Intraocular pressure dexamethasone

The effects of topical dexamethasone on intraocular pressure have been compared with those of fluorometho-lone (SEDA-22, 446 66). The ocular hypertensive response to topical dexamethasone in children occurs more often, more severely, and more rapidly than that reported in adults. It should be avoided in children if possible and it is desirable to monitor the intraocular pressure when it is being used. Fluorometholone may be more acceptable. 

Glucocorticoids that have been used for local ophthalmic treatment include medrysone, fluorometholone, tetrahy-droxytriamcinolone, and clobetasone. Loteprednol etabo-nate 0.5% increases intraocular pressure less than dexamethasone. Studies on animal models of uveitis and two randomized double-masked trials showed that loteprednol etabonate 0.5% was less potent than dexamethasone, prednisolone acetate 1%, or fluorometholone, which may partly explain the improved toxicity profile of loteprednol etabonate (429). 

N. Bodor, N. Bodor, and W.-M. Wu, A comparison of intraocular pressure elevating activity of loteprednol etabonate and dexamethasone in rabbits, Curr. Eye Res. 11 525 (1992). 

Figure 12-3 Weekly intraocular pressure responses of eyes treated with medrysone 1%, fluorometholone 0.1%, and dexamethasone phosphate 0.1%. Each point represents a mean value (mm Hg) of 12 eyes. (Reprinted with permission from Mindel JS, Tovitian HO, Smith H, et al. Comparative ocular pressure elevations of topical corticosteroids. Arch Ophthalmol 1980 98 1578. Copyright 1980, American Medical Association.)...

A combination of topically applied Zn/DFO and dexamethasone, by virtue of their additive inhibitory effects on free radical formation and inflammation, reduced nitrogen mustard-induced injury to ocular anterior segment stmctures. Furthermore, the combination treatment of Zn/DFO and dexamethasone resulted in a speedier comeal reepithelization, less-severe comeal neovascularization, and the intraocular pressure was not as severely elevated as in the saline or the Zn/DFO- or dexamethasone-alone groups (Morad et al., 2005). 

The implant, which consisted of a 5-mg drug core surrounded by ethylene vinyl acetate and polyvinyl alcohol, was inserted through the pars plana after pars plana vitrectomy and lensectomy. The device was well tolerated and the patient s eye remained quiet and did not require any supplemental local corticosteroids. The visual acuity remained at 20/400 in the left eye and the intraocular pressure remained normal. In contrast, the patient had two episodes of recurrent anterior segment inflammation in the right eye, despite intensive topical steroids. After 10 months, the intraocular inflammation recurred in the patient s left eye, presumably because the device and surrounding tissues had become depleted of dexamethasone. 

Fig. 2. Familial distribution of intraocular pressure following application of dexamethasone. (After Armaly, M. F, Ann. N.Y. Acad. Sci., 152, 861, 1968.)...

Like fluorometholone, medrysone is a synthetic derivative of progesterone. As compared with prednisolone, dexamethasone, and fluorometholone, medrysone exhibits limited corneal penetration and a lower affinity for glucocorticoid receptors. In clinical use it appears to be the weakest of the available ophthalmic steroids. Medrysone can be useful for superficial ocular inflammations, including allergic and atopic conjunctivitis, but intraocular inflammatory conditions generally do not respond. Clinical experience with medrysone has also indicated that it is less likely to cause a significant rise in lOP. However, caution needs to be exercised in patients known to respond to steroids with a rise in lOP (so-called steroid responders), because pressure increases can lead to ocular damage. 

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