DRUGS ACTING ON EYEBY MAI SAID SHOELA UNDER SUPERVISION OF PRF. DR. SAFAA EL REWANY PROFESSOR OF PHARMACOLOGY FACULTY OF MEDICINE UNIVERSITY OF ALEXANDRIA
OBJECTIVESLIST MAIN GROUPS OF DRUGS APPLIED ON THE EYE AND THEIR CLINICAL APPLICATIONS
DISCUSS THE LOCAL EFFECTS OF AUTONOMIC DRUGS ON THEIR RECEPTOR SITES IN THE EYE WITH RELEVANCE TO THEIR CLINICAL APPLICATIONS
IDENTIFY THE LINES OF TREATMENT OF SOME EYE DISEASES AS GLAUCOMA AND CONJUNCTIVITIS
STRUCTURE OF THE EYEANATOMICALLY EYE COMPOSED OF
ANTERIOR CHAMBER
POSTERIOR CHAMBER
ANTERIOR CHAMBER OF EYE
INCLUDES
CORNEA
IRIS
LENS
AQUEOUS HUMOUR
THE CORNEACORNEAL OR CONJUNCTIVAL REFLEXThe cornea and the sclera are supplied by sensory nerves. When the cornea is touched the corneal reflex is initiated i.e. the eye blinks on touching the cornea with a piece of cotton
DRUGS ACTING ON CORNEAINCLUDESLOCAL ANAESTHETICS DIAGNOSTIC DYES
TOPICAL ANTI-INFLAMMATORY
TOPICAL ANTI-INFECTIVE DRUGS
TEAR SUBSTITUTES LUBRICATING AGENTS
LOCAL ANAESTHETIC DRUGSINCLUDES1. Surface anaesthesia by lidocaine eye drops for : a. Tonometry: measurement of IOP b. Removal of corneal foreign bodies 2. Profound anaesthesia by tetracaine eye drops for: Removal of cataracts
DIAGNOSTIC DYESFluorescein 1%Used for diagnosis of corneal ulcers Denuded epithelium is stained bright green
Rose Bengal 1%Used for diagnosis dry eye Dead cells are stained red
TOPICAL ANTIINFLAMMATORY DRUGSINCLUDES 1. Steroidal anti-inflammatory drug anti
Used for anterior segment of eye inflammation as allergic conjunctivitis Example: Dexamethasone
2. Non-steroidal anti-inflammatory drugs Nonanti
Have anti-prostaglandins action anti Example: Ketophenac sodium
TOPICAL ANTI-INFECTIVE DRUGSINCLUDES
TOPICAL ANTI-BIOTICS
TOPICAL ANTIFUNGAL
TOPICAL ANTIVIRAL AGENTS
NEOMYCIN CHLORAMPHENICOL CIPROFLOXACIN
NYSTATIN SOLUTION
ACYCLOVIR FOR DENDRITIC CORNEAL ULCER
TEAR SUBSTITUTES AND LUBRICATING AGENTSEXAMPLE1. Methyl cellulose 2. Polyvinyl alcohol
USES1. Formation of artificial tears in dry eye conditions as Sjogrens syndrome Sjogren 2. Contact lens solution
THE IRISMUSCLES
SPHINCTER PUPILLAE MUSCLE PARASYMPATHETIC M3 RECEPTOR
DILATOR PUPILLAE MUSCLE SYMPATHETIC ALPHA 1 RECEPTOR
LIGHT REFLEXPRINCIPLE
Narrowing of pupil (miosis) when the eye is stimulated by light This miosis is due to contraction of constrictor pupillae muscle i.e. light reflex depends on integrity of parasympathetic supply of the eye Parasympatholytics abolish light reflex
THE LENSACCOMODATION REFLEX
It is the ability to increases the convexity of the crystalline lense to obtain a clear image of an object at various distances This is mediated through the parasympathetically innervated ciliary muscle, whose contraction causes suspensory ligaments relaxation thus increasing the lense curvature and diopteric power leading to accomodation for near vision
THE AQUEOUS HUMOUR
It is formed of highly vascularized ciliary body processes that absorb sodium selectively via carbonic anhydrase enzyme(70%) and ATPase enzyme(70%) system The aqueous humour circulates through the pupil and is drained in the canal of Schlemm then to episcleral veins Normally there is balance between aqueous homour formation and outflow and this keeps intraocular pressure within normal range (10(1021mmHg) 21mmHg)
CHANGES IN PUPIL SIZE
MIOSIS
NORMAL PUPIL
MYDRIASIS
AUTONOMIC DRUGS ACTING ON THE EYE
INCLUDES
MIOTICS
