Brimonidine Tartrate Ophthalmic Solution, 0.2% is a relatively selective alpha-2 adrenergic agonist for ophthalmic use. The chemical name of brimonidine tartrate is 5-bromo-6 (2-imidazolidinylideneamino) quinoxaline L-tartrate. It is a white to slightly yellowish powder. In solution, brimonidine tartrate has a clear, greenish-yellow color. It has a molecular weight of 442.24 as the tartrate salt and is water soluble (34 mg/mL).
Brimonidine Tartrate Ophthalmic Solution, 0.2% is a sterile ophthalmic solution.
Each mL of Brimonidine Tartrate Solution contains:
ACTIVE: Brimonidine Tartrate 2 mg (equivalent to 1.32 mg as brimonidine free base).
PRESERVATIVE: Benzalkonium Chloride (0.05 mg)
INACTIVES: Citric Acid, Polyvinyl Alcohol, Sodium Chloride, Sodium Citrate; Hydrochloric Acid and/or Sodium Hydroxide may be added to adjust pH (5.6 to 6.6), and Water for Injection.
Mechanism of Action
Brimonidine Tartrate Ophthalmic Solution is an alpha adrenergic receptor agonist. It has a peak ocular hypotensive effect occurring at two hours post-dosing. Fluorophotometric studies in animals and humans suggest that brimonidine tartrate has a dual mechanism of action by reducing aqueous humor production and increasing uveoscleral outflow
After ocular administration of a 0.2% solution, plasma concentrations peaked within 1 to 4 hours and declined with a systemic half-life of approximately 3 hours. In humans, systemic metabolism of brimonidine is extensive. It is metabolized primarily by the liver. Urinary excretion is the major route of elimination of the drug and its metabolites. Approximately 87% of an orally administered radioactive dose was eliminated within 120 hours, with 74% found in the urine.
Elevated IOP presents a major risk factor in glaucomatous field loss. The higher the level of IOP, the greater the likelihood of optic nerve damage and visual field loss. Brimonidine Tartrate Ophthalmic Solution has the action of lowering intraocular pressure with minimal effect on cardiovascular and pulmonary parameters.
In comparative clinical studies with timolol 0.5%, lasting up to one year, the IOP lowering effect of Brimonidine Tartrate Ophthalmic Solution was approximately 4-6 mm Hg compared with approximately 6 mm Hg for timolol. In these studies, both patient groups were dosed BID; however, due to the duration of action of Brimonidine Tartrate Ophthalmic Solution, it is recommended that Brimonidine Tartrate Ophthalmic Solution be dosed TID. Eight percent of subjects were discontinued from studies due to inadequately controlled intraocular pressure, which in 30% of these patients occurred during the first month of therapy. Approximately 20% were discontinued due to adverse experiences.Read More