Antimuscarinics

Question 1

What is the prototype anti muscarinic?

Answer 1

Atropine

Question 2

What Antimuscarinic is used for nausea and vomiting

Answer 2

Scopolamine

AKA hyoscyamin and analogs

Question 3

What Antimuscarinic is used for Respiratory Disease?(2)

Answer 3

Ipratropium (Atrovent)

Tiotropium (Spiriva)

Question 4

What Antimuscarinic is used for incontinence? (3)

Answer 4

Oxybutynin ( Ditropan)
Tolterodine (Detroit)
Solifenacin (Vesicare)

Question 5

What Antimuscarinic is used in Opthalmology?

Answer 5

Tropicamide (Mydriacyl)

Question 6

Define Muscarinic Agonist

Answer 6

Competitive agonist of ACh at Muscarinic receptor

Question 7

What are the physical Effects of a Muscarinic Agonist

Answer 7

During if secretions:
Lacrimal, salivary, respiratory, GI decrease time and motility of GI tract.

Relaxation of the Bladder and urine retention
Bronchodilation
Increased heart rate

Question 8

What are the effects of Antimuscarinic on nervous system?

Answer 8

Sedation and Amnesia
Excitation and seizures
Antiemetic: Reduction of Vomitting
Quaternary salts don’t penetrate CNS.

Question 9

What is the Chemoteceptor trigger zone?

Answer 9

chemoreceptor trigger zone (CTZ) is an area of the medulla oblongata that receives inputs from blood-borne drugs or hormones, and communicates with other structures in the vomiting center to initiate vomiting.

Question 10

What are the common uses of Antimuscarinics?

Answer 10

Motion sickness: Scopolamine

Respiratory diseases- Asthma COPD: Tiotropium, ipatropium, aclidinium

Urinary incontinence: oxybutynin, darifenacin

Ophthalmologic as mydriatic agents ( not glaucoma)

Question 11

What are less common uses of antimuscarinics?

Answer 11

Low-dose inclusion in antidiarrheal

Antidote for poisoning with cholinesterase inhibitors or muscarinic agonists

Parkinson’s treatment: benzetropine and trihexyphenidyl

Emergency cardiac stimulation: Atropine

Pulmonary medicine

Preoperative Anesthesia

Question 12

Describe the use of scopolamine

Answer 12

Anti-motion sickness and nausea

Transdermal patch that is most effective as a prophylactic

Question 13

What are the side-effects of scopolamine?

Answer 13

Xerostomia- dry mouth
Drowsiness
Blurred Vision

Question 14

What effect does antimuscarinics have on bronchioles smooth muscle?

Answer 14

They block excitatory muscarinic receptors M3 on bronchioles smooth muscle.

Bronchiodilation

Example: Tiotropium

Available as inhalants in combination with B2 agonists.

Question 15

How do antimuscarinics help urinary incontinence.

Answer 15

Suppress premature detrusor contraction and enhance bladder storage.

Examples oxybutynin, tolterodine, solifenacin

Antimuscarinic side-effects

Question 16

Why is the Urinary Incontenance drug of choice?

Answer 16

Oxybutynin

Cheap
Short half-life
Metabolized by CYP3A4

Transdermal gel

Causes dry mouth

Question 17

Are solifenacin and darifenacin selective in the bladder?

Answer 17

No

Question 18

How are antimuscarinics used in eye exam?

Answer 18

They paralyze the ciliary muscle.

Example: Tropicamide

A different drug is used if you just want mydriasis or pupil dilation

Antimuscarinics can cause glaucoma.

Question 19

What type of drug us used for pupil dilation?

Answer 19

alpha receptor agonist

Question 20

What does antimuscarinic toxicity do to the CNS?

Answer 20

Hallucination, coma,

Question 21

Antimuscarinic poisoning makes you:

Answer 21

Red as a beet
Dry as a Bone
Blind as a bat
Mad as a hatter

Question 22

What are contraindications for Antimuscarinics?

Answer 22

Glaucoma
Prostatic Hypertrophy
Cardiovascular instability
Severe Ulcerative colitis
Children most at risk

Question 23

What drug classes have Antimuscarinic side effects?

Answer 23

Tricyclic Antidepressants
Antipsychotics 1st and 2nd generation
Antihistamine
Amantadine

Question 24

How do you treat Antimuscarinic poisoning?

Answer 24

Physostigmine crosses BBB

Or cholinesterase inhibition

Benzodiazepines for seizures

Ice baths for hyperthermia

Keep in dark for photophobia

Question 25

Why is is difficult to selectively manipulate Muscarinic Receptors:

Answer 25

The active sites are similar / highly conserved

So they need allosteric modulators