Drugs - Ocular Drugs I MYDRIATIC DRUGS 1 Phenylephrine Hydrochloride a Percentage used 2.5 5 and 10 as eye drops b Group Sympathomimetic alpha

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Unformatted text preview: Ocular Drugs I. MYDRIATIC DRUGS 1. Phenylephrine Hydrochloride a. Percentage used: 2.5%, 5% and 10% as eye drops b. Group: Sympathomimetic, alpha adrenergic agonist c. Mechanism of Action: Acts directly on alpha receptors on- • Dilator pupillae causing mydriasis • Conjunctival arterioles causing vasoconstriction and blenching of conjunctiva Its action can be reversed by 0.1% thymoxamine d. Indications: i. For dilatation of pupil for diagnostic purposes ii. For mydriasis for doing refraction iii. Before intraocular surgery iv. For confirmation of diagnosis of Horner’s syndrome e. Side effects i. Ocular- stinging , burning, maculopathy with a central scotoma (rare) results from use in aphakic patients and rebound miosis ii. Systemic: CVS – palpitation, tachycardia, cardiac arrhythmia, hypertension, headache , myocardial ischemia, stroke f. Contraindications for use: i. Hypersensitivity ii. Narrow angle glaucoma iii. Long standing insulin dependent diabetes iv. Hypertensive patients receiving reserpine or gaunethidine 2. Tropicamide a. Percentage used: 0.5% or 1.0% as eye drops b. Group: Anticholinergic, blocks effect of acetylcholine released from cholinergic nerve endings at iris sphincter and ciliary muscles Action: (i) Mydriasis (ii) Cycloplegia c. Indications: i. For dilatation of pupil for diagnostic purposes ii. For achieving mydriasis and cycloplegia for doing refraction (retinoscopy) iii. Before intraocular surgery and post operatively for causing mydriasis and cycloplegia and to prevent synechiae formation iv. Uveitis (to prevent formation of posterior synechiae and achieving mydriasis/ cycloplegia) v. For provocative test for angle closure glaucoma It is short acting, action last for 6-8 hours d. Side effects (i) are rare; its safe for use in cardiac and hypertensive patients e. Contraindications for use: i. Narrow angle glaucoma 3. Atropine Sulphate a. Percentage used: 0.5% and 1% as eye drops; and 1% eye ointment b. Group: Parasympatholytic (anticholinergic) c. Mechanism of Action: • Blocks response of sphincter and ciliary muscles to cholinergic stimulation causing mydriasis and cycloplegia • It is strongest mydriatic • Mydriatic effect begins in 30 min, last 7 -10 days; Cycloplegic effect begins in 60 – 90 min, last 7 -10 days d. Indications: i. Cycloplegic refraction (usually in children below the age of five years) ii. Uveitis/ Iridocyclitis iii. Penalisation ,for treatment of amblyopia (alternative to occlusion therapy) e. Side effects: (A) Ocular:...
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This note was uploaded on 12/24/2011 for the course STEP 1 taught by Professor Dr.aslam during the Fall '11 term at Montgomery College.

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Drugs - Ocular Drugs I MYDRIATIC DRUGS 1 Phenylephrine Hydrochloride a Percentage used 2.5 5 and 10 as eye drops b Group Sympathomimetic alpha

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