Drugs for Common Eye Problems

Drugs for Common

Eye ProblemsCecilia A. Jimeno, M.D.

Ateneo School ond Medicine & Public Health

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Anatomy & Physiology

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Topical Ophthalmic Drugs: ConsiderationsThey must be absorbed into the anterior

chamber

They may be administered at different frequencies depending on whether they are in ointment or solution form

Ointments: have a longer duration of action (2-4 hrs) than drops

They must be relatively easy to administer for client compliance

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INTRODUCTION: Tips on using Ophthalmological Preparations

Ophthalmological preparations are sterile but once opened they have the potential to be contaminated

Hence, dropper tips should NOT touch any surface

Maximum volume accommodated by the lids is 30μl; usual drop size of a standard eye drop bottle is 20 μl which will stimulate tearing for 5 minutes

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TIPSOnly one drop should be placed in the eye

at a time since by sheer volume it will just spill over

Allow a 5 minute interval between 2 consecutive eye drops

Some pts cannot tolerate ointments because of blurring of vision and the deposition on the eyelids (unacceptable cosmetic appearance and discomfort)

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TIPS

Hence, prescribe drops during the day and ointments at night

Moreover, if necessary, drops should precede ointments because the latter impedes the absorption of the former

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KINETICS: ADMETopical drugs exert their effect by absorption

via the cornea and conjunctival vessels

Excess drug is cleared via the lacrimal apparatus through the nasal mucosa and the nasopharynx ----- access to systemic circulation [and hence, systemic side effects]

Hence, instruct patients on manual nasolacrimal occlusion and eyelid closure for 1 to 2 min to decrease systemic absorption

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Outline (based on PNDF)

1. Anti-infective agents2. Anti-inflammatory agents

- Steroids - NSAID’s

3. Diagnostic agents4. Drugs used in glaucoma

Cholinergics Beta-arenoceptor blocking drugs (Beta blockers) Adrenergic agonsts Prostglandin analogues Carbonic anhydrase inhibitors Hyperosmotic agents

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Outline

6. Local anesthetics (not included)

7. Mydriatics and Cycloplegics (Anti-cholinergics)

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Anti-Infective Agents: generalAvoid indiscriminate use of broad

spectrum antibiotics, or

The use of antibiotics for excessively long periods of time

Caution on use of combined antibiotics & steroid preparations

RATIONAL PRESCRIBING: To prevent emergence of resistant organisms To avoid ADR’s (toxic eye reactions) To avoid unnecessary expense

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Anti-Infective Agents (general principles)

For maximal effect on ocular and periocular tissues, the properly dosaged and diluted IV antibiotic preparations may also be injected through the ff routes: subconjunctival, intracameral, intravitreal and retrobulbar areas

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ChloramphenicolBroad spectrum, bacteriostatic against

most Gm (+), Gm (-) and anaerobic organisms

Resistance is increasing esp for hospital strains of staphylococci (50%)

High lipid solubility: good therapeutic evels in the aqueous humor

No route of admin can achieve good levels in the vitreous

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ChloramphenicolINDICATIONS: superficial infections of the eye

caused by susceptible bacteria (used only when less toxic drugs are contraindicated or ineffective)

Local drug toxicity is rareConsider systemic absorption ff topical ophtalmic

application: “gray baby” syndrome, urticaria, allergic reactions (rash), bone marrow suppression (e.g. aplastic anemia)

Pregnancy Risk: CEye ointments (BID-TID) or drops (hourly or q

6hrs)

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Erythromycin

Macrolide: gram positive cocci (staph, strep) and bacilli ; some gm (-) cocci (Neisseria) & bacilli (H. Influenzae, Moraxella, Chlamydiae, Treponema)

Recommended for prevention of neonatal ophthalmia

Pregnancy Risk Category: B

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Erythromycin (cont)

IndicationsSuperficial infections of the eye caused by

susceptible orgsAdjunct to oral anti-infective therapy of

Chlamydia infections (trachoma, inclusion conjunctivitis)

