Dorzolamide

How Does Dorzolamide Work?

Dorzolamide lowers intraocular pressure by inhibiting carbonic anhydrase II (CA-II), an enzyme in the ciliary body of the eye that plays a critical role in aqueous humor production. Carbonic anhydrase catalyzes the conversion of carbon dioxide and water into bicarbonate and hydrogen ions — a reaction that drives the sodium-hydrogen exchange necessary to produce aqueous fluid. By blocking CA-II, dorzolamide reduces bicarbonate production and decreases the secretion of aqueous humor.

Dorzolamide has approximately 4,000-fold greater affinity for CA-II than for CA-I, making it highly selective. This selectivity helps minimize systemic effects, though some absorption does occur through the nasolacrimal duct. At steady state, dorzolamide lowers IOP by approximately 20%. Effects begin within about 3 hours of instillation and last approximately 8 hours, necessitating three-times-daily dosing.

Unlike prostaglandin analogs (which increase aqueous outflow) or beta-blockers (which reduce aqueous production via a different pathway), dorzolamide acts directly on the enzymatic mechanism of fluid secretion. It is often used in combination with these other classes to achieve additive IOP reduction.

How Hard Is It to Find Dorzolamide in Stock?

As of 2026, dorzolamide is not on the FDA's active drug shortage list. Multiple generic manufacturers produce dorzolamide 2% ophthalmic solution following the discontinuation of brand-name Trusopt, which generally supports supply availability. Most major pharmacy chains (CVS, Walgreens, Walmart, Costco) and mail-order pharmacies carry generic dorzolamide routinely.

However, local stock-outs do occur — particularly at smaller or independent pharmacies, or when a specific generic manufacturer experiences supply disruptions. Patients who rely on dorzolamide for glaucoma management should not wait until they're out of medication to refill. Refilling with 1-2 weeks remaining provides a buffer to find stock if your primary pharmacy is temporarily out.

If your pharmacy is out of stock, medfinder can contact pharmacies near you to find which ones have dorzolamide in stock, saving you from making multiple phone calls.

Who Can Prescribe Dorzolamide?

Dorzolamide is not a controlled substance and has no DEA scheduling requirements. Any licensed prescriber with standard prescribing authority can write a prescription for it. In practice, the following provider types most commonly prescribe and manage dorzolamide therapy:

• Ophthalmologists — primary specialists for glaucoma diagnosis and surgical management; most commonly initiate dorzolamide therapy
• Optometrists (ODs) — licensed to diagnose and prescribe for glaucoma in most U.S. states; often primary managers of stable open-angle glaucoma patients
• Primary care physicians (MD/DO) — may renew existing dorzolamide prescriptions for stable patients between specialist visits
• Nurse practitioners and physician assistants — can prescribe dorzolamide within their scope of practice, typically under supervision in ophthalmology practices

Telehealth availability is limited for initial prescriptions because glaucoma diagnosis requires in-person intraocular pressure measurement by tonometry. However, stable patients may be able to receive prescription renewals via telehealth in some states. Confirm telehealth availability with your specific provider.

Is Dorzolamide a Controlled Substance?

No. Dorzolamide is not a controlled substance. It has no DEA schedule and is not subject to any federal controlled substance restrictions. Any licensed prescriber with standard prescribing authority can write a prescription for dorzolamide without a DEA number, without using special prescription forms, and without any limitations on the number of refills.

Dorzolamide prescriptions can be transferred to any pharmacy without restriction, filled in 30- or 90-day quantities, and refilled as needed according to your doctor's instructions. There are no additional regulatory steps for patients or pharmacists beyond a standard prescription.

Common Side Effects of Dorzolamide

The most frequently reported side effects of dorzolamide are local (in or around the eye) and typically occur immediately after instillation:

• Eye burning, stinging, or discomfort (~33% of patients)
• Bitter or unusual taste (~25% of patients) — due to nasolacrimal drainage
• Superficial punctate keratitis (10-15% of patients)
• Ocular allergic reaction (~10% of patients)
• Eye redness, temporary blurred vision

Serious Side Effects

• Stevens-Johnson syndrome — rare but life-threatening skin reaction; stop medication and seek emergency care
• Systemic allergic reactions — angioedema, bronchospasm, urticaria (especially in sulfa-allergic patients)
• Bacterial keratitis (from bottle contamination)
• Choroidal detachment following filtration surgery

Final Thoughts on Dorzolamide

Dorzolamide is a well-established, affordable generic medication for the management of open-angle glaucoma and ocular hypertension. As the only topical carbonic anhydrase inhibitor available in solution form, it fills an important role in glaucoma therapy — particularly as an add-on agent for patients who need additional IOP lowering beyond their primary medication.

While the brand-name Trusopt is no longer available, the generic dorzolamide is widely stocked and cost-effective. Patients using GoodRx or SingleCare coupons can typically purchase it for $14-$15 per bottle — a significant savings from the $58 retail price. Most insurance plans cover it at low-tier copays.

If you're struggling to find dorzolamide at your pharmacy, medfinder can contact pharmacies near you to find which ones have your medication in stock — saving you time and helping ensure you never miss a critical dose of your glaucoma therapy.