Indirect-acting ACh receptor agonists (reversible cholinesterase inhib)

Question 1

Indirect-acting ACh receptor agonists (2 main groups)

Answer 1

Cholinesterase inhibitors.

Type V phosphodiesterase inhibitors.

Question 2

Cholinesterase inhibitors (2 groups)

Answer 2

Reversible cholinesterase inhibitors.

Quasi-reversible cholinesterase inhibitors (organophosphate compounds)

Question 3

Reversible cholinesterase inhibitors (7 drugs)

Answer 3

Edrophonium
Neostigmine
Pyridostigmine
Physostigmine 
Donepezil
Galantamine
Rivastigmine

Question 4

Treatment of myasthenia gravis

Answer 4

Cholinesterase inhibitors + corticosteroids / immunosuppressant.
Thymectomy.
Cholinesterase for long-term treatment: neostigmine and pyridostigmine

Question 5

Too high or too low doses of cholinesterase inhibitors in myasthenia gravis may cause (two crises) and why.

Answer 5

Too low doses: myasthenic crisis (no ACh causes muscle weakness).
Too high doses: cholinergic crisis (too much ACh causes a depolarization blockade and muscle weakness).

Question 6

Edrophonium - MOA

Answer 6

Prevents hydrolysis of ACh by cholinesterase and increases concentrations of ACh

Question 7

Edrophonium - indications

Answer 7

Diagnosis of myasthenia gravis.

Distinguishing myasthenic crisis (decreases muscle weakness) from cholinergic crisis (increases muscle weakness).

Question 8

Reversible cholinesterase inhibitors that cross the BBB

Answer 8

Physostigmine
Donepezil
Galantamine
Rivastigmine

Question 9

Neostigmine, physostigmine, pyridostigmine - MOA

Answer 9

Act as slowly hydrolyzing substrates for cholinesterase, and increases the concentration of ACh

Question 10

Drugs used to counteract curariform drug action postoperatively

Answer 10

Neostigmine, pyridostigmine, edrophonium

Question 11

Neostigmine - indications

Answer 11

Postoperative urinary retention and abdominal distention

Question 12

Physostigmine - indications

Answer 12

Given parenterally as antidote to atropine (or other antimuscarinic) overdose

Question 13

Reversible cholinesterase inhibitors used to treat Alzheimers

Answer 13

Donepezil
Galantamine
Rivastigmine