Prophylaxis of ophthalmia neonatorum from both gonococci and Chlamydia

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Erythromycin (cont)

Dose: as eye ointmentBacterial infections: OD to BIDChlamydial ophtalmic infections: BID

daily for 2 mos or BD for the first 5 days of each month for 6 mos

Prophylaxis of ophthalmia neonatorum: 1 cm ribbon of 0.5% ointment into each conjunctival sac immediately after birth: new tube for each neonate (single use)

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OxytetracyclineBacteriostatic against gm (-) [Pseudomaonas

aeruginosa, Entorobacteriacae] and gm (+) bacteria and against Rickettsia, Chlamydia, Mycoplasma, spirochetes, fungi & viruses

Penetrate ocular tissues better than other anti-infectives because of their high lipid solubility

Same indications as ErythromycinSystemic absorption possible : serious dental &

skeletal effectsPregnancy risk category: DEye ointment

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Gentamicin

Bactericidal for gm (-) aerobic organisms through bacterial ribosomal inhibition

Limited bioavailability: After topical application , much of the drug is bound to the iris and choroidal pigment

For superficial infections of the eye caused by susceptible orgs: Pseudomonas aeruginosa, E. Coli, Enterobacter, Klebsiell, Proteus, Serratia

Pregnancy risk: COintment 2-3x/d, drops q1-4 hr

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Tobramycin

Also an aminoglycoside against gm (-) orgs

Unlike gentamicin, has poor activity against Enterococcus and Mycobacterium

When inflammation is severe, there is a combined tobramycin + dexamethasone preparation (eye drops and ointment)

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Framycetin

Aminoglycoside closely related to the neomycin group; bactericidal & active against both gm (+) and gm(-) bacteria found in superficial eye infections (staph, Pseudomonas, coliforms, and Pneumococci)

Treatment of local eye infections (Conjunctivitis, blepharitis) due to susceptible organisms; corneal abrasions, ulers and burns

Eye drops, 1 drop 3-4x/d

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AciclovirPurine analog, 1st or 2nd gen antiviral specific

for local treatment of Herpes simplex keratoconjunctivitis and varicella zoster viral infection

Highly effective effective viral DNA polymerase inhibitor in affected cells

For local treatment of HSV 1 and 2, varicella zoster infections affecting eye

Apply eye ointment to cover all lesions 5x/d for 14 days to start as soon as with signs & sx

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Ganciclovir

Purine analog much like acyclovir but differs by an additional hydroxymethyl group on the side chain with wider spectrum of activity

HSV 1 and 2, Herpes varicella-zoster, EBVInhibits viral DNA synthesis by competitive

inhibition of viral DNA polymerase and is incorporated into viral DNA as DNA chain terminator

Has potential to cause cancer, birth defects, azospermia (unlikely for topical but possible)

Pregnancy Risk category: C

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Trifluridine

Thymidine analog which inhibits DNA polymerase and incorporates itself into DNA

Very effective against HSV 1 and 2,and vaccinia. Inhibits CMV and adenovirus in vitro

Precaution: may impair wound healing (post-op and thinned corneas)

Pregnancy risk category: C

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Fusidate sodium (fusidic acid)Antibiotic derived from Fusidium coccineumInhibits protein synthesis in bacteria, active

against a wide range of gm (+) orgs esp staphy & Strep and some gm (-) orgs (pneumococus, Neisseria, Hemophilus, Moraxella, Corynebacterium)

No known cross-resistance with other antibioticsStable to bacterial beta-lactamasesPenetrates well into the aqueous humorDrops suspension: 1 drop q 12 h

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Ofloxacin

One of the 4 quinolones, bactericidal to a large number of gm (+) and gm (-) orgs through inhibition of DNA gyrase

For Staph aureus, H. influenzae, Pseudomonas aeruginosa, E. Coli, Klebsiella & enterobacteriacae, anerobes, legionella, Neisseria gonorrhea, Chlamydia trachomatis

