Dorzolamide is a medication primarily used to lower intraocular pressure in patients with open-angle glaucoma or ocular hypertension. It belongs to a class of drugs called carbonic anhydrase inhibitors. By inhibiting the enzyme carbonic anhydrase, dorzolamide reduces the production of aqueous humor in the eye, thereby decreasing intraocular pressure.

Reducing intraocular pressure is crucial in the management of conditions like glaucoma, as elevated pressure can damage the optic nerve and lead to vision loss if left untreated.

Dorzolamide (Trusopt) is a carbonic anhydrase inhibitor that is used to reduce intraocular pressure (in patients with ocular hypertension and open-angle glaucoma).

Dorzolamide Uses:

• Elevated intraocular pressure:
  • Treatment of elevated intraocular pressure (IOP) in patients with ocular hypertension or open-angle glaucoma

Dorzolamide Adult dose:

Dorzolamide dose for elevated intraocular pressure:

• Dorzolamide is a medication used to treat high pressure inside the eye, which can damage vision over time.
• When using dorzolamide eye drops for this condition, you typically put one drop in the eye that needs treatment three times a day.

Dorzolamide Dose in children:

Dorzolamide Dose for the reduction of intraocular pressure:

• When it comes to reducing high pressure in the eyes, especially in infants, children, and adolescents, the usual dose of dorzolamide eye drops is one drop in the affected eye or eyes three times a day.
• This dosage should be followed as directed by a doctor.

Pregnancy Risk Factor C

• During pregnancy, dorzolamide, a medication used for glaucoma, is categorized as Pregnancy Risk Factor C, meaning adverse effects have been seen in animal studies with systemic (whole body) administration.
• Generally, eye pressure tends to decrease during pregnancy.
• However, if stopping glaucoma treatment isn't possible due to intolerance for even small increases in eye pressure, doctors may prescribe the lowest effective dose of dorzolamide along with methods like punctual occlusion to reduce exposure to the developing fetus.

Dorzolamide use during breastfeeding:

• It's uncertain whether dorzolamide passes into breast milk.
• Due to the potential for significant adverse effects in nursing infants, the manufacturer advises considering whether to stop breastfeeding or to stop taking the medication, considering how important the treatment is for the mother's health.

Dorzolamide Dose in Kidney disease:

• For individuals with a Creatinine Clearance (CrCl) of 30 mL/minute or higher, no dosage adjustments are typically needed according to the manufacturer's instructions.
• For those with a CrCl less than 30 mL/minute, the use of dorzolamide is not recommended as it has not been studied in this population.

Dose in Liver disease:

• According to the manufacturer's labeling, there are no specific dosage adjustments provided for individuals with hepatic impairment, as studies in this population have not been conducted.
• However, it is recommended to use dorzolamide with caution in patients with hepatic impairment.
• Patients with liver problems may need closer monitoring for any potential adverse effects or changes in medication response.

Side effects of Dorzolamide:

• Dermatologic:
  • Skin Rash
• Gastrointestinal:
  • Bitter Taste
  • Fatigue
  • Headache
  • Nausea
• Genitourinary:
  • Urolithiasis
• Hypersensitivity:
  • Local Ocular Hypersensitivity Reaction
• Neuromuscular & Skeletal:
  • Weakness
• Ocular:
  • Burning Sensation Of Eyes
  • Eye Discomfort
  • Stinging Of Eyes
  • Superficial Punctate Keratitis
  • Blurred Vision
  • Conjunctivitis
  • Eyelid Irritation
  • Eye Redness
  • Lacrimation
  • Photophobia
  • Xerophthalmia
  • Iridocyclitis

Contraindications to Dorzolamide:

• If someone has a hypersensitivity (allergic reaction) to dorzolamide or any ingredient in the formulation, they should not use dorzolamide eye drops.

Warnings and precautions

Bacterial Keratitis

• Contamination of multi-dose eye drop solutions has led to bacterial keratitis, a serious eye infection.

Ocular effects

• Prolonged use of dorzolamide can cause local eye problems like conjunctivitis and lid reactions.
• These issues usually improve once the medication is stopped.
• In some cases, choroidal detachment has been observed after certain eye procedures.

