Ophthalmology: Drugs

OPHTHALMOLOGY: DRUGS

Here's a file containing the compilation of the drugs that are mostly used in ophtho and of course, asked during the ward tests and prof table vivas. Everything is pretty haphazardly stated in the other files, so I hope this will prove helpful to all of you, as much as it did for me when I created it.

Note: You don't have to memorize all the side effects of the drugs but just have some basic knowledge about the main ones so you're able to answer whenever you're asked, especially if there's a specific side effect that you need to remember. Same old pharmacology tricks.
The important parts are: the mechanism of action of the drug, the clinical uses, and the contraindications, and you're good to go! Lastly, for the cycloplegics, half-life is something you definitely want to remember.

Reminder: Review this diagram before jumping ahead!



Class
Drug
MOA
S/Es
Uses  
non-selective B-blocker 
Levobunolol
Blockage of B1,B2 receptors. Blockage of B2 (rich in ciliary body epithelium) reduces AQ production, lowering IOP
Ocular: 
burning, stinging, blepharo-conjunctivitis, Keratitis (rare, dec. corneal sensitivity after prolonged use)
Systemic: Orthostatic Hypotension, Dec. in HR and BP, breathing problems in asthmatics and COPD patients, itching
Ocular HTN
Chronic OAG
No effect in ACG
non-selective B-blocker 
Timolol
Blockage of B1,B2 receptors. Blockage of B2 (rich in ciliary body epithelium) reduces AQ production, lowering IOP
Ocular: Eye irritation, burning sensation, eye redness, superficial punctate keratopathy, corneal numbness
Systemic: bronchospasm, arrhythmia etc.
Anti glaucoma,
Ocular HTN
CA inhibitor (topical)
Dorzolamide
Decreased production of AQ by blocking CA action
Ocular stinging, burning, itching, punctate keratitis, and bitter taste, allergy, renal stones
Glaucoma (as a combo with Timolol maleate)
Combination of the above two



Used when Timolol is not sufficient alone
Fluoroquinolone
Moxifloxacin
Bactericidal, interferes with DNA synthesis by inhibiting DNA topoisomerase 2, and 4
Tendonitis, tendon rupture, phototoxicity, rashes, dizziness, headache, GI distress, prolong QT interval
corneal ulcers, eye infections
Aminoglycoside
Gentamicin, tobramycin
Inhibit bacterial protein synthesis, bactericidal
Nephrotoxicity, ototoxicity, skin rxns, NM blockade leading to muscle weakness, nausea
Bacterial ulcers, eye infections

Polymyxin, Neomycin, Bacitracin

Hypersensitivity, rash, edema of the lids, chemosis
Antibacterial eye ointment - treatment for superficial infections of external eye and its adnexa e.g. superficial punctate keratitis, blepharitis, conjunctivitis. S.auerus, H. flu, S.pneumo, E. coli 


Tobcydex- Tobramycin Dexamethasone

Tobramycin: Ototoxicity, nephrotoxicity, rash
Dexamethasone: blurred vision, dec. vision or other changes, eye pain or redness, sensitivity of eye to light
Chalazion, pre-op, infectious conditions
Cholinomimetic
Pilocarpine
Acts at muscarinic receptors (M3) to cause MIOSIS and pull and contraction of cililary muscle, opening of TM and drainage of AQ
Irritation of the eye, increased tearing, headache, and blurry vision.Other side effects include allergic reactions and retinal detachment, accommodative spasm
All types of glaucoma as an adjunct to surgery except congenital. in ACG, reduce IOP first and then use it. 
Anti-muscarinic
Cyclopentolate
(DOA: 24h)
Blocks Muscarinic receptors and causes dilation of pupil and is a cycloplegic
increase in pressure inside the eye, which is of particular concern when there is a predisposition toward or a presence of glaucoma. Burning sensations, photophobia, blurred vision, irritation, conjunctivitis, keratitis, and other issues. 
All types of dilated eye exams, but tropicamide is preferred
Mydriasis, cycloplegia for diagnostic eye exams
Anti-muscarinic
Tropicamide
(DOA- 4-8h)
Blocks Muscarinic receptors and causes dilation of pupil and is a cycloplegic
Blurring of vision, redness, may ppt an attack of Acute glaucoma, allergies
Shorter DOA
Dilated eye exams. For cycloplegic refraction.
Pre op and pre exam ophthalmic dilation
Anti-muscarinic
Atropine sulphate
(DOA- 7-14 days)
Hompatropine-up to 4-5 days
Blocks Muscarinic receptors and causes dilation of pupil and is a cycloplegic
Blurring of vision
Acute and chronic uveitis and corneal ulcers, sec glaucoma, to rule out accommodative squint, to do cycloplegic refraction to determine type of error.
Contraindication: ACG
Corticosteroid 
Prednisolone acetate
immunosuppressive
Steroid induced glaucoma, cataract
systemic: fluid retention, osteoporosis, Cushing’s, mania, immunosuppression 

