Brinzolamide dosing

Radiolabeled studies in rats demonstrated highest exposure to radioactivity from an i.v. C-brinzolamide dose in tissues containing high CA concentrations. These included liver, kidneys, spleen, lungs and salivary glands. Radioactivity concentrations in fat, nerve, skeletal muscle, skin, eyes and testes were low. Experiments in pregnant and lactating rats demonstrated transfer of radioactivity across the placental barrier and secretion of low concentrations in milk. 

Brinzolamide is well absorbed following oral dosing with absolute bioavailability in rats of about 70% from a 20 mg/kg dose. It was also found to be well absorbed in man. Due to saturable binding to carbonic... 

Studies in rabbits, monkeys and humans showed brinzolamide to be absorbed into the systemic circulation following topical ocular administration. Substantial levels (several micrograms per mL in whole blood) were achieved upon long term repeated dosing. 

TOPAMAX, a sulfamate-substituted monosaccharide approved for use as an antiepileptic drug at oral doses of up to 400 mg per day, exhibits carbonic anhydrase inhibition activity [15]. A 21-month dietary study in mice with TOPAMAX resulted in increased incidence of bladder tumors similar to those observed in the mouse carcinogenicity bioassay with brinzolamide at two years. 

Brinzolamide, a heterocyclic sulfonamide, is a topical CAI suspension that has a high affinity for the carbonic anhydrase II isoenzyme. Because the ocular hypotensive effect of the drug is equivalent whether dosed twice or three times daily, brinzolamide 1% may be administered twice daily. 

Both brinzolamide and dorzolamide exhibit similar taste abnormalities. A single case report of the development of metabolic acidosis from topical brinzolamide has been described after twice-daily dosing. Other adverse events are negligible for brinzolamide except for some blurring of vision, attributable to its suspension vehicle. 

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