drugs acting on eye 5

8/3/2019 Drugs Acting on Eye 5

1/48


2/48

DRUGS ACTING ON EYE

BYMAI SAID SHOELA

UNDER SUPERVISION OF

PRF. DR. SAFAA EL REWANY

PROFESSOR OF PHARMACOLOGY

FACULTY OF MEDICINE

UNIVERSITY OF ALEXANDRIA


3/48

OBJECTIVES

LIST MAIN GROUPS OF DRUGS APPLIED ON THEEYE AND THEIR CLINICAL APPLICATIONS

DISCUSS THE LOCAL EFFECTS OF AUTONOMIC DRUGSON THEIR RECEPTOR SITES IN THE EYE WITHRELEVANCE TO THEIR CLINICAL APPLICATIONS

IDENTIFY THE LINES OF TREATMENT OF SOME EYEDISEASES AS GLAUCOMA AND CONJUNCTIVITIS


4/48

STRUCTURE OF THE EYE

ANATOMICALLYEYE COMPOSED

OF

ANTERIORCHAMBER

POSTERIORCHAMBER


5/48

ANTERIOR CHAMBER OF EYE

INCLUDES

CORNEA IRIS LENSAQUEOUSHUMOUR


6/48

THE CORNEA

CORNEAL OR CONJUNCTIVAL REFLEX

Cornea & sclera are supplied by sensory nerves

When the cornea is touched, corneal reflex isinitiated i.e. the eye blinks on touching thecornea with a piece of cotton


7/48

DRUGS ACTING ON CORNEA

INCLUDES

TEAR SUBSTITUTES

LUBRICATING AGENTS

LOCAL ANAESTHETICS DIAGNOSTIC DYES

TOPICALANTI-INFLAMMATORY TOPICAL ANTI-INFECTIVEDRUGS


8/48

LOCAL ANAESTHETIC DRUGS

INCLUDES:1. Surface anesthesia eye drops for :

a. Tonometry: measurement of IOPb. Removal of corneal foreign bodies

2. Infiltration anesthesia :Removal of cataracts


9/48

DIAGNOSTIC DYES

%1Fluorescein

Used for diagnosis ofcorneal ulcers

Denuded epithelium isstained bright green

%1Rose Bengal

Used for diagnosis dryeye

Dead cells are stainedred


10/48

-TOPICAL ANTIINFLAMMATORY DRUGS

INCLUDES

1. Steroidal anti-inflammatory drug

Used for inflammation of anterior segment ofeye as allergic conjunctivitis

2. Non-steroidal anti-inflammatorydrugs

Have anti-prostaglandins action

Example: Ketophenac sodium


11/48

INFECTIVE-TOPICAL ANTIDRUGS

INCLUDES

TOPICALANTI-BIOTICS

NEOMYCINCHLORAMPHENICOL

FLUOROQUINOLONES

TOPICALANTIFUNGAL

NYSTATINSOLUTION

TOPICALANTIVIRAL

AGENTS

ACYCLOVIRFOR DENDRITICCORNEAL ULCER


12/48

TEAR SUBSTITUTES ANDLUBRICATING AGENTS

EXAMPLE

1. Methyl cellulose2. Polyvinyl alcohol

USES1. Formation of artificial tears in dry eye conditions

as Sjogrens syndrome

2. Contact lens solution


13/48

THE IRIS

MUSCLES

SPHINCTERPUPILLAE MUSCLE

DILATORPUPILLAE MUSCLE

PARASYMPATHETICM3 RECEPTOR

SYMPATHETICALPHA 1 RECEPTOR


14/48

LIGHT REFLEX

PRINCIPLE

Narrowing of pupil (miosis) when the eye is

stimulated by light

This miosis is due to contraction of constrictorpupillae muscle i.e. light reflex depends on

integrity of parasympathetic supply of the eye Parasympatholytics abolish light reflex


15/48

THE LENS

ACCOMODATION REFLEX It is the ability to increases the convexity of the

crystalline lense to obtain a clear image of anobject at various distances

This is mediated through theparasympathetically innervated ciliary muscle,

whose contraction causes suspensory ligamentsrelaxation thus increasing the lense curvatureand diopteric power leading to accomodation for

near vision


16/48

THE AQUEOUS HUMOUR

It is formed of highly vascularized ciliary bodyprocesses that absorb sodium selectively via

carbonic anhydrase enzyme(70%) and ATPasesystem

The aqueous humour circulates through thepupil and is drained in the canal of Schlemm

then to episcleral veins

Normally there is balance between aqueoushomour formation and outflow and this keepsintraocular pressure within normal range (10-