Pregnancy risk category: C

Eye ointment, Eye drops solution

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Povidone-iodine (topical)Used as an epitheolytic agent causing

destruction of corneal epithelium; Does not remove viruses or enter live

cellsCocaine inactivates this agent; should

not be used for corneal anesthesiaIndicated for superficial dendritic forms

of herpes simplex keratitits when aciclovir and ganciclovir are not available

Used for peri-operative preparations of the conjunctiva and periocular skin

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Anti-inflammatory Agents

STEROIDAL

NSAID

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STEROIDAL

WARNING: Intake or application of corticosteroids to the eye may induce an attack of or aggravate open angle glaucoma

Inhibit inflammatory response of whatever cause: mechanical, chemical or immunologic agents

Inhibit redness, edema, exudation, capillary dilatation, fibroblastic proliferation and fibrin deposition, and cellular infiltration & migration of leukocytes and phagocytes, collagen deposition and cicatrization

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Steroids

Stablize lysosomal membranes with prevention of release of kinins, inhibition of prostaglandin synthesis, and with chronic use decrease Ab production

Following instillation into the conjunctival sac, corticosteroids are absorbed into the aqueous humor and systemic absorption may occur

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STEROIDS: IndicationsCorneal & conjunctival inflammation such

as allergic keratoconjunctivitis, episcleritis, immune viral interstitial keratitis

To decrease inflammation and rejection in corneal transplant

For uveitis, iritis and cyclitis, scleritisCorneal, conjunctival, and scleral injuries

from chemical, radiation and thermal burnsTreatment of post-op inflammation

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Steroids: contraindications

Microbial, viral, fungal and tuberculous infections of the eye, unless these infections are controlled by appropriate chemotherapy, and use is under close supervision of a specialist

Precaution: some preparations contain sulfite, which may cause allergic reactions

Chronic use may cause corneal perforation

Example: prednisolone, dexamethasone drops suspension

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Combination of Antibiotics & Steroids

Sulfacetamide + Prednisolone: eye drops suspension – 10% sulfacetamide + 0.25% prednisolone (as acetate), 5 mL bottle

Tobramycin + dexamethasone:Eye Drops Suspension: 0.3% tobramycin +

0.1% dexamethasone, 5 mL bottle Eye Ointment: 0.3% tobramycin + 0.1%

dexamethasone, 3.5 g tube

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NSAID’s

Used for local treatment of ocular inflammation without the disadvantages of steroids

E.g. diclofenac eye drops suspension

Reduces leukocyte accumulation and exudation into the chamber fluid

Has good penetration into the ant chamber

Re-epithelialization of the corneal epithelium is not inhibited by local diclofenac treatment

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NSAID’s: Indications1. Inhibition of intra-operative miosis during

cataract surgery

2. Treatment of macular edema

3. Chronic conjunctivitis, ketaoconjunctivitis, keratitis, episcleritis

4. Painful post-traumatic conditions of the cornea and conjunctiva

5. Pre-op and in short- and long-term post-operative inflammatory process, to reduce ciliary and conjunctival injection

6. Corneal margin ulcers

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NSAID’s: precautions

Use with caution on pts with known bleeding tendencies, or on medications that prolong bleeding

Pregnancy risk category: B

Generally well tolerated with only mild transient burning

Examples: Nepafenac Eye Suspension: 1 mg/mL, 5 mL bottle

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DIAGNOSTIC AGENT: Fluorescein

Yellow water-soluble dibasic that produces an intense green fluorescence in alkaline medium

An indicator dye for the diagnosis of corneal epithelial defects or abrasions, & detection of foreign bodies; for testing the patency of the nasolacrimal drainage, fitting of contact lenses, etc

IV preparation is used to study the aqueous secretion of the ciliary body; for fluorescein angiography, and vitreous fluorophotometry

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DRUGS USED IN GLAUCOMA

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Anatomy & Physiology

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Flow of aqueuos humor

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Pathophysiology of glaucoma

Increased intraocular pressure causes optic nerve damage, visual field deterioration and eventually blindness

Degree of damage depends on the level of the IOP and the chronicity of the conditio

Major therapeutic objective: reduce IOP urgently to arrest the damage to the optic nerve

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Therapeutic options

• Options for lowering IOP include– the use of topical or systemic medications,– laser trabeculoplasty,– surgery to improve outflow facility, and– cyclodestructive laser to reduce aqueous

production.

