brinzolamide/brimonidine

Action and Spectrum

Actions and Spectrum:

brinzolamide and brimonidine are two medications used in the treatment of glaucoma and ocular hypertension. They work through different mechanisms to reduce intraocular pressure and prevent damage to the optic nerve.

brinzolamide is a carbonic anhydrase inhibitor that reduces the production of aqueous humor, the fluid that fills the front part of the eye. By reducing the production of aqueous humor, brinzolamide decreases intraocular pressure. It is used as eye drops and is typically administered two to three times a day.

brimonidine is an alpha-2 adrenergic agonist that reduces the production of aqueous humor and increases the drainage of aqueous humor. It also reduces the amount of fluid in the eye by constricting blood vessels in the eye.

Drug Interaction

Adverse Reaction

Frequency Defined

>10%

Xerostomia (10-30%)

Somnolence in children (50-83%)

Ocular hyperemia (10-30%)

Headache (10-30%)

Burning and stinging (10-30%)

Blurring (10-30%)

Fatigue/drowsiness (10-30%)

Foreign body sensation (10-30%)

Conjunctival follicles (10-30%)

Ocular pruritus (10-30%)

Ocular allergic reactions (10-30%)

1-10%

Blepharitis (1-5%)

Dysgeusia (5-10%)

Blurred vision (5-10%)

Black Box Warning

Black Box Warning:

The combination medication of brinzolamide and brimonidine ophthalmic has a black box warning that alerts healthcare providers and patients about the potential risk of anaphylaxis and angioedema.

Contraindication / Caution

Contraindication/Caution:

Contraindications:

• Hypersensitivity to brinzolamide, brimonidine, or any component of the medication
• Severe renal impairment (creatinine clearance less than 30 mL/min) for brinzolamide
• Severe hepatic impairment for brimonidine

Precautions:

• Cardiovascular disease: brimonidine has been associated with decreased blood pressure and heart rate, which may be problematic in patients with cardiovascular disease.
• Depression: brimonidine has been reported to cause depression and other psychiatric side effects.
• Respiratory disease: brinzolamide can worsen respiratory disease, such as chronic obstructive pulmonary disease (COPD).
• Use in pregnancy and breastfeeding: the safety of these medications during pregnancy and breastfeeding has not been established.

Pregnancy / Lactation

Pregnancy warnings:   

Pregnancy category: C

Lactation: Excreted into human milk is unknown

Pregnancy Categories:     

Category A: Studies that were well-controlled and met expectations revealed no risk to the fetus in either the first or second trimester.

Category B: There were lack of studies on pregnant women and no evidence of risk to the foetus in animal experiments.

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.

Category D: adequate data available with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.

Category N: There is no data available for the drug under this category

Pharmacology

Pharmacology:

Brinzolamide is a carbonic anhydrase inhibitor that works by decreasing the production of aqueous humor, the fluid that fills the eye. By reducing the production of aqueous humor, brinzolamide can lower the pressure inside the eye and help to prevent damage to the optic nerve.

Brimonidine is an alpha-2 adrenergic agonist that works by reducing the production of aqueous humor and increasing the outflow of fluid from the eye. This helps to further lower the pressure inside the eye and protect the optic nerve.

Pharmacodynamics:

When used in combination, brinzolamide and brimonidine can provide a synergistic effect and further reduce the pressure inside the eye. This can help to better control the symptoms of glaucoma and prevent further damage to the optic nerve.

Pharmacokinetics:

Absorption

brinzolamide and brimonidine are typically administered as eye drops, which are absorbed into the eye. The amount of medication absorbed systemically is minimal.

Distribution

Once absorbed, brinzolamide and brimonidine are distributed throughout the eye tissues, where they exert their pharmacological effects.

Metabolism

brinzolamide is metabolized in the liver by the enzyme carbonic anhydrase, while brimonidine is metabolized in the liver and kidneys by enzymes such as catechol-O-methyltransferase (COMT). The metabolites of brinzolamide are excreted in the urine, while the metabolites of brimonidine are excreted in the urine and feces.

Elimination and Excretion

Both brinzolamide and brimonidine are eliminated primarily by the kidneys. The elimination half-life of brinzolamide is approximately 111 days, while the elimination half-life of brimonidine is approximately 2-3 hours.

Adminstartion

Administration:

brinzolamide/brimonidine is a medication that is used to treat open-angle glaucoma or ocular hypertension, which are conditions that can lead to increased pressure in the eye and eventually damage to the optic nerve.

When administering brinzolamide/brimonidine, it is important to follow the instructions provided by your healthcare provider or as directed on the medication label. Typically, one drop of the medication is applied to the affected eye(s) twice a day, with at least 12 hours between doses.

Patient Information Leaflet

Patient information leaflet

Generic Name: brinzolamide/brimonidine

Why do we use brinzolamide/brimonidine?

brinzolamide/brimonidine is a medication that is used to treat open-angle glaucoma or ocular hypertension. These are conditions that can lead to increased pressure in the eye, which can eventually cause damage to the optic nerve and lead to vision loss.

brinzolamide/brimonidine works by reducing the production of fluid in the eye and increasing the outflow of fluid, which helps to decrease the pressure inside the eye.