Ophthalmics Flashcards
What receptor is targeted by the ocular drugs acetylcholine, pilocarpine, carbachol, and echothiophate? Are they agonists or antagonists, and direct or indirect acting?
Muscarinic receptor; all are agonists: acetylcholine, pilocarpine, and carbachol are direct, echothiophate is indirect
What are 2 therapeutic uses for acetylcholine, pilocarpine HCl, and carbachol in the eye? How do they work?
Reduce IOP in glaucoma and after cataract surgery; direct ACh agonists that cause pupillary constriction –> increased aqueous outflow
What disorder does echothiophate iodide treat, and how does it work?
Glaucoma; indirect muscarinic agonist that irreversibly binds AChE (increased ACh –> pupillary constriction –> increased aqueous outflow)
What side effects are associated with taking acetylcholine, pilocarpine HCl, carbachol, and echothiophate iodide?
muscarinic agonists cause SLUDGE (salivation, lacrimation, urination, diarrhea, GI irritation, emesis), and also bronchospasm
What receptor is targeted by the ocular drugs atropine, scopolamine, and homatropine, and how do they affect that receptor?
Muscarinic receptor antagonists
What receptor is targeted by the ocular drugs cyclopentolate and tropicamide, and how do they affect that receptor?
Muscarinic receptor antagonists
What are 2 therapeutic uses for atropine, scopolamine homatropine, cyclopentolate, and tropicamide?
Induce cycloplegia and mydriasis (ciliary muscle paralysis and pupil dilation) for eye exams, and improve comfort during uveitis (active eye inflammation)
Rank the 5 antimuscarinic agents in order from fastest to slowest recovery time.
Tropicamide (1/4 d) - cyclopentolate (1 d) - homatropine (1-3 d) - scopolamine (3-7 d) - atropine (7-12 d)
What side effects are associated with taking anticholinergics / muscarinic antagonists?
Insomnia, photophobia, urinary retention, and neurologic abnormalities (or: “dry as a bone, blind as a bat, red as a beet, mad as a hatter”)
Describe edrophonium: what kind of receptor does it affect, what is its mechanism of action, and what is its main therapeutic use?
Nicotinic (Nm) receptor agonist that works at the NMJ by destroying AChE. Used to diagnose myasthenia gravis
What receptors are targeted by the ocular drugs epinephrine, dipivefrin, hydroxyamphetamine, and cocaine; are they agonists or antagonists; and are they direct or indirect?
Adrenergic receptors; agonists; ephinephrine and its prodrug dipivefrin are direct while hydroxyamphetamine and cocaine are indirect
Which sympathetic agonist causes dilation of episcleral vessels in order to increase aqueous outflow? What ocular disease is it used to treat?
Epinephrine; glaucoma
Which sympathetic agonist prevents the reuptake of NE?
Cocaine
What sympathetic agonist is used to differentiate 1st and 2nd order neuron dysfunction from 3rd order neuron dysfunction in Horner’s syndrome, and how does it do so?
Hydroxyamphetamine. It causes NE release: if pupillary dilation occurs, the 3rd order neuron is intact, so the problem lies in a 1st or 2nd order neuron (more dangerous)
Which sympathetic agonist is a prodrug of epinephrine?
Dipivefrin