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Treatment of GlaucomaPrimary open-angle glaucoma is

primarily treated medically, while angle closure glaucoma and congenital glaucoma are treated surgically, although short term drug therapy should be initiated to decrease intra-ocular pressure prior to surgery

IOP may be decreased by increasing the rate of outflow (drainage) of aqueous humor from the anterior chamber OR decreasing rate of production

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Glaucoma Medications Used for Chronic Treatment

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CHOLINERGIC AGONISTS (miotics)Parasympathomimetics which duplicate the

effects of acetylcholineExerts effects on muscarinic receptors of

the ciliary body stimulating the contraction of the longitudinal muscle fibers inserting to the scleral spur which then widens the valve-like pores of the trabecular meshwork facilitating outflow of aqueous humor

Possibly also a direct effect on the cholinergic receptors of the meshwork itself

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Pupilary constriction is NOT an imp’t factor for pressure reduction in open-angle glaucoma but is relevant in angle closure glaucoma

Constriction of pupil pulls the peripheral iris away from the trabecular meshwork

Other effects: vasodilatation of blood vessels of the conjunctiva, iris and ciliary body & inc permeability of blood-aqueous barrier leading to vascular congestion & ocular inflammation

CHOLINERGIC AGONISTS (miotics)

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Contraindications: cause a breakdown of the blood-aqueous barrier- they are contraindicated in pts with acute ant chamber inflammation, pupillary block glaucoma, neovascular glaucoma

Caution in elderly (miosis leads to decrease in ambient light reception/dark adaptation).

Retinal detachment may rarely occur because of the drug-induced pull on the peripheral retina as the iris-lens diaphragm is pulled forward


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Parasympathomimetics(cholinergic agents)

Generic nameTrade name

Mechanism of action

Efficacy* and dosing

Considerations

pilocarpine 1%, 2%, 4%Isopto Carpine

pilocarpine gel 4%Pilopine HS

Increases facility of outflowof aqueous throughconventional trabecularoutflow pathway

Pilocarpine lowers IOP in1 hour and lasts6–7 hours

Pilocarpine: QID

Pilopine HS: HS

Carbachol: TID

Reduces IOP by 15–25%

• Contraindications: Uveitis-related and neovascular glaucoma, aqueous misdirection syndrome

• Side effects: Miosis, myopia with accommodative spasm, brow ache, retinal detachment, intestinal cramps, bronchospasm

• Precautions: Axial myopia, history of rhegmatogenous retinal detachment, or peripheral retinal disease predisposing to retinal detachment

• May be used with caution in pregnancy

carbachol1.5%, 3%Isopto Carbachol

*Values reported are relative change (%) from baseline (peak to trough effect).

Canadian Ophthalmological Society evidence-based clinical practice guidelines for the management of glaucoma in the

adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.04/20/23

• Systemic side effects from parasympathetic stimulation: rare, tachycardia, bronchospasm, nausea, vomiting, diarrhea, abd pain, int cramps, tightness in the urinary bladder


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Beta-adrenoceptor Blocking drugs

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Review of Beta-adrenergic receptors

• Beta-1 receptors: cardiac tissue – inotropism, tachycardia, inc cardiac conduction time

• Beta-2 receptors: lungs – bronchodilation• In the eye, primary receptors appear to be Beta-

2 (mainly in the ciliary process); blockade results in reduction of aqueous humor thus reducing the IOP in eyes with or without glaucoma

• FIRST CHOICE agents for treatment for open-angle, angle-closure, inflammatory glaucoma

