can be blocked by atropine?

Back 4

Bethanechol, which causes vasodiltation by activating muscarinic receptors.

Front 5

Question: What drug has a very high affinity for the phosphorus atom in parathion and is often used to treat life-threatening insecticide toxicity?

Back 5

Pralidoxime.

Front 6

What is a chemical antagonists used to regenerate active cholinesterase? What is its MOA and its use?

Back 6

Pralidoxime is used to treat PTs exposed to insecticides, such as parathion, or to nerve gases.

It has a extremely high affinity for the phosphorus atom in organophosphate insecticides; therefore, the pralidoxime are able to bind to the organophoshpate and displace it from the cholinesterase.

Front 7

Question:

Atropine:

Cyclopentolate:

Scopolamine:

Ipratropium:

Benztropine:

Back 7

Very well absorbed.

Well absorbed into the eye.

Long duration of action. Used for antimotion sickness.

Quaternary amine (therefore permanently charged) and poorly absorbed from the airways.

Tertiary, lipid soluble, penetrates into CNS well.

Front 8

Question: What can be blocked by atropine?

Back 8

Tacycardia caused by infusion of acetylcholine.

Note: atropine blocks muscarinic receptors and inhibits parasympathomimetic effects.

Front 9

Question: The animal is anesthetized.

Drug X caused a 50 Hg rise in mean BP in the control animal, no BP change in the ganglion-blocked animal, and a 75 mm mean BP rise in the atropine-pretreated animal.

Drug X is probably similar to?

Drug Y is probably similar to? In graph, BP is decrease when there was no blocker; BP decreased more so with ganglion blocker; BP increase and decreased with muscarinic blocker.

Back 9

Nicotine. Drug X causes an increase in BP that is blocked by a ganglion blocker but not by a muscarinic blocker. Not EPI since its effects are produced at alpha receptor, not in the ganglia.

Acetylcholine. Drop in BP greater in presence of ganglion blockade, suggesting that compensatory sympathetic discharge might have blunted the full depressor action of drug Y in the untreated animal.

Front 10

Question: What is the sign that would distinguish between an overdose of a ganglion blocker vs. a muscarinic blocker?

Back 10

Postural hypotension is a sign of sympathetic blockade, which would occur with ganglion blockers but not muscarinic blockers.

Front 11

Question: What causes cyclospasm rather than cycloplegia (paralysis of accommodation) when used topically in the eye?

Back 11

All antimuscarinic agents can cause cycloplegia (and ganglion blockers).

Physostigmine is an indirect-acting cholinomimetic and causes cyclospasms.

Front 12

Question: Ordinary doses of atropine may be hazardous to the elderly PTs because?

Back 12

Atropine can elevate intraocular pressure in PTs with glaucoma. Antimuscarinic agents icnrease the intraocular pressure.

Elderly men have a higher risk of urinary retention due to BPH.

Front 13

Question: Accepted therapeutic indications for the use of antimuscarinic drugs include?

Benztropine

Dicyclomine, glycopyrrolate

Homatropine, cyclopentolate, tropicamide

Ipratropium, tiotropium

Oxybutynin

Scopolamine

Trospium

Back 13

Antiparkinsonism

GI--peptic ulcer

Mydriasis, cycloplegia

Asthma, COPD

Urinary urgency, incontinence

Motion sickness

Urinary urgency

Front 14

Question: What is the expected effect of a therapeutic dose of an antimuscarinic drug?

Back 14

M1 and M3: mediate increase in IP3 and DAG in target tissues (intestine, salivary glands).

M2: heart; decrease in cAMP and increase in K permeability.

**Antimuscarinic agents block these effects

Front 15

What are two receptor-selective M1 antagonist?

Back 15

Pirenzepine, telenzepine

Front 16

What determines the lipid solubility of drugs, such as those who work in the CNS or the eyes.

What about those who are selective for the gut, bladder, bronchi, etc.?

Back 16

Presence or absence of charged (quaternary) amine groups.

The charge molecules are polar; therefore, less likely to penetrate a lipid barrier.

