Dorzolamide Shortage: What Providers and Prescribers Need to Know in 2026

As of 2026, dorzolamide hydrochloride ophthalmic solution 2% is not listed on the FDA's current drug shortage database. However, prescribers managing glaucoma and ocular hypertension patients are reporting localized stock-out issues at retail pharmacies — an increasingly common reality for generic ophthalmic medications. This guide is designed to help you navigate these availability challenges efficiently and minimize treatment gaps for your patients.

Current Availability Overview

Dorzolamide became available as a generic following the voluntary market withdrawal of Trusopt (Merck). Multiple generic manufacturers now produce dorzolamide 2% ophthalmic solution, which has generally improved supply resilience. The combination product dorzolamide/timolol 2%/0.5% (generic Cosopt) is similarly available from multiple sources, including a preservative-free formulation (Cosopt PF equivalent).

Localized stock-outs can still occur due to:

• Distributor-level inventory fluctuations (particularly at regional wholesalers)
• Pharmacy formulary preferences for specific generic manufacturers
• Low baseline stocking quantities for ophthalmic generics at community pharmacies
• Insurance plan restrictions limiting covered generic manufacturers

Clinical Pharmacology Reminder: Why Consistent Dosing Matters

Dorzolamide is a highly selective inhibitor of carbonic anhydrase II (CA-II), with approximately 4,000-fold greater affinity for CA-II than CA-I. By blocking CA-II in the ciliary epithelium, dorzolamide reduces secretion of bicarbonate ions, decreasing aqueous humor production and lowering intraocular pressure (IOP) by approximately 20% at steady state. Steady-state accumulation occurs in red blood cells.

IOP control in glaucoma is continuous — there is no therapeutic buffer period during which missed doses are inconsequential. When patients miss doses, IOP can rise within hours, depending on the patient's baseline secretion rate and outflow. For patients at target IOP with minimal margin, even 2-3 days without medication can represent a meaningful risk exposure.

Therapeutic Alternatives When Dorzolamide Is Unavailable

If dorzolamide is not available for a patient, the following substitutions are clinically reasonable, depending on the patient's existing regimen and medical profile:

• Brinzolamide 1% (Azopt): Direct class equivalent (CAI). Suspension formulation with pH closer to tear film, resulting in less ocular irritation in most patients. TID dosing. Also a sulfonamide — avoid in sulfa-allergic patients. May be preferred for patients with documented corneal disease.
• Dorzolamide/timolol 2%/0.5% (generic Cosopt): Appropriate if patient is not already on a topical beta-blocker and has no contraindications (asthma, COPD, bradycardia, second/third-degree AV block, decompensated heart failure). BID dosing may improve adherence.
• Brinzolamide/brimonidine (Simbrinza): Fixed-combination CAI + alpha-agonist; useful for patients who cannot tolerate beta-blockers. TID dosing; CNS side effects possible with brimonidine.
• Prostaglandin analog (latanoprost, bimatoprost, travoprost): Appropriate if patient is not already on a PGA and this is an opportunity to simplify therapy. QD dosing; stronger IOP reduction (~25-30%) than dorzolamide alone.

Drug Interactions and Contraindications to Review at Transition

When transitioning dorzolamide patients to a beta-blocker-containing alternative, confirm the following contraindications are absent:

• Bronchial asthma or severe COPD
• Sinus bradycardia, second- or third-degree AV block, overt cardiac failure
• Current use of systemic beta-blockers or calcium channel blockers (additive hypotensive/bradycardic effect)

For dorzolamide itself, the key interactions to document before prescribing include:

• Concurrent oral carbonic anhydrase inhibitors (acetazolamide, methazolamide) — concomitant use is contraindicated due to risk of additive systemic inhibition and electrolyte disturbances
• High-dose salicylates — risk of acid-base disturbance with systemic CA inhibition
• Severe renal impairment (CrCl <30 mL/min) — dorzolamide and its metabolite are renally excreted; use is not recommended in severe renal impairment

Communicating Availability Challenges to Patients

When counseling patients on localized availability issues, it helps to be specific and action-oriented. Vague reassurances can lead patients to delay seeking their medication. Effective talking points include:

• "There's no nationwide shortage, but some local pharmacies are low on stock. I want you to call us right away if you can't fill it — don't wait until you're out."
• "A service called medfinder can call pharmacies near you to find where it's in stock — it's worth using if your usual pharmacy doesn't have it."
• "If you run out before finding it, call us immediately. We have alternatives we can prescribe in the short term."

Helping Your Patients Find Dorzolamide

For practices looking to streamline the process of helping patients locate medications, medfinder for providers is a concierge service that calls pharmacies on behalf of your patients. You can recommend it as a patient resource, or read our guide to helping patients find dorzolamide in stock.