The generic name for the prescription eye drop medication dorzolamide is dorzolamide hydrochloride. This carbonic anhydrase inhibitor is primarily used to treat elevated intraocular pressure (IOP) in people with ocular hypertension or open-angle glaucoma. While the brand name Trusopt, which contained dorzolamide as its sole active ingredient, has been discontinued, the drug remains available in generic form. It is also combined with other medications, such as timolol, in other brand-name eye drops like Cosopt.
How Dorzolamide Works
As a carbonic anhydrase inhibitor, dorzolamide works by targeting the enzyme carbonic anhydrase, which is present in the eye's ciliary processes. By inhibiting this enzyme, the medication decreases the production of aqueous humor, the fluid inside the eye. A reduction in aqueous humor production leads to a decrease in intraocular pressure, which is crucial for managing glaucoma and preventing further damage to the optic nerve. This topical application helps achieve therapeutic levels in the eye, with minimal systemic side effects compared to oral carbonic anhydrase inhibitors.
Medical Uses and Administration
The primary purpose of dorzolamide eye drops is to lower elevated intraocular pressure. Your doctor may prescribe it as a standalone treatment or as a part of a combination therapy. Its administration requires careful adherence to a specific regimen to ensure efficacy and minimize contamination.
Administration Steps:
- Wash your hands thoroughly with soap and water before handling the eye drops.
- Tilt your head back and gently pull down the lower eyelid to form a pocket.
- Squeeze one drop into the pocket. Be careful not to let the dropper tip touch your eye or any other surface.
- Close your eye gently for 2 to 3 minutes and apply pressure to the tear duct to prevent systemic absorption and help the medication stay in the eye.
- If you are using more than one type of eye drop, wait at least five minutes before administering the next medication.
The typical dosage for the standalone dorzolamide solution is one drop in the affected eye(s) three times daily. However, the exact dosage and frequency should always be determined by a healthcare provider.
Potential Side Effects
Like all medications, dorzolamide can cause side effects. Some are common and mild, while others may be more serious, especially for individuals with underlying health conditions or drug sensitivities.
Common Side Effects:
- Ocular burning, stinging, or discomfort immediately after instillation.
- A bitter or unusual taste in the mouth after administration.
- Blurred vision.
- Sensitivity to light (photophobia).
- Dry or watery eyes.
- Itching or redness of the eye.
Serious Side Effects (Contact your doctor immediately):
- Signs of a serious allergic reaction, such as rash, hives, swelling, or difficulty breathing.
- Serious eye reactions, including severe swelling, pain, or discharge.
- Systemic effects like those associated with sulfa drugs, including fever, skin lesions, or blood problems.
- Symptoms of a kidney stone, such as back or abdominal pain.
Comparative Glaucoma Medications
Dorzolamide belongs to a class of glaucoma medications called carbonic anhydrase inhibitors (CAIs). Other options are available, and the best choice depends on the patient's specific needs and response to treatment. Here's a quick comparison with a few other common glaucoma treatments.
| Medication (Generic Name) | Class of Drug | Administration | Advantages | Considerations |
|---|---|---|---|---|
| Dorzolamide | Carbonic Anhydrase Inhibitor (Topical) | Eye drops, typically 3 times daily. | Effective at lowering IOP, local effect with fewer systemic side effects than oral CAIs. | Risk of allergic reaction, bitter taste, eye irritation. Cautious use in patients with sulfa allergy or renal impairment. |
| Brinzolamide (Azopt) | Carbonic Anhydrase Inhibitor (Topical) | Eye drops. | Similar mechanism to dorzolamide, also used for IOP reduction. | May cause blurry vision and bitter taste. Contraindicated with sulfa allergy. |
| Timolol (Timoptic) | Beta-blocker (Topical) | Eye drops, typically 2 times daily. | Well-established, effective, and often used as a first-line treatment. | Contraindicated in patients with asthma, COPD, and certain heart conditions due to systemic absorption. |
| Latanoprost (Xalatan) | Prostaglandin Analog (Topical) | Eye drops, typically once daily. | Highly effective, well-tolerated, and convenient once-daily dosing. | Can cause irreversible brown pigmentation of the iris and eyelash growth. |
Important Considerations
Because dorzolamide is a sulfonamide, it is systemically absorbed to some extent, even when applied topically. This can cause adverse reactions similar to those caused by oral sulfonamides, including rare but severe allergic reactions. Patients with a known sulfa allergy should discuss this with their doctor before using dorzolamide. The use of dorzolamide is also not recommended for patients with severe renal impairment.
It is also important to consider potential drug interactions. Concomitant use with oral carbonic anhydrase inhibitors is generally not recommended due to the potential for additive systemic effects. Patients should inform their doctor about all medications they are taking, including over-the-counter drugs and supplements.
If you wear soft contact lenses, you must remove them before applying dorzolamide eye drops. Benzalkonium chloride, a common preservative in ophthalmic solutions, can be absorbed by soft lenses. Wait at least 15 minutes after instilling the drops before reinserting your lenses.
Conclusion
Dorzolamide hydrochloride is the generic name for the active ingredient in what was formerly known as the brand-name eye drop Trusopt. As a carbonic anhydrase inhibitor, it is an effective treatment for lowering intraocular pressure in patients with glaucoma and ocular hypertension by reducing aqueous humor production. While typically well-tolerated, patients should be aware of potential side effects, especially those with sulfa allergies, and follow proper administration techniques. Regular check-ups with an ophthalmologist are necessary to monitor eye pressure and ensure the treatment's effectiveness.
For more detailed information on dorzolamide, consult the comprehensive resource provided by the U.S. National Library of Medicine: Dorzolamide Ophthalmic: MedlinePlus Drug Information.
