Common Drugs Use in Common Drugs Use in Ophthalmology Ophthalmology Rungroj Lertvithayasakul, MD Rungroj Lertvithayasakul, MD Varintorn Chuckpaiwong, MD Varintorn Chuckpaiwong, MD Department of Ophthalmology, Ramathibodi Hospital Department of Ophthalmology, Ramathibodi Hospital School of Medicine, Mahidol University School of Medicine, Mahidol University , , y y
Route of Administration Route of Administration Route of Administration Route of Administration � Local Local • Topical Topical • Intravitreous Intravitreous • Subconjunctival Subconjunctival • Subtenon Subtenon • Retrobulbar Retrobulbar • Intracameral Intracameral � Systemic Systemic y Blood aqueous barrier Blood aqueous barrier Blood retinal barrier Blood retinal barrier Blood retinal barrier Blood retinal barrier
Eyedrops Eyedrops Eyedrops Eyedrops 50 µl per drop • Only Only 20 20 % of the administered % of the administered drugs is retained drugs is retained • One drop is enough. One drop is enough. p p g g Volume of fluid held by cul-de-sac 7 – 10 µl
Drug eliminating mechanisms Drug eliminating mechanisms Drug eliminating mechanisms Drug eliminating mechanisms Lacrimal gland Lacrimal gland Tear production: Tear production: 1 1. .2 2 µl /min µl /min Turn over rate 16 % per min Remaining 4 min : 50 % 10 min : 17 % Nasal cavity Nasal cavity Nasal cavity Nasal cavity cm 2 Surface area of Surface area of 150 150 - - 200 200 cm ( ( 13 13 times of conjunctiva ) times of conjunctiva ) 200 200 times of cornea times of cornea
Drug eliminating mechanisms Drug eliminating mechanisms Drug eliminating mechanisms Drug eliminating mechanisms If the drug is If the drug is Dilution of drug Dilution of drug irritating to the eye irritating to the eye tat g to t e eye tat g to t e eye O e Overflow drainage O e Overflow drainage o o d a age d a age
Improve ocular and decrease systemic Improve ocular and decrease systemic absorption absorption � Digital pressure at medial canthal Digital pressure at medial canthal area area � Keep eyes closed for Keep eyes closed for 5 p p y y 5 min after min after taking drops taking drops � Wait Wait 10 W it W it 10 10 10 minutes between drops minutes between drops i i t t b t b t d d � Frequency ~ duration of action Frequency ~ duration of action � Order of using ~ pH Order of using ~ pH
Drug Penetration Drug Penetration Precorneal area Precorneal area Cornea Cornea Anterior Segment Anterior Segment Aqueous Humor Aqueous Humor
Drug Penetration Drug Penetration Drug Penetration Drug Penetration Factors that determine the amount of medication Factors that determine the amount of medication to penetrate the cornea to penetrate the cornea • Drug concentration Drug concentration • Viscosity • Viscosity Viscosity Viscosity • Lipid/water solubility Lipid/water solubility • pH pH H • Surfactants Surfactants • Reflex tearing Reflex tearing • Preservative Preservative
Form Form Form Form � Solution and suspension Solution and suspension � Ointment Oi t Oi t Ointment t t � Gel Gel
Solution and Suspension Solution and Suspension Solution and Suspension Solution and Suspension Most commonly used Most commonly used y Advantages Advantages - Easily instilled Easily instilled Easily instilled Easily instilled - Less interfere to vision Less interfere to vision - Fewer potential complications Fewer potential complications Fewer potential complications Fewer potential complications Disadvantages Disadvantages Disadvantages Disadvantages - Short ocular contact time Short ocular contact time - Imprecise and inconsistent delivery Imprecise and inconsistent delivery Imprecise and inconsistent delivery Imprecise and inconsistent delivery - Frequent contamination Frequent contamination - Possibilities of ocular injury with the dropper tip P Possibilities of ocular injury with the dropper tip P ibiliti ibiliti f f l l i j i j ith th ith th d d ti ti
Suspensions Suspensions Suspensions Suspensions Must be re Must be re- -suspended by shaking to provide suspended by shaking to provide an accurate dosage of drug an accurate dosage of drug g g g g