21mmHg)


17/48

CHANGES IN PUPIL SIZE

MIOSIS NORMAL PUPIL MYDRIASIS


18/48

AUTONOMIC DRUGS ACTINGON THE EYE

INCLUDES

MIOTICS MYDRIATICS


19/48

MIOTICS

INCLUDES

PARASYMPATHOMIMETICS

SYMPATHOLYTICS MORPHINE

BY STIMULATION OFEDINGER WESTEFAL

NUCLEUS

ASGUANETHIDINE


20/48

PARASYMPATHOMIMEYICS

MECHANISM OF ACTION

They stimulate M3 receptors in ciliary muscle

and constrictor pupillae muscle leading to:

a. Miosis: constriction of the pupil

b. Accomodation for near vision

c. Reduce intraocular pressure: as when the pupilis constricted, the anterior chamber angle is

widened and this facilitates the drainage through

Canal of Schlemm


21/48

PARASYMOATHOMIMETICS

INCLUDES

CHOLINESTERS CHOLINOMIMETICALKALOIDS

ANTI-CHOLINESTERASES


22/48

CHOLINOMIMETIC ALKALOIDS

Pilocarpine 2%


23/48

PARASYMATHOMIMETICS

PUPIL SIZE: MIOSIS

LIGHT REFLEX: ABSENTACCOMODATION: FOR NEAR VISIONIOP: REDUCED

CONJUNCTIVAL BV:CONGESTED


24/48

MYDRIATICS

CAUSE

PASSIVEMYDRIASIS

ACTIVEMYDRIASIS

PARASYMPATHOLYTICS

SYMPATHOMIMETICS COCAINE


25/48

PARASYMPATHOLYTICS

Paralysis of sphincter pupillae muscle

PUPIL SIZE: Mydriasis (Passive)LIGHT REFLEX: ABSENT

ACCOMODATION: Lost for near visionIOP: Increased in susceptible

people only


26/48

PARASYMPATHOLYTICSINCLUDES

ATROPINE 1%LAST FOR 7-10 DAYS

ATROPINESUBSTITUTES

HOMATROPINE 2%FOR >24 hrs

CYCLOPENTOLATE 1% for1 day

TROPICAMIDE 1% for 6hrs

PARASYMPATHOLYTICS


27/48

THERAPEUTIC USES

1. Fundus examination & diagnosis ofrefractory errors

2. To break recent adhesions between theiris & lens in anterior uveitis

3. Treatment ofacute iritis &iridocyclitis

as they relief pain resulting from cilliarymuscle spasm

PARASYMPATHOLYTICS


28/48

SYMPATHOMIMETICS

MECHANISM OF ACTION

They produce active mydriasis by sympatheticnerve fibers that are motor to radial musclethrough action on 1 receptor

They do not affect light reflex or accommodation

They are vasoconstrictors so the reduce vascularcongestion of conjunctival BVs

EXAMPLE

Ephedrine sulphate, Phenylephrine & Dipivefrin


29/48

COCAINE

MECHANISM OF ACTION

1. It produces active mydriasis as it potentiates

sympathetic response by: Decreasing re-uptake of released

catecholamines

2. It preserves light reflex

3.Abolishes corneal reflex by its localanesthetic action


30/48

CONJUNCTIVITIS

INCLUDES

BACTERIALCONJUNCTIVITIS

ALLERGICCONJUNCTIVITIS


31/48

BACTERIAL CONJUNCTIVITIS

DEFINITION

IT IS INFLAMMATION OF THECONJUNCTIVA ASSOCIATED WITH

MUCOPURULENT DISCHARGE,

REDNESS AND EYELIDS EDEMA


32/48

MANAGEMENT

INCLUDES

ASTRINGENT

EYE DROPS

TOPICALANTIMICROBIAL

AGENTS

EYE LOTIONS HOT FOMENTS


33/48

EYE LOTIONSTo wash off the discharge

Example: Bland eye lotions

Boric acid lotion 4%

HOT FOMENTSAre applied locally in order to relief edema and pain

TOPICAL ANTIMICROBIAL AGENTSLocal eye drops every 1-2hrs/day & eye ointment at night

Example: Neomycin, tobramycin


34/48

ALLERGIC CONJUNCTIVITIS

DEFINITION

IT IS ACUTE ALLERGY DUE TOEXPOSURE TO ALLERGEN .

