L9.Anticholinergic Drugs

Question 0

Diphenhydramine (Benadryl) is a tertiary amine used for what? Mechanism?

Answer 0

Benadryl is an antiparkinsonian agent. Benadryl works via antimuscarinic mechanisms with anticholinergic effects

Question 1

Tertiary vs quaternary amines?

Answer 1

Pharmicokinetics: Tertiary amines are non-polar amines. This means that they will get through lipid membranes, such as the BBB, and are easily absorbed. Quaternary drugs not as easily absorbed. Won’t penetrate BBB and enter CNS

Question 2

What do anticholinergic drugs do? 3 categories?

Answer 2

Block action of ACh at cholinergic receptors (muscarinic and nicotinic) throughout the body.

• Muscarinic blockers - Parasympathetic
• Ganglionic blockers (nicotinic I) - parasympathetic & sympathetic
• Neuromuscular blockers (nicotinic II) - Skeletal muscle

Question 3

The major pharmacological actions of anticholinergic drugs in the GI, Cardiovascular, eye, and urinary tract are what?

Answer 3

GI: Loss of muscle tone –> Constipation
Cardiovascular: Tachycardia
Eye: Relaxes ciliary and sphinctor muscles leading to an inability to accomodate & mydriasis (dilated pupils) respectively.
Urinary Tract: Urinary retention

Question 4

Atropine and Scopolamine are the two major naturally occurring anticholinergic drugs. What receptor do they act upon?

Answer 4

Muscarinic cholinergic receptors in the parasympathetic system

Question 5

What is the mechanism by which antimuscarinic, belladona alkaloids, work?

Answer 5

Blockade, via competitive antagonism, of acetylcholine at postsynaptic muscarinic receptors (parasympathetic).
-If concentration is pushed will also affect all autonomic system at ganglionic nicotinic receptors

Question 6

Narrow-angle glaucoma contraindicates the use of what types of drug?

Answer 6

1. Antimuscarinic (anticholinergic drugs)

2. Alpha 1 agonists

Question 7

What defines antispasmodic drugs?

Answer 7

They are tertiary amines that have little anticholinesterase activity.

Question 8

What of drug is dicyclomine (bentyl)? What is it used for?

Answer 8

It is antispasmodic antimuscarinic drug used for irritable bowel syndrome

Question 9

What type of drug is tolterodine (Detrol)? What is it used for?

Answer 9

Tolterodine (Deltrol) is a antispasmodic antimuscarinic drug used to treat bladder instability (urinary leakage).

Question 10

Tertiary amine, muscarinic blockers, mydriatics are used for what purpose?

Answer 10

To cause pupil dilation (mydriases) and cycloplegia for eye exams

Question 11

What role do antiparkinsonian agents play in the treatment of parkinson symptoms? How do they do this?

Answer 11

Antiparkinsonian drugs, such as benadryl, are used to restore the balance b/t dopamine and ACh in the CNS. This is accomplished by blocking ACh production or increasing ACh degradation by various anticholinergic drugs.

Question 12

Name two antimuscharinic, Antiparkinsonian drugs used in the initial treatment of parkinson symptoms.

Answer 12

1. Benztropine (Cogentin)

2. Diphenhydramine (Benadryl)

Question 13

What is the difference b/t depolarizing and non-depolarizing nglionic blocking agents? Give an example of each.

Answer 13

Depolarizing blocking agents initially activate ACh receptors and then hyperpolarize the receptors making further activation impossible. Non-competitive blocking agent. Ex = Nicotine
Non-depolarizing blocking agents are competitive inhibitors of ACh receptors. Ex = Mecamylamine (Inversine)

Question 14

What is the general result of neuromuscular blocking agents?

Answer 14

Skeletal Muscle relaxants/muscle paralysis by blocking cholinergic impulses propogated from somatic motor neurons to skeletal muscle cells

Question 15

skeletal muscles are not equally susceptible to the paralytic effects of neuromuscular blocking agents. What is the general order of pralaytic inducement?

Answer 15

1. At low doses small muscles, such as in eye, eyelids, speech, swallowing& fingers.
2. Limbs neck & trunk
3. Respiration. Intercostal muscles