Drugs Block 3

Question 1

Atropine

Answer 1

Inhibits parasympathetic nervous system. Produces cylcloplegia.

Also causes failure of eye to focus.

Question 2

Cocaine

Answer 2

Blocks axoplasmic neuronal reuptake pump of Norepi. Will dialate if sympathetic innervation is intact.

Negative test indicate’s Horner’s syndrome. Test cocaine then amphetamine.

Question 3

Amphetamine

Answer 3

MOA: Reverses axoplasmic pump stimulating release of norepi. If response = normal postganglionic. If no response to amphetamine = no postganglionic nerve.

Test cocaine then amphetamine.

Question 4

Nicotine

Answer 4

Activates nicotinic receptor releasing norepinepherine, but also activates parasympathetics causing miosis which is more common.

Question 5

Pilocarpine

Answer 5

Muscarinic agonist. Used to determine cause of miosis and to treat glaucoma by enhancing aqueous humor drainage through trabecular meshwork and canal of schlemm.

If eye responds with miosis then problem is with nerve (CN III palsy)

If eye does not respond to pilocarpine then problem has to be with the eye itself (Atropinic mydriasis)

Question 6

Physostigmine

Answer 6

Anticholinesterase that prevents Ach degradation

Use: Used to treat narrow angle glaucoma by enhancing aqueous humor drainage through trabecular meshwork and canal of schlemm

Question 7

Ectothiophate

Answer 7

Anticholinesterase that prevents Ach degradation

Use: Used to treat narrow angle glaucoma by enhancing aqueous humor drainage through trabecular meshwork and canal of schlemm

Question 8

Terazosin (-azosin)

Answer 8

Alpha-1 receptor antagonist that is not used to treat eye disease but can have ocular side effects.

Question 9

Reserpine

Answer 9

Norepinephrine depleting agents that can have occular side effects of miosis/ptosis

Question 10

Timolol (-olol)

Answer 10

Beta blocker that decreases aqueous humor formation.

Question 11

Lantanoprost

Answer 11

MOA: Prostaglandin derivative that increases uveo-scleral outflow of aqueous humor (flow through the ciliary muscle).

Most common current treatment for glaucoma

Question 12

Acetazolamide

Answer 12

Carbonic anhydrase inhibitor decreasing the production of aqueous humor. (also used to decrease CSF production)

Question 13

Botulinum Toxin

Answer 13

Inhibits acetylcholine release used to treat muscle spasms.

Question 14

Phenylephrine

Answer 14

Alpha-a agonist.

Used in eye drops to dilate pupils. Also used to reverse ptosis in Horner’s syndrome.

Question 15

Epinepherine

Answer 15

Increases aqueous humor outflow and inhibits formation of aqueous humor. Used to treat glaucoma.

Question 16

Trimethoprim

Answer 16

Bacteriostatic - inhibits bacterial DHFR. Has low affinity for mammalian enzyme

Question 17

Polymixin B

Answer 17

Mechanism - Bind to LPS in the membrane creating holes ultimately leading to the release of cellular components.

Gram negative multidrug resistant coverage

Question 18

Trifluridine

Answer 18

MOA: Pyrimidine analog effective against acyclovir resistant virus because it can be phosphorylated by host kinases also making it much more toxic and should only be used topically.

Question 19

Cochlear implant

Answer 19

Small implantable electronic device that acts as acoustic transducer. Can’t restore or create nuclear hearing (cochlea is removed)

Both adults and children are candidates, but children between 2 and 6 are ideal due to auditory nerve degeneration.

Question 20

Mastoidectomy

Answer 20

Removal of mastoid bone to create a safe ear by irradicating infection. Also remove cholesteatoma.

Done to preserve hearing and vestibular structures.

Reconstruction of middle ear structures.

Question 21

Panretinal Photocoagulation (PRP)

Answer 21

Thousands of laser spots in supportive retina (retina outside macula) which leads to atrophy and decreased vascularization.

Used to treat Proliferative Diabetic Retinopathy (PDR) by preventing neovascularization

Question 22

Macrolides: Erythromycin and azithromycin

Answer 22

Mechanism: Inhibits translation by binding 23s rRNA of the 50s subunit

Spectrum: Broad coverage of respiratory pathogens, Chlymidia

Resistance: Increased efflux, hyrolysis of drub by esterases, methylation of drug binding site

Adverse effects: GI discomfort, Hepatic failure, and prolonged QT interval. Inhibitors of CYP 450

Question 23

Glycerine or Isorbide

Answer 23

Used to dehydrate eye during closed angle glaucoma emergency in conjunction with pilocarpine and acetazolamide

Question 24

Pyremethamine and Sulfadiazine

Answer 24

Sulfadiazine - blocks pteridine synthetase

Pyrimethamine - blocks parasitic DHFR

Used in conjunction to treat Toxoplasmosis

Question 25

Polytrim

Answer 25

Trimethoprim- blocks bacterial DHFR

Polymixin b - binds LPS creates holes in membrane (gram -)

Used together to treat bacterial conjunctivitis

Question 26

Polymixin and Neomycin and Hydrocortisone

Answer 26

Polymixin b - binds LPS creates holes in membrane (gram -)

Neomycin - Blocks translocation of 30s ribosomal subunit

Hydrocortisone - Block phospholipase A2 preventing inflammation

Used to treat bacterail otitis externa