THE PATIENT PRESENT WITHREDNESS OF EYES WITH ITCHING

AND LACRIMATION


35/48

MANGEMENT

INCLUDES

TREATMENT OFACUTE ATTACK

PROPHYLACTICTREATMENT

ANTI-HISTAMINICEYE DROPS

GLUCOCORTICOIDEYE DROPS

MAST CELLSTABILIZERS


36/48

ANTI-HISTAMINIC EYE DROPS

Example: Levocabastine

Antazoline (+)

GLUCOCORTICOIDS EYE DROPS

Precaution: We must exclude viral dendritic ulcer& glaucoma

MAST CELL STABILIZERSExample: Na cromoglycate


37/48

GLAUCOMA

DEFINITION

IT IS A GROUP OF DISEASES THAT HAVE INCOMMON A CHARACTERISTIC OPTICNEUROPATHY WITH ASSOCIATED VISUALFIELD LOSS FOR WHICH THE ELEVATED

INTRAOCULAR PRESSURE IS ONE OF PRIMARYRISK FACTORS


38/48

CLASSIFICATION

INCLUDES

CLOSED-ANGLEGLAUCOMA

OPEN-ANGLEGLAUCOMA


39/48

ANGLE GLAUCOMA-CLOSED

It is associated with ashallow anteriorchamber

Acute & painful rise of IOP isoften precipitated that mustbe controlled on anemergency basis with drugsor prevented by iridectomy


40/48

ANGLE GLAUCOMA-OPEN

Outflow of AH throughthe trabecularmeshwork-Schlemms

canal venous system isimpaired

It is a chronic conditiontreated medically,

aiming to slow the rate ofdisease progression toprevent significant visualimpairment


41/48

MEDICAL MANAGEMENT OFGLAUCOMA

INCLUDES

SYMPATHO-MIMETICS

PROSTAGLANDINANALOGUES

PARASYMPATHO-MIMETICS

-BLOCKERS DIURETICS


42/48

BLOCKERS-

INCLUDES

NON-SELECTIVE BLOCKERS

TIMOLOL MALEATETOPICAL EYE

DROPS

MECHANISM OF ACTIONTimolol blocks beta receptors on the cilliaryprocesses resulting in decreasing aqueous

production

It is treatment of choice in open-angleglaucoma


43/48

DIURETICS

INCLUDES

HYPEROSMOTICAGENTS

CARBONICANHYDRASEINHIBITORS

MANNITOLI.V

ACETAZOLAMIDEORAL

I.V IN EMERGENCY

DORZOLAMIDETOPICAL EYE DRPS

MECHANISM OF ACTION OF

CARBONIC ANHYDRASE INHIBITORSThey inhibit carbonic anhydrase in the

cilliary body, which prevents bicarbonatesynthesis resulting in a fall in Na

transport and aqueous flow

MECHANISM OF ACTION OFHYPEROSMOTIC AGENTS

It acts by withdrawing fluid from the eye

and reducing vitreous volume


44/48

SYMPATHOMIMETICS

INCLUDES

AND

AGONISTS2 AGONIST

DIPIVEFRIN HCLTOPICAL EYE DROPS

BRIMONIDINE TARTRATETOPICAL EYE DROPS

MECHANISM OF ACTION OF AND AGONISTS

It lowers the IOP by a balance between and adrenoreceptors stimulation1. mediated VC of the cilliary BVs will

decrease the aqueous flow

2. 2 mediated effect will increasetrabecular meshwork drainage

CONTRAINDICATION

Angle-closed glaucoma

2MECHANISM OF ACTION OF

AGONIST

1. It reduces AH production2. It increases uveoscleral outflow (secondary

pathway for aqueous outflow 20%)

O G OG


45/48

PROSTAGLANDIN ANALOGUES)2(F

Latanoprost :topical eye drops

MECHANISM OF ACTION

1. It enhances the uveoscleral outflow of theaqueous

2. It increases blood flow to the optic nerve thatmay contribute in retinal neuroprotection


46/48

PARASYMPATHOMIMETICS

Pilocarpine HCL: topical eye drops or gel

MECHANISM OF ACTION

It increases aqueous outflow by widening of thetrabecular meshwork

SIDE EFFECTS

Blurred vision and ache over the eye

DRUGS CONTRAINDICATED IN


47/48

DRUGS CONTRAINDICATED INGLAUCOMA

Topical & systemic corticosteroids due to thepossible increase in trabecular meshwork

inducible glucocorticoid response (TIGR) gene

expression as an assumed mechanism foroutflow obstruction

Strong vasodilators as nitrites as they mayIncrease aqueous humour formation

Cycloplegic drugs as atropine


48/48

drugs acting on eye 5

Documents