to reduce post op inflammation, non infective keratitis, uveitis
(to reduce swelling, redness, itching, allergic rxns)
Alpha 1 agonist
Phenylephrine HCL
stimulates dilator pupillae - causes mydriasis without cycloplegia 
Frequent transient burning or stinging, headache or brow-ache , blurred vision, reactive hyperemia, transient keratitis, sensitivity to light,
Rise in BP in predisposed individuals 
decongestant, mydriatic (ophthalmoscopy, ocular surgery, posterior synechiae prevention, anterior uveitis, post- iridectomy. 
Alpha 2 agonist
Brimonidine
Decreased production of AQ by decreasing cAMP production via stimulation of Gi. and increased uveoscleral outflow. (The increased uveoscleral outflow from prolonged use may be explained by increased prostaglandin release due to α adrenergic stimulation. This may lead to relaxed ciliary muscle and increased uveoscleral outflow)
itching, dry nose and eyes, drowsiness
Anti-glaucoma (OAG, Ocular HTN)
Lubricant
PolyAcrylic acid(VisolGel)
Tear substitute 
allergies, discoloration of contact lenses
Dry eyes, tear fluid substitute 
Artificial tears- 
Polyethylene glycol, glycerin, polyvinyl alcohol
Tear substitute 
allergies, discoloration of contact lenses
Dry eyes, tear fluid substitute 
Fluoroquinolone
Ofloxacain
Bactericidal, interferes with DNA synthesis by inhibiting DNA topoisomerase 2, and 4
Allergy, puffiness of eyes, tearing, itching, irritation, lacrimation, dryness 
Bacterial ulcer, conjunctivitis
Local Anesthetic
Proparacaine (ALCAINE)
Antagonist to voltage gated sodium channels
Allergy, irritation, redness, stinging, keratitis
To numb the eye- topical anesthesia of cornea and conjunctiva, for tonometry, gonioscopy etc
Mast cell stabiliser 
Cromogil- Sodium Chromoglycate
Mast cell stabilizer 
irritation, blurring of vision 
eye allergy symptoms

Lari Lube GEL
Petroleum mineral oil
Allergy, discoloration of contact lens, irritation
Dry eyes
Corticosteroid 
Dexamethasone
immunosuppressive
Burning, itching blurred vision, cataracts glaucoma, corneal rupture, dry eyes, raised IOP. open angle glaucoma, visual defects 
Reduces inflammation, not used in acute infections
Ophthalmic Hypertonic saline
Sodium chloride
Draws water out of swollen cornea
Burning sensation, irritation, blurring of vision, red eyes
For drawing water out of a swollen cornea-Corneal edema
Prostaglandin analogue
Travoprost
PG analogue; (of PGF2 alpha) increases outflow of aqueous from the eyes. acts as an agonist at the prostaglandin F receptor, increasing outflow of aqueous fluid from the eye and thus lowering intraocular pressure.
red eyes, blurry vision, eye pain, dry eyes, and change in color of the eyes, cataract
OAG, Ocular HTN
NSAID
Nepafenac
Blocks COX and PG production reducing pain and inflammation
Stinging, burning, eye redness, headache, vision changes
to relieve eye pain, irritation, and redness following cataract eye surgery. 
Dye
Fluorescin Sodium


Stains abnormal cornea
Conj. abrasions: Yellow/orange
Corneal abrasions/ulcers: bright green
Foreign bodies: surrounded by green ring
Diagnostic purposes: Goldmann tonometer
Fitting of a hard contact lens


Another useful note: Just have a general idea about the different half lives of the corticosteroids; It won't just help you in ophthalmology, but also in other aspects of medicine.

Comparative oral corticosteroid potencies
Name
Terminal half-life (hours)
Cortisol (hydrocortisone)
8
Cortisone
8
 Fludrocortisone acetate
24
Triamcinolone
12–36
Prednisone
16–36
Prednisolone
16–36
Methylprednisolone
18–40
Dexamethasone
36–54
Betamethasone
36–54

That's all. I hope this was helpful. If anything's missing, (there might be, but these are the most commonly asked drugs i.e. 9/10 times) feel free to add more to your list. If there is any kind of error, I apologize. Happy studying. 

Comments

Popular posts from this blog

Final Year Surgery Exam: Important topics

FSc Premedical Guide - How to fly high..

Final Year Medicine Exam - Important and high-yield topics