Nasolacrimal occlusion

Patients prescribed topical P-blockers should be counseled on the nasolacrimal occlusion technique to decrease systemic absorption. 

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. 

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

Use of nasolacrimal occlusion will increase number of patients successfully treated with longer dosage intervals. 

When topical ophthalmic drugs must be administered to patients who are pregnant, the medications should be administered at minimally effective doses and for as short a time as possible.The use of nasolacrimal occlusion (see Chapter 3) after the instillation of eye medications minimizes systemic drug absorption and should always be recommended. Patients who take medications should also be advised about the potential risks to newborns during breast-feeding (Figure 1-2). Timolol, for example, has been shown to be concentrated in breast milk. 

Zimmerman TJ, et al. Therapeutic index of pilocarpine, carba-chol, and timolol with nasolacrimal occlusion. Am J Ophthalmol 1992 114 1-7. 

Because increased susceptibility to the side effects of cyclopentolate has been reported in infents, yoimg children, and children with spastic paralysis or brain damage, use of concentrations higher than 0.5% is not recommended in these patients. The potential for systemic absorption of cyclopentolate, as of other topically appUed ocular drugs, may be reduced with nasolacrimal occlusion. 

The necessity of administering pilocarpine solutions four times daily without nasolacrimal occlusion makes this form of therapy a poor choice in patients who are likely to demonstrate poor compliance with this medication schednle. In these instances, the practitioner should... 

In patients at risk for systemic side effects from topically administered pharmacologic agents, eyelid closure and manual nasolacrimal occlusion (see Figure 3-6) are reasonable procedures to minimize nasolacrimal drainage of drug and subsequent absorption into the systemic circulation. 

In patients who are predisposed to adverse cardiovascular events, the use of tropicamide either alone or in combination with 2.5% phenylephrine provides satisfactory mydriasis while minimizing the risks of systemic complications. In addition, the use of low concentrations of drug, single applications, eyelid closure, and nasolacrimal occlusion minimizes adverse reactions in susceptible patients. Thus the combination solution made by mixing equal amounts of 1% tropicamide and 2.5% phenylephrine as previously described may have the added benefit of reducing the chances of an adverse reaction even further. 

It is always wise to advocate nasolacrimal occlusion by digital compression of the lacrimal drainage system when using phenylephrine eye-drops in patients at risk or in patients in whom higher concentrations are necessary (3). 

Ellis PP, Wu P-Y, Pfoff DS et al (1992) Effect of nasolacrimal occlusion on timolol concentrations in the aqueous humor of the human eye. J Pharm Sci 81 219-20... 

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