Multiple factors guide decisions for post-SLT management

September 1, 2006
Cheryl Guttman

San Francisco-Selective laser trabeculoplasty (SLT) is a major advance in the management of glaucoma because it safely and effectively lowers IOP without damaging or disrupting the trabecular beams.

San Francisco-Selective laser trabeculoplasty (SLT) is a major advance in the management of glaucoma because it safely and effectively lowers IOP without damaging or disrupting the trabecular beams.

However, there is emerging evidence that the postoperative medical management of inflammation in SLT patients may influence the IOP outcome. In addition, practitioners may need to make medication decisions in cases where patients need adjunctive therapy to reach their IOP goal.

For glaucoma specialist Jason Bacharach, MD, the nonsteroidal anti-inflammatory drug (NSAID) bromfenac 0.09% (Xibrom, ISTA Pharmaceuticals) has become his treatment of choice for controlling inflammation after SLT, while he often chooses the novel formulation of timolol maleate 0.5% containing potassium sorbate (Istalol, ISTA) as his first-line ancillary drop therapy when a patient does not achieve the targeted IOP goal after SLT.

"It is thought that the laser treatment induces upregulation of cytokines and recruitment of macrophages that clean out debris from the intratrabecular spaces. Those inflammatory-mediated pathways may be less affected by an NSAID, and that may translate into relatively greater IOP-lowering," Dr. Bacharach explained.

Minimizing administration

Among the ophthalmic NSAIDs available, Dr. Bacharach said he favors bromfenac because it is very well-tolerated and offers a convenient twice-a-day administration regimen. Patients are instructed to use it for 4 days after the procedure.

"Minimizing the frequency of administration enhances therapeutic compliance, and patients also find bromfenac very comfortable on instillation," he said. "I am aware that some ophthalmologists will even prescribe the anti-inflammatory medication for just 1 day postop. However, my 4-day regimen is a compromise between such a minimalist approach and the traditional use of a 7-day course of steroids."

Dr. Bacharach said he has used bromfenac after SLT in about 200 eyes. Although he has not conducted a formal study to investigate its efficacy and safety, his clinical impressions indicate that it is just as effective in controlling general ocular inflammation when those patients are compared with historical controls he treated with the corticosteroid fluorometholone four times a day for 7 days.

"I have not noted any increase in flare or cellular reaction since switching to bromfenac nor has there been any increase in patients complaining of pain," he said.

For patients who need medical therapy to achieve target IOP after SLT, mechanistic considerations also provide a partial basis for choosing a beta-blocker.

"SLT affects outflow while the IOP-lowering activity of a beta-blocker is mediated through effects on inflow," Dr. Bacharach said. "Therefore, it makes sense to combine these two modalities with their different mechanisms of action.

"Furthermore, the patients who need ancillary medical therapy for optimal IOP control after SLT are often those who are undergoing the laser procedure as a secondary measure after topical treatment with a prostaglandin analogue has failed," he said. "A beta-blocker is a rational second-step choice in that situation."

His beta-blocker of choice is Istalol for several reasons. The product is well-tolerated, approved for once-daily administration, and does not seem to increase inflammation in the perioperative period if it is started soon after SLT. In addition, compared with other beta-blockers, it offers higher penetration through the cornea to deliver more drug to its therapeutic target site. That benefit is achieved without any increase in systemic absorption that could result in an increased risk of cardiovascular or respiratory side effects.

IOP is monitored carefully after SLT, and Dr. Bacharach waits at least 1 week to evaluate the response.

"Although it can take a few months for the maximum IOP-lowering effect of SLT to be achieved, each patient is evaluated on an individual basis taking risk level into account," Dr. Bacharach concluded. "That information is used to guide my decisions about when to initiate medication after the procedure."

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