Those selective for gut, bladder, and bronchi use quaternary amine groups to limit penetration through the BBB to prevent CNS complications.

Front 17

What is the prototypical non-selective muscarinic blocker, derived from atropa belladonna?

What is special about it?

Back 17

Atropine

Due to its tertiary amine, it is relatively lipid-soluble and well distributed to the CNS and other organs.

Front 18

Location of M3 receptors, and the EFFECT of the BLOCK.

Back 18

Eye: cycloplegia, mydriasis

Bronchi: bronchodiltation

BV: block of muscarinic vasodilation; not manifest unless a muscarinic agonist is present.

Front 19

Location of M1, M3 receptors, and the EFFECT of the BLOCK

Back 19

GI: relaxation, slowed peristalsis, reduced salivation

GU tract: relaxation of bladder wall, urinary retention.

Glands: Marked reduction of salivation; moderate reduction of lacrimation, sweating; less reduction of gastric secretion.

Front 20

Location of M2 receptors, and the EFFECT of the BLOCK.

Back 20

Heart: initial bradycardia, especially at low doses, then tachycardia.

M2 receptors in the SA node.

Front 21

Muscarinic blocking agents act like what? Therefore, their blocking effects can be overcome by?

Back 21

Competitive pharmacologic antagonists.

Increased concentration of muscarinic agonists.

Front 22

What muscarinic blocker is used for motion sickness?

What muscarinic blocker for adjunct therapy for parkinsonism when PTs become unresponsive to L-dopa?

Back 22

Scopolamine

Benztropine

Front 23

What muscarinic blocker are used to cause mydriasis and cycloplegia?

Back 23

Homatropine and tropicamide are used in ophthalmic solutions for retinal examination.

Atropine can be used to?

Front 24

What muscarinic blocker are used for bronchodilation in asthma and COPD. What is special about this drug?

Back 24

Ipratropium.

Although not as efficacious as beta-agonists, it is less likely to cause tachycardia and arrhythmias in sensitive PTs, such as COPD PTs.

Front 25

What two muscarinic blockers where used to treat peptic ulcers but were not as effective as H2 blockers or PPI and produce more SE?

What M1 blocker is used in Europe for peptic uclers?

Back 25

Atropine and propantheline

Pirenzepine

Front 26

What muscarinic blocker is used to reduce urgency in mild cystitis and reduce bladder spasms after urologic surgery?

Back 26

Oxybutynin

Front 27

What are the predictable SE of atropine SE?

Other SE?

Back 27

Lack of sweating (which can lead to hyperthermia, which is most serious in children and infants), salivation, and lacrimation; tachycardia; in the elderly: acute angle-closure glaucoma and urinary retention, esp with BPH; constipation and blurred vision.

Sedation, delirium, hallucinations, flushing from dilation of the cutaneous vessels.

Note" Dry as a bone, red as a beet, mad as a hatter"

Front 28

What are the contraindications of antimuscarinic agents?

Back 28

May cause hyperthermia in infants.

PTs with closed-angle glaucoma

Men with BPH

Front 29

What were the two ganglionic nicotinic receptor blockers used for hypertension? What else can they be used for?

Back 29

Hexamethonium, mecamylamine.

Text book mentions mecamylamine's benefit for smoking cessation. FA states "put a HEX on smokers (nicotine) to help them quite.

Front 30

What are the SE of ganglionic nicotinic receptor blockers?

Back 30

Due to interruption of sympathetic control:

Marked venous pooling, postural hypotension, dry mouth, blurred vision, constipation, and SEVERE sexual dysfunction.

Front 31

What are neuromuscular blocking drugs used for?

What are the nondepolarizing group?

What is the only member of the depolarizing group, and what is it used for and what may occur with its usage?

Back 31

Complete skeletal muscle relaxation in surgery.

Tubocurarine (prototype). Shorter-acting: pancuronium, atracurium, vecuronium.

Succinylcholine (nicotinic agonists): produces fasciculations during induction of paralysis. PTs may complain of muscle pain after its use.