Subconjunctival administration route

Local or topical administration of amphotericin has been used with success. Mycotic corneal ulcers and keratitis can be cured with topical drops as well as by direct subconjunctival injection. Fungal arthritis has been treated with adjunctive local injection directly into the joint. Candiduria responds to bladder irrigation with amphotericin B, and this route has been shown to produce no significant systemic toxicity. 

Probably the greatest clinical benefit associated with the subconjunctival route of drug administration is in the treatment of severe corneal disease, such as bacterial ulcers. Much higher concentrations of antibiotics can be achieved in the affected corneal tissues with subconjunctival... 

Periocular injection of steroids should be reserved for those situations requiring an anti-inflammatory effect greater than that obtainable with topical or systemic administration. Concurrent administration of steroid by both topical and subconjunctival routes does appear to produce an additive therapeutic effect in severe inflammations, but periocular injection alone does not necessarily result in greater anti-inflammatory effects.These fects suggest that topical administration should be the primary route of steroid therapy for anterior segment inflammations. Table 12-3 compares the achmitages and disachmitages of the three routes of steroid administration. 

The ocular side effects of corticosteroids are many and are related to the route of administration. The most common concerns are increased intraocular pressure (lOP) and cataracts, but delayed epithelial woimd healing and increased risk of infection due to immime modulation and decreased tear lysozyme levels are issues for the cornea. Changes to other ocular tissues have been noted (subconjunctival hemorrhages, blue sclera, eyelid hyperemia and edema, retinal emboUc events, central serous choroidopathy) and neurologic compUcations reported (diplopia, nerve palsies, intracranial hypertension) (see Appendix 35-1). 

Subconjunctival injection of dmg should not be used as a sole route of medication but should be used to supplement topical administration in anterior segment disease and parenteral administration in posterior segment disease. 

Classical pharmacokinetic models of systemicaUy administered drugs (see Chapter 1) do not fuUy apply to many ophthalmic drugs. Most ophthalmic medications are formulated to be apphed topically or may be injected by subconjunctival, sub-Tenon s, and retrobulbar routes (Figure 63-1 and Table 63-1). Although similar principles of absorption, distribution, metabolism, and excretion determine drug disposition in the eye, these alternative routes of drug administration introduce other variables in compartmental analysis. 

The routes of ocular drug administration (Figure 16.2 and Table 16.1) can be classified as conventional routes or novel routes. The conventional routes include the topical and systemic administration, while the novel routes include the subconjunctival, the subtenon, the retrobullar, the peribulbar and the intracameral [13]. 

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