Brimonidine plays versatile role in care

Newport Beach, CA-Alpha₂ adrenoceptor agonist therapy using brimonidine tartrate 0.1% with a preservative (Alphagan P 0.1% with Purite, Allergan) has a wide spectrum of uses in the management of ocular hypertension and glaucoma, said Ehsan Sadri, MD.

Adjunctive therapy

"Alpha₂ adrenoceptor agonists both reduce aqueous production and increase uveoscleral outflow and work nicely with a prostaglandin analogue that acts primarily to increase uveoscleral outflow albeit via a different mechanism [from] brimonidine," he said. "Generally, patients have an excellent, robust response with the addition of [brimonidine with a preservative] to existing prostaglandin analogue treatment in terms of IOP reduction and mitigation of progressive optic neuropathy."

Dr. Sadri added that although three-times-daily dosing is recommended in the product information for brimonidine, he usually prescribes it twice daily with good results.

Its favorable safety and tolerability profile also makes brimonidine an excellent choice for adjunctive therapy with a prostaglandin analogue. Its most common side effects include allergic conjunctivitis, oral dryness, conjunctival hyperemia, and somnolence. However, with the lower concentration of brimonidine in the newest formulation [Alphagan P 0.1%], drug exposure is reduced and so are adverse event rates. Brimonidine also has a more favorable systemic safety profile compared with timolol.

"When prescribing [brimonidine], it is important to caution patients about the potential for hyperemia, although this problem occurs less often with the branded brimonidine formulation than with generics," Dr. Sadri said. "Overall, the majority of patients experience no significant adverse events with brimonidine."

Brimonidine monotherapy

In a variety of clinical situations in which inflammation is an issue and a prostaglandin analogue is best avoided, brimonidine is a useful alternative as monotherapy.

One such commonly encountered scenario is represented by the patient who will be undergoing cataract surgery, because ongoing prostaglandin analogue treatment can increase the risk of postoperative cystoid macular edema (CME). In these patients, Dr. Sadri said he switches the IOP-lowering medication to brimonidine twice daily 1 month prior to cataract surgery and continues the alpha₂ adrenoceptor agonist for at least 90 days.

"IOP control is generally well-maintained with the switch to brimonidine, and I recently had a patient who achieved an even further IOP lowering of 1 mm Hg in one eye and 2 mm Hg in the fellow eye after [treatment was] switched from latanoprost to brimonidine," Dr. Sadri said.

He added that some clinicians will restart the prostaglandin analogue sooner after cataract surgery. However, emerging studies indicate that the risk of postoperative CME is reduced if the prostaglandin analogue is avoided for at least 90 days. Thereafter, brimonidine may be continued if the patient is doing well and appears compliant with the twice-daily dosing. However, for some patients, less is more when it comes to dosing frequency, and they do better if treatment is switched back to the prostaglandin analogue.

Other conditions in which brimonidine is preferred over a prostaglandin analogue include pseudoexfoliation glaucoma, uveitic glaucoma, and neovascular glaucoma. In addition, for patients with light irides who wish to avoid a risk of permanent prostaglandin-induced iris color change and those who develop intolerable hyperemia with prostaglandin analogue therapy, brimondine is a safe and effective option, Dr. Sadri said.

FYI

Ehsan Sadri, MDPhone: 949/642-3100
E-mail: esadrii@gmail.com

Dr. Sadri is a consultant to Allergan.