MYDRIATICS
MIOTICSINCLUDES
PARASYMPATHO MIMETICS
SYMPATHOLYTICS
MORPHINE
AS GUANETHIDINE
BY STIMULATION OF EDINGER WESTEFAL NUCLEUS
PARASYMPATHOMIMEYICSMECHANISM OF ACTIONThey stimulate M3 receptors in ciliary muscle M3 and constrictor pupillae muscle leading to: a. Miosis: constriction of the pupil b. Accomodation for near vision c. Reduce intraocular pressure: as when the pupil is constricted, the anterior chamber angle is widened and this facilitates the drainage through Canal of Schlemm
PARASYMOATHOMIMETICS
INCLUDES
CHOLINESTERS
CHOLINOMIMETIC ALKALOIDS
ANTICHOLINESTERASES
CHOLINESTERS1. Carbachol 1% 2. Bethenecol 1%
CHOLINOMIMETIC ALKALOIDSPilocarpine 2%
ANTICHOLINESTERASES
INCLUDESREVERSIBLE PHYSOSTIGMINE 1% NEOSTIGMINE 3% IRREVESIBLE AS D.F.P 0.1%
PARASYMATHOMIMETICS
PUPIL SIZE: MIOSIS LIGHT REFLEX: ABSENT ACCOMODATION: FOR NEAR VISION IOP: REDUCED CONJUNCTIVAL BV: CONGESTED
MYDRIATICSCAUSE
PASSIVE MYDRIASIS
ACTIVE MYDRIASIS
PARASYMPATHO LYTICS
SYMPATHOMIMETICS
COCAINE
PARASYMPATHOLYTICSMECHANISM OF ACTIONThey cause paralysis of sphincter pupillae muscle leading to: a. Passive mydriasis b. Abolish light reflex c. Increase IOP: due to narrowing of anterior chamber angle d. Loss of accomodation for near vision: as they produce cycloplegia
PARASYMPATHOLYTICSINCLUDES
ATROPINE 1%LAST FOR 10 DAYS
ATROPINE SUBSTITUTES
HOMATROPINE 2% FOR 24 hrs EUCATROPINE 2% 3-4hrs
CYCLOPENTOLATE 1% 2hrs TROPICAMIDE1%
THERAPUTIC USES1. Fundus examination and diagnosis of refractory errors 2. To break recent adhesions between the iris and the lense in anterior uveitis 3. Treatment of acute iritis and iridocyclitis as they relief pain resulting from cilliary muscle spasm
PAEASYMPATHOLYTICS PUPIL SIZE: PASSIVE MYDRIASIS LIGHT REFLEX: ABSENT DUE TO PARALYSISOF CONSTRICTOR PUPILLAE MUSCLE ACCOMODATION: FOR FAR VISION IOP: INCREASED CONJUNCTIVAL BV: NO EFFECT
SYMPATHOMIMETICSMECHANISM OF ACTIONThey produce active mydriasis by sympathetic nerve fibers that are motor to radial muscle through action on 1 receptor They do not affect light reflex or accomodation They are vasoconstrictors so the reduce vascular congestion of conjunctival blood vessels
EXAMPLEEphedrine sulphate, Phenylephrine and Dipivefrin
COCAINEMECHANISM OF ACTION1.It produces active mydriasis as it potentiates sympathetic response by: a. Decreasing re-uptake of released recatecholamines b. Inhibits degradation of catecholamines by MAO 2. It preserves light reflex 3. Abolishes corneal reflex by its local anaesthetic action
CONJUNCTIVITISINCLUDES
BACTERIAL CONJUNCTIVITIS
ALLERGIC CONJUNCTIVITIS
BACTERIAL CONJUNCTIVITIS DEFINITIONIT IS INFLAMMATION OF THE CONJUNCTIVA ASSOCIATED WITH MUCOPURULENT DISCHARGE, REDNESS AND EYELIDS EDEMA
MANAGEMENTINCLUDES
EYE LOTIONS
HOT FOMENTS
ASTRINGENT EYE DROPS
TOPICAL ANTIMICROBIAL AGENTS
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
ASTRINGENT EYE DROPSPrecipitate proteins so decrease capillary permeability Example: Zinc sulphate 1%
TOPICAL ANTIMICROBIAL AGENTSLocal eye drops every 1-2hrslday and eye ointment at night Example: Neomycin
ALLERGIC CONJUNCTIVITISDEFINITIONIT IS ACUTE ALLERGY DUE TO EXPOSURE TO ALLERGEN . THE PATIENT PRESENT WITH REDNESS OF EYES WITH ITCHING AND LACRIMATION
MANGEMENTINCLUDES
TREATMENT OF ACUTE ATTACK
PROPHYLACTIC TREATMENT
ANTI-HISTAMINIC EYE DROPS
GLUCOCORTICOID EYE DROPS
MAST CELL STABILIZERS
