Unit 7 - 2 Pharmacology

Front 1

Why should pts with chronic glaucoma avoid antimuscarinics?

Back 1

muscarinic stimulation will prove drainage by two mechanisms:

1. miosis stretches the iris to reduce anatomial occlusion at the angle
2. miosis plus ciliary muscle contraction will stretch the smoth trabecular muscle meshwork that opens to the Canals o fSchlemm to drain aqueous humor

Front 2

Antimuscarinic drugs effect on pupil

Back 2

Mydratic; leave sympathetics unopposed

Front 3

Alpha adrenergic drugs effect on pupil

Back 3

mydratic bc they stimulate contraction of the radial iris muscles

Front 4

parasympathetic effect on iris muscles

Back 4

stimulates the circular (sphincter) muscle to contract)

Front 5

Other causes of mydraisis

Back 5

darkness
sexual arousal -- oxytocin
kappa-opioid effects e.g., analgesic dose of pentazocine; morphine/heroin overdose, central effect
mu-opioid withdrawal (analgesic doses morphine/heroin cause miosis, central effect)
5HT2A agonists (serotonin syndrome)

Front 6

Tx of acute closed angle glaucoma

Back 6

Surgical emergency; pre op drugs, tx w iridotomies (slit in iris to enlarge pupil)

drugs = miotic (pilocarpine) or osmotics (mannitol) for pre-op

Front 7

Increased cup:disc ratio/cupping is indicatative o fwhat

Back 7

Increased IOP in glauoma causing optic nerve damage

Front 8

what class of drug can precipitate acute angle closure glaucoma

Back 8

mydriatics; iris radial muscle contracts blocking of canal of schlemm

Front 9

what class of drugs can improve acute angle closure glaucoma

Back 9

miotics; iris sphincter contracts opening up flow

Front 10

Cholinergics in the eye (acetylcholine)

Back 10

Parasympathetic innervation of the iris = contraction of iris sphincter muscles = improves outflow in acute angle glaucoma

Front 11

Phenylephrine

Back 11

Alpha agonist = sympathomimetic mydriatic agent = dilates pupil, vaso constriction

Front 12

Tropicamide, cyclopentoate

Back 12

Parasympathetic mydriatic cycloplegic = muscarinic antgaonist = dilates pupil and paralyzes the ciliary muscle

Front 13

Dipiprazole

Back 13

Alpha antagonist = constricts pupil = reverse mydriatics

Front 14

Pilocarpine

Back 14

Muscarinic agonist = constricts pupil = reverse mydriatic

Front 15

When is cycloplegia unwanted (i.e., when would you choose phenylephrine instead of tropicamide)?

Back 15

When the mydriatic effect is merely to facilitate fundoscopic exam, cycloplegia imposes unnecessary inconvenience.

Front 16

Difference between phenylephrine (alpha agonist) and tropicamide (muscarinic antagonist) in evaluating the eye?

Back 16

tropicamide causes cycloplegia (paralyzes ciliary muscles) while phenylephrine doesnt

Front 17

When is cycloplegia desirable (i.e. you give tropicamide or cyclopentolate = muscarinic antagonists)

Back 17

pain relief from ciliary muscle spasm caused by inflammation (uveitis); optometry to obtain an accurate refraction

Front 18

Adverse effects of mydriatics (phenylephrine)

Back 18

bright light → photophobia and pain
acute angle-closure glaucoma attack
systemic adrenergic effects: resistance to bronchodilators in asthma, ↑ heart block

Front 19

adverse effects of mydriatic cycloplegics (tropicamide, cyclopentolate)

Back 19

bright light → photophobia and pain
blurred vision
loss of near vision
 perception of depth/distance
acute angle-closure glaucoma attack
systemic anticholinergic effects: confusion, falls, dry mouth, tachycardia

Front 20

why do topical eye drugs take awhile to produce opthalmic effects?

Back 20

the tear layer has aqueous and lipid components that the drug will partition into and has to saturate to create a concentration gradient that favors penetration of the cornea
the outer epithelial layer of the cornea is hydrophobic, so only lipophilic drugs penetrate readily; water soluble drugs penetrate slowly
the middle stromal layer of the cornea is hydrophilic, and thus delays lipophilic drugs,
inner endothelial layer of the cornea is hydrophobic, thus traps water soluble drugs in the middle stroma as they gradually penetrate the corneal epithelium

Front 21

why do topical eye drugs take esp long to produce effects in pts with dark brown eyes

Back 21

darker iris due to more melanin; most of the drugs have affinity for melanin, and drug bound to melanin is not free to bind receptor, so therapeutic response in patients with darkly pigmented irides is slower and less certain.

Front 22

timolol

Back 22

B-antagonis used to decrease IOPt; decreases production of aqueous humor by ciliary body; good efficacy with fewest ocular adverse effects; caution in asthma and can cause bradycardia

Front 23

brimonidine

Back 23

alpha agonist to decrease IOP; decrease aqeuous humor production; avoids the cardiopulmonary adverse effects of the B-antagonist timolol


may cause dry eyes, blurred vision, irridated eyelids

Front 24

latanoprost

Back 24

prostaglandin analog to decrease IOP; increase outflow of aqueous humor by activation of metalloproteinases in ciliary body  breakdown of extracellular matrix  lower viscosity and therefore less resistance to outflow through the trabecular meshwork and uveoscleral routes

side effects = longer lashes; darkening brown iris and eyelids (permaent); clouds soft contact lenses (i.e. incompatible)

Front 25

pilocarpine

Back 25

muscarinic receptor agonist (cholinergic agonist); constricts pupil and contracts ciliary sphincter muscle -> stretching of trabecular meshwork = facilitates outflow of aqueous humor

lots of adverse effects

Front 26

dorzolamide

Back 26

carbonic anhydrase inhibitors; slows formation of bicar -> decreased sodium and water transport in ciliary processes to decrease aqueous humor production

Front 27

mannitol

Back 27

administered preop before ocular surgery; acute closed angle glaucoma attack