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Beta-blockers

• Combination therapy: additive effects are seen with miotics, epinephrine, and especially carbonic anhydrase inhibitors

• Caution: there may be consensual drop in IOP in the contralateral untreated eye, due to both systemic absorption and direct diffusion through shared blood circulation

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Beta adrenergic antagonistsGeneric nameTrade name

Mechanism of action


Considerations

Selective beta-1antagonistbetaxolol 0.25%Betoptic S

Decreases aqueousproduction

BID


• Better tolerated than non-selective agents, but not as effective

• Relative side effects and contraindications same as non-selective agents

Non-selective beta antagonists

timolol† 0.25%, 0.5%Timoptic

timolol gel-formingsolution 0.25%, 0.5%Timoptic XE

BIDDaily for Timoptic XE


• Additive to most IOP-lowering agents• Side effects: Exacerbates obstructive

pulmonary diseases such as asthma, slows heart rate and lowers BP. May mask symptoms of hypoglycemia in patients with diabetes on insulin or insulin secretagogues

• Best-tolerated class from ocular standpoint, some dry eye symptoms

• Absolute contraindications: Patients with asthma, COPD, sinus bradycardia, or greater than first-degree heart block. Precaution: Not recommended in patients with life-threatening depression

• May be used with caution in pregnancy. Fetal heart monitoring for bradycardia and arrhythmia may be indicated periodically

levobunolol 0.25%, 0.5%Betagan

BID


*Values reported are relative change (%) from baseline (peak to trough effect).†Timolol may be used during lactation. Punctal occlusion is recommended following drop instillation to reduce systemic absorption, as timolol in particular may appear in breast milk.



Alpha-2 Adrenergic Agonists

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Alpha-2 Adrenergic Agonists

• MOA: decrease IOP by increasing aqueous outflow facility and possibly by decreasing the rate of aqueous humor formation

• For open angle glaucoma; may be used with miotics, B-blockers, and carbonic anhydrase inh

• Do NOT use for narrow occludable angle glaucoma as mydriasis may cause angle closure

• May cause discoloration of contact lens

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Alpha-2 adrenergic agonists


Mechanism of action


Considerations

apraclonidine 0.5%, 1.0%Iopidine

Decreases aqueous production (prevents severe elevation of IOP following laser procedures)

Maximum effect in 4–5 hours

Duration of effect: 8–12 hours


• High rate of allergy limits use of apraclonidine for chronic treatment

For chronic use of brimonidine:• Contraindications: Children,

patients taking monoamine oxidase inhibitors

• Side effects: Dry mouth, lid retraction, allergy (more common with apraclonidine), conjunctival injection, somnolence, fatigue, headaches, hypotension

• May be used with caution in pregnancy

brimonidine 0.2%Alphagan

brimonidine 0.15%Alphagan-P(using Purite as preservative)

Decreases aqueousproduction and increases uveoscleral outflow

TID if mono-therapy, BID if adjunctive therapy

Duration of effect: 8–12 hoursReduces IOP by 20–30%




Prostaglandin Anaogues

• Endogenously produced naturally occurring chemical mediators

• Reduces IOP by enhancing uveoscleral aqueous flow without significantly affecting other parameters of aqueous humor dynamics

• Efficacy persists even with chronic use

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Prostaglandin derivatives


Mechanism of action


Considerations

bimatoprost 0.03%Lumigan

Increases uveoscleraloutflow

Bimatoprost may alsoincrease trabecularoutflow

Dosing once daily

IOP lowering starts 2–4 hours after administration

Maximum IOP- lowering often takes 3–5 weeks from start of treatment

Reduces IOP:latanoprost 28–31%travoprost 29–31%bimatoprost 28–33%

• Side effects: Iris colour changes, conjunctival hyperemia, burning, stinging, foreign-body sensation, eyelash change (length, thickness, color; reversible after cessation), cystoid macular edema in aphakia and pseudophakia, possible reactivation of herpes keratitis, possible anterior uveitis

