Douglas J. Rhee, MD

G. SYMPATHOMIMETIC 1 (PURPLE TOP):Mechanism of Action: In ciliary body, the response is variable (beta stimulation increases aqueous production, but alpha stimulationdecreases aqueous production); in trabecular meshwork, beta stimulation causes increased trabecular outflow and increased uveoscleraloutflow; overall effect lowers IOP.Side Effects:Local: Cystoid macular edema in aphakia (more likely with epinephrine than dipivefrin), mydriasis, rebound hyperemia, blurredvision, adenochrome deposits, allergic blepharoconjunctivitis.Systemic: Tachycardia/ectopy, hypertension, headache.Contraindications: Narrow angles, aphakia, pseudophakia, soft lenses, hypertension, cardiac disease.Drug Trade Concentration Usual Dose Notesdipivefrin Propine, Dipivefrin HCl Soln, 0.1% BID Prodrug of epinephrine; when initiatingtherapy, full effect of drug is seen 2–3months laterepinephrine Epifrin Soln, 0.5, 1, 2% BID Mixed alpha and beta agonist1 For listing of preservatives of antiglaucoma medications, refer to Appendix 5.Antiglaucoma Agents 63