Drugs acting on the parasympathetic NS Flashcards
(41 cards)
Which of the following are not indirect-acting parasympathomimetics (reversible anticholinesterases)?
- Physostigmine (opthalmic)
- Carbamate insecticides
- Pyridostigmine
- Acetylcholine
- Neostigmine
- Demecarium (opthalmic)
- Edrophonium
- Endogenous acetylcholine is a direct-acting parasympathomimetic

(know neostigmine, pyridostigmine, and edrophonium)
This indirect-acting parasympathomimetic (reversible) is available as an injection (1:4000) or as oral tablets (1:1000, 1:2000).
- Neostigmine (Prostigmin)
- Pyridostigmine (Mestinon)
- Edrophonium (Tensilon, Enlon)
- Neostigmine (Prostigmin)
A patient suspected of having myasthenia gravis (flaccid paralysis and cannot stand) was treated with Pyridostigmine at a high dose and was doing well, but now he has flaccid paralysis again. He is given Edrophonium IV and it worsens the muscle weakness. This is a:
- Myasthenic crisis
- Cholinergic crisis
Cholinergic crisis (decrease dose anticholinesterase)
Cholinergic crisis- treatment with excess doses of cholinesterase inhibitor
This indirect-acting parasympathomimetic (reversible) is very fast acting with onset at 1 minute and lasts about 10 minutes.
- Neostigmine (Prostigmin)
- Pyridostigmine (Mestinon)
- Edrophonium (Tensilon, Enlon)
- Edrophonium (Tensilon, Enlon)
A patient suspected of having myasthenia gravis (flaccid paralysis and cannot stand) is given Edrophonium IV and improves his muscle function. This is a:
- Myasthenic crisis
- Cholinergic crisis
- Myasthenic crisis (increase dose anticholinesterase)
This is an autoimmune neuromuscular disorder which causes immune destruction of nicotinic receptors at motor end plates.
Myasthenia gravis
Which direct-acting parasympatholytic is a quaternary ammonium compound?
- Aminopentamide
- Atropine
- Pyridostigmine
- Glycopyrrolate
- Oxybutynin
- Propantheline
4. Glycopyrrolate
(compared to atropine, it has a slower onset of action and longer duration; it does not absorb well orally and does not cross the BBB)
What type of drug affecting the PSNS blocks autonomic effects to get sympathetic signs?
Parasympatholytics
- Direct acting
T or F. Direct-acting parasympatholytics can be called anticholinergics, antimuscarinics, and anitnicotinics.
False, only anticholinergics and anitmuscarinics (Atropine, Glycopyrrolate, Oxybutynin, Propantheline, Aminopentamide)
Which type of drug affecting the PSNS stimulates (mimics) autonomic effects to get parasympathetic signs?
Parasympathomimetics
- Direct acting (acts on a receptors)
- Indirect acting (acts somewhere close to a receptor)
- Reversible anticholinesterases
- Irreversible anticholinesterases
Which indirect-acting parasympathomimetic (reversible) is used to treat rumen atony, to stimulate GI motility, for bladder emptying, and for the reversal of competitive neuromuscular blockers (NKBs)?
- Neostigmine (Prostigmin)
- Pyridostigmine (Mestinon)
- Edrophonium (Tensilon, Enlon)
- Neostigmine (Prostigmin)
(also used to treat myasthenia gravis in dogs, but Pyridostigmine is used more often because it is longer acting)
Which of the following is not a direct-acting parasympatholytic?
- Aminopentamide
- Atropine
- Pyridostigmine
- Glycopyrrolate
- Oxybutynin
- Propantheline
- Pyridostigmine is an indirect-acting parasympathomimetic (reversible)
Which indirect-acting parasympathomimetic (reversible) is used to test for myasthenia gravis, to differentiate myasthenic crisis from cholinergic crisis, and for the reversal of nondepolarizing NMBs?
- Neostigmine (Prostigmin)
- Pyridostigmine (Mestinon)
- Edrophonium (Tensilon, Enlon)
- Edrophonium (Tensilon, Enlon) “Tensilon Test”
This indirect-acting parasympathomimetic (reversible) has gastrointestinal effects in 10-30 minutes and lasts for 4 hours.
- Neostigmine (Prostigmin)
- Pyridostigmine (Mestinon)
- Edrophonium (Tensilon, Enlon)
- Neostigmine (Prostigmin)
Which of the following is not an effect of Atropine?
- Slows gut
- Increased urination
- Bronchodilation
- Blurred vision (cycloplegia)
- Tachycardia
- Mydriasis (dilates pupil)
- Reduces salivation
- Dries secretions
- Difficulty with urination
- Increased urination
(Have to be careful of cycloplegia in horses! They will freak the fuck out!)
This indirect-acting parasympathomimetic (reversible) is available only as an injection (10 mg/mL solution).
- Neostigmine (Prostigmin)
- Pyridostigmine (Mestinon)
- Edrophonium (Tensilon, Enlon)
- Edrophonium (Tensilon, Enlon)
Which of the following is not an indirect-acting parasympathomimetics (irreversible anticholinesterase)?
- Echothiophate (opthalmic)
- Edrophonium
- Organophosphate insecticides (toxicity)
- Edrophonium is an indirect-acting parasympathomimetic REVERSIBLE anticholinesterase
All of the following are nicotinic effects of organophosphate toxicity, except:
- CNS effects
- Bronchospasm
- Muscle tremors
- Muscle weakness
- Muscle paralysis
- Tachycardia
- Mydriasis
- Bronchospasm is a muscarinic effect
(Tachycardia and mydriasis due to stimulation of sympathetic ganglia and release of [nor]epinephrine)
- *Nicotinic/ionotropic receptors affect the neuromuscular junction, autonomic ganglia, CNS, and the adrenal medulla*
- *Muscarinic/metabotropic receptors affect smooth muscles, glands, the heart, and CNS*