• Should be avoided in pregnancy, as prostaglandin F2-alpha can cause uterine contraction and influence fetal circulation

latanoprost 0.005%Xalatan

travoprost 0.004%Travatan




Carbonic Anhydrase Inhibitors

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• Carbonic anhydrase is an enzyme which influences the production of bicarbonate in the ciliary body allowing diffusion of sodium ions into the posterior chamber making the aqueous humor hypertonic ---- attracts water by osmosis

• CAIs inhibit carbonic anhydrae in the ciliary processes thereby reducing aqueous secretion

• Indicated for open and angle-closure glaucoma, esp for control of acute angle-closure glaucoma


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Carbonic anhydraseinhibitors — systemic


Mechanism of action


Considerations

acetazolamidemethazolamide

Decreases aqueousformation

Acetazolamide:125–250 mg PO QID

Methazolamide:25–50 mg PO TID


• Indicated when topical medication is not effective

• May lead to hypokalemia• Contraindications: When sodium

and potassium blood levels are depressed, as in kidney or liver disease; in sickle cell anemia

• Side effects: Parasthesia, gastrointestinal symptoms, depression, decreased libido, kidney stones, blood dyscrasias, metabolic acidosis, electrolyte

• Imbalance• Precautions: Allergy to

sulfonamides, pregnancy (teratogenic effects reported), and nursing mothers




• ACETAZOLAMIDE: oral, well absorbed from the gut; decrease in IOP is achieved 60 min after oral intake, peaks in 4 hr and lasts 6-12 hrs

• 250 mg tablet• Side effects: electrolyte imbalance, metabolic

acidosis, anorexia, diarrhea, wt loss, drowsiness, sedation, confusion


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Carbonic anhydraseinhibitors — topical


Mechanism of action


Considerations

brinzolamide 1%Azopt

Decreases aqueousFormation

Azopt: BIDReduces IOP by 15–22%

Trusopt:Monotherapy: TIDAdjunctive to topical beta blockers: BIDReduces IOP by 15–22%

• Side effects: Ocular burning and discomfort

• Precautions: May increase corneal edema with low endothelial cell count and (or) corneal endothelial dysfunction (e.g., Fuchs dystrophy). Combined oral and topical carbonic anhydrase inhibitors not recommended in this patient population

• Not well studied in pregnancy, and should probably be avoided due to concerns with oral agents and teratogenicity

dorzolamide† 2%Trusopt

*Values reported are relative change (%) from baseline (peak to trough effect).†Dorzolamide may be used during lactation. Punctal occlusion is recommended following drop instillation to reduce systemic absorption, as timolol in particular may appear in breast milk.



Hyperosmotic Agents

• Lower IOP by inducing rapid increase in blood osmolality creating an osmotic gradient between plasma & the ocular fluid leading to diffusion of water from the eye to the iris, choroidal and retinal vessels, and out to the peri-ocular vessels resulting in ocular hypotonia

• Used pre-operatively and in acute glaucoma

• GLYCEROL (oral glycerin): most widely used oral hyperosmotic agent for treating acute glaucoma

• MANNITOL: intravenous

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Documentation ofmedical management

RecommendationMonitoring of patients should include documentation of the IOP (method and time measured), patient confirmation of and frequency of medications used, as well as the time of their last medication administration [Consensus].



Other drugs: Mydriatics & cycloplegics

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Mydriatics & Cycloplegics (Anti-cholinergics)

• Warning: may cause an increase in IOP • Pupillary dilatation (mydriasis) and ciliary muscle

paresis or paralysis (cycloplegics) are the result of anti-cholinergic drug use via blockage of the parasympathetic innervation

• Atropine, Tropicamaide, Cyclopentolate

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THANK YOU VERY MUCH!

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Drugs for Common Eye Problems

Documents

toxic drugs

standard eye

admetopical drugs

topical ophthalmic drugs

common eye problemscecilia

adrs toxic eye reactionsto

systemic circulation

orthe use of antibiotics