Brimonidine and brinzolamide for treating glaucoma and ocular hypertension; a safety evaluation.

INTRODUCTION: Brimonidine tartrate and brinzolamide eye drops are often used as third and fourth line treatment options to reduce intraocular pressure (IOP) in the management of glaucoma and ocular hypertension. Better tolerated, more effective topical agents requiring once daily instillation including prostaglandin analogues and beta-blockers usually are preferred as initial therapy, unless there are contraindications. Brimonidine and brinzolamide are often required owing to progressive glaucoma or intolerances to or ineffectiveness of front-line agents. Areas covered: We review the safety of formulations containing brimonidine tartrate and/or brinzolamide. Safety considerations for these agents in higher risk populations are highlighted. Expert opinion: Each class of ocular hypotensive eye drop has a unique set of possible side effects. Brimonidine might have neuro-protective capabilities and offer reasonable IOP control, but its use is limited by a relatively high rate of ocular allergy, hyperemia and discomfort. Brinzolamide is generally well tolerated, but often lacks efficacy. The introduction of brimonidine/brinzolamide fixed combination suspension improves adherence (by simplifying the medical regimen) and reduces preservative load on the ocular surface. New drug delivery systems incorporating brimonidine and brinzolamide are in development and promise to improve the safety profiles of both drugs.

Investigational and experimental drugs for intraocular pressure reduction in ocular hypertension and glaucoma.

INTRODUCTION: Intraocular pressure (IOP) is the most significant modifiable risk factor to prevent onset or progression of glaucoma. Glaucoma prevalence continues to increase, emphasizing the need for improved ocular hypotensive treatment options. To try to improve on both tolerance and IOP control of currently available therapies, different receptors or mechanisms are being explored to reduce IOP more effectively and to improve tolerance. AREAS COVERED: We review synthetic topical and oral drugs in early development for the management of ocular hypertension and glaucoma. EXPERT OPINION: New therapeutic agents for IOP control have been discovered; some appear to be reasonably tolerated. IOP reduction may be limited with some agents, but other benefits although unproven may compensate for this, such as less ocular surface disease, enhanced neuro-protection or increased ocular blood flow. Further product development promises improved treatment options for ocular hypertensives and glaucoma sufferers.

Emerging drugs to treat glaucoma: targeting prostaglandin F and E receptors.

INTRODUCTION: Commercially available prostaglandin analogues (PGAs) activate the prostaglandin F receptor (FP) reducing intraocular pressure (IOP), thereby stabilizing glaucomatous optic neuropathy. Poor adherence with eye drops and intolerance impact treatment success. AREAS COVERED: We review developments in drug formulation and delivery, including punctal plugs, topical ring inserts, subconjunctival injections and inserts, and intraocular inserts. We also outline research into new fixed dose combinations that include prostaglandin analogues and preservative-free versions of established agents. EXPERT OPINION: Glaucoma is a chronic, usually progressive disease that causes irreversible visual loss. As its prevalence increases exponentially with age, it has significant implications as the population ages. Health resources need to meet increased demand for glaucoma management resources, including monitoring and treating glaucoma suspects and patients and supporting those who have suffered visual disability. Several promising therapies are under investigation. Sustained-release prostaglandin analogues using alternate delivery methods are encouraging. Delivery routes may be more invasive than topical drops. Nanotechnological-release delivery of prostaglandin analogues could lower IOP effectively. Approaches like this would eliminate many of the adherence issues associated with daily topical PGA eye drop use.