All of the following are muscarinic effects of organophosphate toxicity, except:
- Bronchospasm
- Bradycardia
- Emesis
- Muscle paralysis
- Lacrimation
- Diarrhea
- Urination
- Miosis
- Salivation
- Muscle paralysis is a nicotinic effect
Don’t forget DUMBBELS!
- Diarrhea
- Urination
- Miosis
- Bronchospasm
- Bradycardia
- Emesis
- Lacrimation
- Salivation
- *Nicotinic/ionotropic receptors affect the neuromuscular junction, autonomic ganglia, CNS, and the adrenal medulla*
- *Muscarinic/metabotropic receptors affect smooth muscles, glands, the heart, and CNS*

Which direct-acting parasympatholytic is available as an injectable solution and oral tablets?
- Aminopentamide
- Atropine
- Pyridostigmine
- Glycopyrrolate
- Oxybutynin
- Propantheline
2. Atropine sulfate (Atroject), systemic
(usually used as an injection)
Which direct-acting parasympatholytics treat incontinence due to detrusor muscle instability (hyperactive bladder)?
- Aminopentamide
- Atropine
- Pyridostigmine
- Glycopyrrolate
- Oxybutynin
- Propantheline
5. Oxybutynin (Ditropan)
6. Propantheline (Pro-banthine)
These are urinary and gastrointestinal antispasmodic agents that allows the bladder to fill (relaxes the detrusor muscle)
(does the opposite of what Bethanochol does)

This indirect-acting parasympathomimetic (reversible) is available as oral tablets, ER tablets, oral syrup, and injectable.
- Neostigmine (Prostigmin)
- Pyridostigmine (Mestinon)
- Edrophonium (Tensilon, Enlon)
- Pyridostigmine (Mestinon)
This indirect-acting parasympathomimetic (reversible) has an onset of 1 hour after oral dosing and lasts longer than Neostigmine.
- Pyridostigmine (Mestinon)
- Edrophonium (Tensilon, Enlon)
- Pyridostigmine (Mestinon)
(because it lasts longer, it can be given 2-3 times a day; good for patients taking the drug home)
Which indirect-acting parasympathomimetic (reversible) is used to treat myasthenia gravis in dogs?
- Neostigmine (Prostigmin)
- Pyridostigmine (Mestinon)
- Edrophonium (Tensilon, Enlon)
- Pyridostigmine (Mestinon)