ANTI-HISTAMINIC EYE DROPSExample: Levocabastine Antazoline
GLUCOCORTECOIDS EYE DROPSExample: Dexamethasone Precaution: We must exclude viral dendritic ulcer and glaucoma
MAST CELL STABILIZERSExample: Na cromoglycate
GLAUCOMADEFINITIONIT IS AGROUP OF DISEASES THAT HAVE IN COMMON A CHARACTERISTIC OPTIC NEUROPATHY WITH ASSOCIATED VISUAL FIELD LOSS FOR WHICH THE ELEVATED INTRAOCULAR PRESSURE IS ONE OF PRIMARY RISK FACTORS
CLASSIFICATION
INCLUDES
CLOSED-ANGLE GLAUCOMA
OPEN-ANGLE GLAUCOMA
CLOSED-ANGLE GLAUCOMA
It is associated with a shallow anterior chamber, in which a dilated iris can occlude the outflow drainage pathway at the angle between cornea and cilliary body In this type, acute and painful rise of IOP is often precipitated that must be controlled on an emergency basis with drugs or prevented by iridectomy
OPEN-ANGLE GLAUCOMA
The outflow of aqueous humour through the trabecular meshworkmeshworkSchlemm Schlemms canal venous system is impaired It is a chronic condition and treated medically, aiming to slow the rate of disease progression to prevent significant visual impairment
MEDICAL MANAGEMENT OF GLAUCOMAINCLUDES
-BLOCKERS
DIURETICS
SYMPATHOMIMETICS
PROSTAGLANDIN ANALOGUES
PARASYMPATHOMIMETICS
- BLOCKERSMECHANISM OF ACTION INCLUDESTimolol blocks beta receptors on the cilliary processes resulting in decreasing aqueous SELECTIVE 1 NON-SELECTIVE production It is treatment of choice in open-angle BLOCKERS BLOCKER glaucoma TIMOLOL MALEATE TOPICAL EYE DROPS LEVOBUNOLOL HCL TOPICAL EYE DROPS
DIURETICSINCLUDES
HYPER CARBONIC OSMOTIC inhibit carbonic anhydrase in the ANHYDRASE They by withdrawing fluid from the eye It acts AGENTS INHIBITORS
MECHANISM OF ACTION OF MECHANISM OF ACTION OF CARBONIC ANHYDRASE AGENTS HYPEROSMOTIC INHIBITORScilliary body, which prevents bicarbonate and reducing vitreous volume synthesis resulting in a fall in Na transport and aqueous flow ACETAZOLAMIDEORAL I.V IN EMERGENCY
MANNITOL I.V
DORZOLAMIDE TOPICAL EYE DRPS
SYMPATHOMIMETICSINCLUDES MECHANISM OF ACTION OF AND AGONISTS MECHANISM OF ACTION OF 2 It lowers the IOPAGONIST between and by a balance adrenoreceptors stimulation AND 1. mediated VC of the cilliary BVs will 2 AGONIST 1. It reduces aqueous humour production AGONISTS Decrease the aqueous flow
2. It increases uveoscleral outflow (secondary 2. 2 mediated effect will increase pathway for aqueous outflow 20%) trabecular meshwork drainage
CONTRAINDICATIONTARTRATE DIPIVEFRIN HCL BRIMONIDINE TOPICAL EYE DROPS TOPICAL EYE Angle-closed glaucoma DROPS
PROSTAGLANDIN ANALOGUES (F2 )EXAMPLE AND FORMLatanoprost solution: topical eye drops
MECHANISM OF ACTION1. It enhances the uveoscleral outflow of the aqueous 2. It increases blood flow to the optic nerve that may contribute in retinal neuroprotection
PARASYMPATHOMIMETICSEXAMPLE AND FORMPilocarpine HCL: topical eye drops or gel
MECHANISM OF ACTIONIt increases aqueous outflow by contracting the ciliary muscle. Which pulls the scleral spur, resulting in widening of the trabecular meshwork
SIDE EFFECTSBlurred vision and ache over the eye
DRUGS CONTRAINDICATED IN GLAUCOMATopical and systemic corticosteroids due to the possible increase in trabecular meshwork inducible glucocorticoid response (TIGR) gene expression as an assumed mechanism for outflow obstruction Strong vasodilators as nitrites as they may Increase aqueous humour formation Cycloplegic drugs as atropine