Direct Acting Parasympathomimetics. Flashcards
What receptors are affected by carbachol?
Carbachol is a potent muscarinic and nicotinic agonist.
Why does carbachol have a long duration of action?
As it is resistant to breakdown by ACHE.
What are the effects of acetylcholine?
It stimulates the autonomic ganglia to release ACH.
Carbachol can be given to treat what 3 conditions?
Rumen atony and impaction in cattle.
Impaction colic in horses.
Glaucoma in dogs.
What is rumen atony?
When there is loss of tonicitiy of the rumenal muscles leading to colic.
Why should carbachol not be the 1st drug of choice when dealing with colics?
As it is not the safest to use and it is advisable to start with a safer drug.
How does carbachol treat galucoma in dogs?
It causes contraction of the muscles of the eye and a loss of ocular fluid.
What kind of receptors are stimulated by bethanecol?
Muscarinic receptors.
Why is bethanecol a very long acting drug?
It is resistant to breakdown by ACHE.
What conditions is bethanecol used to treat?
GI Paralytic ileus.
Urinary retention due to failure of bladder muscles to contract.
Bethanecol should only be used when?
When there is no obstruction in the GI tract as it stimulates GI motility.
How does betahnecol help animals with bladder muscle weaknesses to pee?
It increases tonicity in bladder muscles so that the animal can urinate.
What is paralytic ileus?
Weakness of the GI muscles.
What are 3 naturally occurring parasympathomimetics?
Pilocarpine.
Muscarine.
Arecoline.
What receptors are affected by pilocarpine?
It is a muscarinic receptor agonist.
What conditions is pilocarpine often used to treat?
Eye conditions such as glaucoma and an inability to produce tears.
What kind of muscarinic receptors will pilocarpine act on?
M3 receptors.
How does pilocarpine treat glaucoma?
It causes contraction of the iris and the lens.
What is keratoconjunctivitis sicca?
An inability to produce tears.
What 3 conditions are carbachol and bethanecol used to treat?
GI atony.
Paralytic ileus.
Impaction colic.
What 4 conditions can bethanecol be used to treat?
GI atony.
Paralytic ileus.
Impaction colic.
Problems with the detrusor muscle of the bladder.
What parasympathomimetic can be used to treat glaucoma?
Pilocarpine and carbachol.
What are the adverse effects of parasympathomimetics?
Bronchoconstriction.
Bradycardia.
Miosis.
Increased gland secretions.
Vomiting diarrhoea.
Urinary incontinence.