Ointment Ointment Ointment Ointment � Consist of petrolatum and mineral oil Consist of petrolatum and mineral oil � Increase contact time � Increase contact time Increase contact time Increase contact time � Disturb vision Disturb vision
Gel Gel Gel Gel � Polymer Polymer- -based aqueous gels based aqueous gels � Drug release occurs by diffusion and by erosion Drug release occurs by diffusion and by erosion of the gel surface of the gel surface f th f th l l f f
Techniques of Instillation Techniques of Instillation Techniques of Instillation Techniques of Instillation Eye ointment Eye drop Eye ointment
Packaging Packaging Packaging Packaging The outer surface The outer surface dimensions of the tip dimensions of the tip affects drop size affects drop size p
Packaging Packaging Packaging Packaging Standard colors for drug labeling and bottle cap Standard colors for drug labeling and bottle cap g g g g p p Yellow Yellow, Yellow Yellow Blue , Blue Blue Blue B blocker B blocker B blocker B blocker Red Red Mydriatics and cycloplegics Mydriatics and cycloplegics Green Green Miotics Miotics Orange Orange Carbonic anhydrase inhibitors Carbonic anhydrase inhibitors Brown or tan Brown or tan Anti Anti- -infective agents infective agents Gray Gray Gray Gray NSAIDS NSAIDS NSAIDS NSAIDS Pink Pink Steroids Steroids
Commonly used drugs Commonly used drugs
Anesthesia Anesthesia Anesthesia Anesthesia Topical T Topical T i i l l � Cornea, conjunctiva Cornea, conjunctiva � Irritate Irritate 15 15 sec sec � Duration Duration 15 15 min min � For FB removal, IOP measurement, etc. For FB removal, IOP measurement, etc. � Complications : toxic to epithelium � Complications : toxic to epithelium Complications : toxic to epithelium Complications : toxic to epithelium Tetracaine hydrochloride (Tetracaine) 0.5% Tetracaine hydrochloride (Tetracaine) Tetracaine hydrochloride (Tetracaine) Tetracaine hydrochloride (Tetracaine) 0 5% Benoxinate hydrochloride (Novesine) Benoxinate hydrochloride (Novesine) 0. .4 4% %
Anesthesia Anesthesia Anesthesia Anesthesia Local Local � Including akinesia Including akinesia g � For surgery For surgery � Complications: overdose, systemic absorption Complications: overdose systemic absorption Complications: overdose systemic absorption Complications: overdose, systemic absorption (respiratory distress, seizure) (respiratory distress, seizure) Lidocaine hydrochloride (Xylocaine) Lidocaine hydrochloride (Xylocaine) 1- -2 2 % % 1 1- -2 2 hr hr Bupivacaine hydrochloride (Marcaine) Bupivacaine hydrochloride (Marcaine) 0. .25 25- -0 0. .5 5% % 5- -7 7 hr hr
Mydriatics Mydriatics y I. Sympathomimetics I. Sympathomimetics � Stimulate dilator muscle Stimulate dilator muscle � Complications: AACG, vasoconstriction Complications: AACG, vasoconstriction � For retinal examination, surgery For retinal examination surgery For retinal examination surgery For retinal examination, surgery Phenylephrine hydrochloride (Neosynephrine) Phenylephrine hydrochloride (Neosynephrine) 10 10% % 2 2- -3 3 hr hr
Mydriatics Mydriatics Mydriatics Mydriatics II Parasympatholytics / Cycloplegics II Parasympatholytics / Cycloplegics II. Parasympatholytics / Cycloplegics II. Parasympatholytics / Cycloplegics � Inhibit constrictor m.and ciliary m. contraction Inhibit constrictor m.and ciliary m. contraction � Complications: AACG, flushing Complications: AACG, flushing � For ciliary spasm, refraction in children, retinal For ciliary spasm, refraction in children, retinal y p y p exam exam Atropine sulfate 1% Atropine sulfate % 2 2 wk wk Scopolamine hydrobromide Scopolamine hydrobromide 0. p p y y .25 25% % 3 3- -5 5 d Homatropine hydrobromide Homatropine hydrobromide 1- -2 2% % 1 1- -3 3 d Cyclopentolate hydrochloride (Cyclogyl) Cyclopentolate hydrochloride (Cyclogyl) 1% y y p p y y ( y ( y gy ) gy ) % % 24 24 hr hr Tropicamide (Mydriacyl) Tropicamide (Mydriacyl) 0. .5 5- -1 1% % 4 4- -5 5 hr hr
Mydriatics and Cycloplegics Mydriatics and Cycloplegics � Atropine sulfate At At Atropine sulfate i i lf t lf t � Cyclopentolate HCl Cyclopentolate HCl Cyclopentolate HCl Cyclopentolate HCl � Tropicamide � Tropicamide Tropicamide Tropicamide � Phenylephrine HCl Phenylephrine HCl y p y p
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