Nasolacrimal duct, occlusion

Use of nasolacrimal occlusion decreases systemic absorption up to 60% and may increase ocular bioavailability of the drug. After instillation of the eye drop, the patient should close the eye and press a finger gently against the nasolacrimal duct (tear duct) for 2 to 3 minutes. 

Excess adrenaline may pass down the nasolacrimal duct and cause vasoconstriction and dryness in the nose. Oxidation products may be deposited in the duct causing obstruction (SED VIII, p. 305). Epinephrine therapy may cause occlusion of all 4 puncta with resultant epiphora it may also be related to the development of localized conjunctival deposits. The hydrochloride probably provides a wider margin of safety as far as comeal and conjunctival deposits are concerned. 

Nasolacrimal occlusion The closing of the tear duct by application... 

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