Allergy to sulfonamide ("sulfa")

• Dorzolamide contains sulfonamide.
• Although it's applied to the eyes, it can still be absorbed into the body and trigger allergic reactions in people with sulfonamide allergies.
• If signs of allergy or serious reactions occur, discontinue use immediately.

Systemic effects

• Dorzolamide can be absorbed into the bloodstream, potentially causing adverse effects similar to sulfonamides.
• These effects may include blood disorders, severe skin reactions like Stevens-Johnson syndrome, liver problems, and issues with the immune system.

Corneal endothelium

• People with low corneal cell counts should use dorzolamide cautiously as they may have a higher risk of developing corneal swelling.

Hepatic impairment

• Use dorzolamide with caution if you have liver problems, as the effects in this population have not been well-studied.

Renal impairment

• Dorzolamide is not recommended for people with severe kidney impairment (Creatinine Clearance <30 mL/minute) as its effects in this group haven't been studied enough.

Dorzolamide: Drug Interaction

Note: Drug Interaction Categories:

• Risk Factor C: Monitor When Using Combination
• Risk Factor D: Consider Treatment Modification
• Risk Factor X: Avoid Concomitant Use

Monitoring parameters:

• Regular ophthalmic exams and measuring intraocular pressure (IOP) should be done periodically for individuals using dorzolamide eye drops.
• This helps monitor the effectiveness of the treatment and ensures the health of the eyes.
• Ophthalmic exams can detect any changes or issues with vision or eye health, while measuring IOP helps assess the pressure inside the eyes, which is crucial for managing conditions like glaucoma.

How to administer Dorzolamide?

Using Multiple Eye Drops:

• If you're using more than one type of eye drop, make sure to give them at least 5 minutes apart. This helps each medication work properly without interfering with each other.

Contact Lens:

• Before putting in your eye drops, take out your contact lenses. Wait for about 15 minutes after using the drops before putting them back in. This gives the medication enough time to work without being absorbed by the contacts.

Avoiding Contamination:

• When putting in eye drops, be careful not to let the tip of the bottle touch your eye or anything around it. This helps prevent contamination and keeps your eyes safe.

Mechanism of action of Dorzolamide:

• Dorzolamide works by temporarily blocking the action of an enzyme called carbonic anhydrase.
• This inhibition reduces the secretion of hydrogen ions in the kidney's tubules.
• As a result, the body excretes more sodium, potassium, bicarbonate, and water through the kidneys, which helps lower the production of aqueous humor in the eye.
• Additionally, dorzolamide inhibits carbonic anhydrase in the central nervous system, which helps to slow down abnormal and excessive nerve impulses from the CNS neurons.
• This combined action helps to decrease intraocular pressure and manage conditions like glaucoma effectively.

Duration of Action:

• Dorzolamide's effects typically last for 8 to 12 hours.

Absorption:

• When applied to the eyes, dorzolamide can enter the bloodstream and accumulate in red blood cells (RBCs) over time due to its binding to carbonic anhydrase-II (CA-II).

Distribution:

• Dorzolamide is distributed throughout the body, particularly accumulating in red blood cells during prolonged use.

Protein Binding:

• Approximately 33% of dorzolamide binds to proteins in the bloodstream.

Metabolism:

• Dorzolamide is metabolized into a less potent form called N-desethyl metabolite.

Half-life Elimination:

• The terminal half-life of dorzolamide in red blood cells is approximately 147 days. It washes out of red blood cells non-linearly, with an initial rapid decline followed by a slower elimination phase, resulting in an overall half-life of about 4 months.

Excretion:

• Dorzolamide and its metabolite (N-desethyl) are eliminated primarily through urine, with some of the drug being excreted unchanged.

International Brands of Dorzolamide:

• Trusopt
• APO-Dorzolamide
• RIVA-Dorzolamide
• SANDOZ Dorzolamide
• Trusopt (Preservative Free)
• Apisopt
• Biodrop
• Bolano
• Ciplamide
• Citol Dorzo
• Dorsamed
• Dorsopt
• Dorzolam
• Dorzox
• Glaucotensil D
• Lamisopt
• Nodom
• Oftidor
• Sefson
• Strigdar
• Trusopt
• Xola
• Zolichek

Dorzolamide Brand Names in Pakistan: