Aqueous suppressant

Low lOP after cataract surgery can be due to a variety of reasons, including woimd leak, cihochoroidal effusion, cyclodialysis cleft, retinal detachment, or aqueous suppression from ophthalmic medication. 

In the case of ocular hypotony and a positive Seidel s sign with a formed anterior chamber in the early postoperative period, the treatment of choice is to discontinue the steroid to encourage wound closure and avoid secondary infection. The patient should be placed on a third- or fourth-generation topical fluoroquinolone. A topical aqueous suppressant may also be used to ensure secure wound closure.The patient is asked to limit activities and is given an eye shield to wear at night. An alternative treatment may include the use of a topical antibiotic and a 24-hour pressure patch with an eye shield while sleeping. If the wound feils to seal after several days to 1 to 2 weeks, surgical repair should be considered. 

The most efficient topical medications to reduce lOP in postoperative patients are those whose mechanism involves aqueous suppression. These agents would include topical carbonic anhydrase inhibitors, apracloni-dine, brimonidine, beta-blockers, and oral carbonic anhydrase inhibitors. Prostaglandin analogues and miotics are effective in lowering the lOP postoperatively however, they may cause increased inflammation and should not be considered a first-line treatment. 

In patients who have malignant glaucoma, aqueous suppressants help lower the lOP and cycloplegics deepen the angle and may help restore normal aqueous flow. If conservative measures feil, an anterior vitrectomy is usually curative. 

In patients with history of ocular inflammation, 1% prednisolone acetate, one drop four times a day for 3 to 7 days, can be prescribed prophylactically after Nd YAG. Rarely, a patient without history of inflammation may present with flare or mild cells in the anterior chamber or CME after capsulotomy. This also should be treated with topical steroids in the same manner. Post-YAG elevated lOP can often be prevented by treating the eye with apra-clonidine (lopidine) or other aqueous suppressant topical medication. The recommended dosage is one drop applied before the capsulotomy and one drop immediately after the procedure. Because of the potential risk of a retinal break, patients should receive dilated fundus examinations postoperatively as part of the routine follow-up within 1 to 4 weeks of capsulotomy, or sooner if symptoms develop. 

In practice, it would be prudent to explain to patients that their lOP will vary during the day and night (this sets the stage for future instructions on the proper use of aqueous suppressants during times of physiologic higher aqueous production) and ensures the patient that different readings at each visit are not uncommon. 

The aqueous suppressants include the P-adrenergic antagonists, a-agonists, carbonic anhydrase inhibitors (CAIs topical and oral), and hyperosmotics (intravenous). The topical fiarms of this classification are used routinely in clinical practice. The oral and intravenous formulations are generally reserved fiar use under special circumstances. 

Carbonic Anhydrase Inhibitors. The CAls (Table 34-8) are aqueous suppressants not typically used as first-line medications in the treatment of glaucoma. 

Increased lOP in the Presence of Hyphema Traumatic hyphema may lead to an increase in lOE lOP reduction should be accomplished by aqueous suppressants. 

Treatment of lOP should concentrate on aqueous suppression, and timolol and brimonidine (or apracloni-dine) should be the mainstays of lOP management. CAIs (especially oral acetazolamide and methazolamide) are capable of promoting hemoconcentration and can induce systemic acidosis, which is known to exacerbate erythrocyte sickling. 

In most cases the treatment of these conditions involves both anti-inflammatory (typically topical corticosteroids) and antiglaucoma (typically aqueous suppressants) medications. Cycloplegics are used to prevent or manage posterior synechia, secondary neovascular glaucoma, and choroidal effusion. Miotics are typically avoided in the management of these conditions because their use... 

Schadlu R, Mans TL, Nau CB, Brubaker RF. Comparison of the efficacy of apraclonidine and brimonidine as aqueous suppressants in humans. Arch Ophthalmol 1998 116(ll) 1441-4. 

Physical and chemical properties of the three most important forms of sodium sulfate are summarized ia Table 3. The solubiUty of sodium sulfate ia water from 0 to 360°C is shown ia Figure 1 (5). The solubiUty of the NaClNa2S04-H2 0-saturated system is also shown. The aqueous solubiUty of sodium sulfate changes rapidly from 0 to 40°C, and addition of NaCl to a saturated solution of Na2S04 dramatically suppresses this solubiUty. These two effects are exploited by all manufacturers of sodium sulfate. 

The high chemical stability of pterins towards aqueous base is due to anion formation suppressing nucleophilic attack at a ring carbon atom by electrostatic repulsion. Substitution... 

Zorbax PSM packings are produced in three forms unmodified, trimethyl-silane modified, and diol modified. Modified Zorbax PSM packings are produced by chemically bonding a layer on the silica surface through siloxane bonds (Table 3.1). Silanized Zorbax PSM packings suppress adsorption effects and are the preferred choice when the mobile phase contains organic solvents. Unsilanized and diol modified Zorbax PSM packings should be used when the mobile phase consists of aqueous solvents. 

Scheme 3b). It is instructive at this point to reiterate that the furan nucleus can be used in synthesis as a progenitor for a 1,4-dicarbonyl. Whereas the action of aqueous acid on a furan is known to provide direct access to a 1,4-dicarbonyl compound, exposure of a furan to an alcohol and an acid catalyst should result in the formation of a 1,4-diketal. Indeed, when a solution of intermediate 15 in benzene is treated with excess ethylene glycol, a catalytic amount of / ara-toluenesulfonic acid, and a trace of hydroquinone at reflux, bisethylene ketal 14 is formed in a yield of 71 %. The azeotropic removal of water provides a driving force for the ketalization reaction, and the presence of a trace of hydroquinone suppresses the formation of polymeric material. Through a Finkelstein reaction,14 the action of sodium iodide on primary bromide 14 results in the formation of primary iodide 23, a substance which is then treated, in crude form, with triphenylphosphine to give crystalline phosphonium iodide 24 in a yield of 93 % from 14.

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