cholinergic antagonists (blockers)

Question 1

Muscarinic Receptor Antagonists (Antimuscarinic)

Answer 1

Atropine Ipratropium Benztropine

Question 2

Nicotinic Receptor Antagonists (NN & NM)

Answer 2

Hexamethonium Mecamylamine

Question 3

Neuromuscular Blocking Drugs (Antinicotinic NM)

Answer 3

D-tubocurarine Succinylcholine

Question 4

Non-Depolarizing Neuromuscular blockers

Answer 4

D-tubocurarine

Question 5

Depolarizing Neuromuscular blockers

Answer 5

Succinylcholine

Question 6

Atropine Ipratropium Benztropine

Answer 6

Muscarinic Receptor Antagonists (Antimuscarinic)

Question 7

Hexamethonium Mecamylamine

Answer 7

Nicotinic Receptor Antagonists (NN & NM)

Question 8

D-tubocurarine Succinylcholine

Answer 8

Neuromuscular Blocking Drugs (Antinicotinic NM)

Question 9

D-tubocurarine

Answer 9

Non-Depolarizing Neuromuscular blockers

Question 10

Succinylcholine

Answer 10

Depolarizing Neuromuscular blockers

Question 11

Clinical uses and acute intoxication treatment for atropine overdose

Answer 11

Clinical Uses:

§ Antispasmodic
§ Antisecretory
§ Management of AChE inhibitor overdose
§ Antidiarrheal
§ Ophthalmology
§ Prevent vagal reaction in some procedures (pericardiocentesis)

Tx of acute intoxications:

§ Symptomatic
§ Physostigmine

Question 12

Ipratropium

Answer 12

Properties:

§ Nonselective muscarinic antagonist
§ Mainly acts on M3 in bronchial SMCs and glands when inhaled
§ Quarternary amine à no CNS absorption

Effects:

§ decreases bronchoconstriction
§ decreases bronchial secretions

Clinical uses: (inhaled)

§ chronic obstructive lung disease (first line therapy)
§ asthma (second line therapy for flares)

Question 13

Atropine

Answer 13

Characteristics:

§ Prototype of the class
§ Tertiary amine à enters CNS
§ Competes with Ach at M receptors
§ Does not distinguish among M1, M2, M3 subgroups of muscarinic receptors

Pharmacologic Effects: in order of increasing doses:

decreased secretions (salivary, bronchiolar, sweat)

mydriasis & cycloplegia

hyperthermia

tachycardia

sedation

urinary retention & constipation

behavioral excitation & hallucinations

Completely counteracts peripheral vasodilation caused by choline esters

Does not affect blood pressure when given alone

Question 14

Benztropine

Answer 14

Properties:

§ tertiary amine à CNS absorption
§ acts on muscarinic receptors in the brains
§ parasympathetic effector sites

Effects:

§ re-establish dopaminergic-cholinergic balance in patients with

Parkinson’s Disease (PD: ¯ dopaminergic à cholinergic goes

unchecked)

§ ¯GI/GU secretions, ¯ motility, ­ heart rate

Clinical uses:

§ Parkinson’s disease: second- or third line therapy
§ Parkinson’s disease secondary to antipsychotic

Question 15

•hexamethonium, mecamylamine

Answer 15

• Reduce the predominant autonomic tone
• Prevent baroreceptor reflex changes in heart rate
• Most are no longer available clinically because of toxicities

Arterioles

SANS

Vasodilation, hypotension

Veins

SANS

Dilation, decreased venous return, decreased CO

Heart

PANS

Tachycardia

Iris

PANS

Mydriasis

Ciliary muscle

PANS

Cycloplegia

GI tract

PANS

Decreased tone & motility – constipation

Bladder

PANS

Urinary retention

Salivary glands

PANS

Xerostomia

Sweat glands

SANS

Anhidrosis