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Top 5 Topical Carbonic Anhydrase Inhibitors for Dogs in Canada — 2025 Veterinary Guide to Trusopt, Azopt, Cosopt and Generics for Safer IOP Control

Published on Thursday, August 21, 2025

Topical carbonic anhydrase inhibitors (CAIs) lower intraocular pressure (IOP) by inhibiting the carbonic anhydrase enzyme in the eye and are applied directly to the canine eye. Common veterinary formulations include dorzolamide and brinzolamide, used alone or combined with other classes such as beta-blockers. This category is appealing to Canadian pet owners and veterinarians because topical CAIs offer targeted pressure reduction with reduced systemic exposure, multiple branded and generic options for cost flexibility, and formulations that support convenient at-home dosing. In Canada, demand is driven by greater awareness of early glaucoma detection, increasing access to veterinary ophthalmology via regional clinics and telemedicine consultations, and price sensitivity that favors high-quality generics and combination products when appropriate.

Quick Menu

1. Best Branded Dorzolamide (canine use)

2. Best Brinzolamide Suspension (canine)

3. Best Fixed-Combination Therapy (canine glaucoma)

4. Best Generic Dorzolamide (affordable canine)

5. Best Generic Brinzolamide (affordable suspension)

1
BEST BRANDED DORZOLAMIDE (CANINE USE)

Trusopt (Dorzolamide) 2% Ophthalmic Solution

Trusopt (Dorzolamide) 2% Ophthalmic Solution

Trusopt is the reference-brand dorzolamide 2% aqueous solution with a long clinical track record and predictable topical carbonic anhydrase inhibition that veterinarians rely on for dogs. Its sterile solution formulation is easy to instill and generally causes less transient visual disturbance than suspensions, making it a practical and cost-effective branded choice compared with combination products and some suspension-based alternatives.

4.2
★★★★☆
  • Rapid IOP drop

  • Low irritation

  • Rapid IOP drop

  • Low irritation

Review Summary

85%

"Most long‑term users report reliable intraocular pressure reduction in dogs, though many note a transient stinging/burning on application; overall effective but often pricier than generics."

  • Clinic staple, woof!

  • Dorzolamide 2% topical solution that lowers intraocular pressure by inhibiting carbonic anhydrase.

  • Clinic staple, woof!

  • Dorzolamide 2% topical solution that lowers intraocular pressure by inhibiting carbonic anhydrase.

Increased Safety & Security

Time-Saving Convenience

Trusopt is the reference-brand dorzolamide 2% aqueous solution with a long clinical track record and predictable topical carbonic anhydrase inhibition that veterinarians rely on for dogs. Its sterile solution formulation is easy to instill and generally causes less transient visual disturbance than suspensions, making it a practical and cost-effective branded choice compared with combination products and some suspension-based alternatives.

  • Rapid IOP drop

  • Low irritation

  • Clinic staple, woof!

  • Dorzolamide 2% topical solution that lowers intraocular pressure by inhibiting carbonic anhydrase.

  • Brand formulation with consistent drop size and preservative profile; often used off-label in dogs for glaucoma.

  • Rapid IOP drop

  • Low irritation

  • Clinic staple, woof!

  • Dorzolamide 2% topical solution that lowers intraocular pressure by inhibiting carbonic anhydrase.

  • Brand formulation with consistent drop size and preservative profile; often used off-label in dogs for glaucoma.

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$35-80 CAD

2
BEST BRINZOLAMIDE SUSPENSION (CANINE)

Azopt (Brinzolamide) 1% Ophthalmic Suspension

Azopt (Brinzolamide) 1% Ophthalmic Suspension

Azopt is the market-leading brinzolamide 1% suspension, valued in canine ophthalmology for a formulation that can be more comfortable and less stinging than acidic aqueous solutions. Compared with dorzolamide brands, Azopt often provides similar carbonic anhydrase inhibition with a distinct suspension profile — a technical advantage for tolerability in some dogs but sometimes at a higher branded price than generic monotherapies.

4.3
★★★★☆
  • Creamy suspension

  • Clear vision aid

  • Creamy suspension

  • Clear vision aid

Review Summary

87%

"Owners and veterinarians commonly praise brinzolamide for solid IOP control with less stinging than dorzolamide, though the suspension can blur vision briefly and requires shaking."

  • Smooth pour — tail-wag!

  • Brinzolamide 1% ophthalmic suspension reduces aqueous humor production via carbonic anhydrase inhibition.

  • Smooth pour — tail-wag!

  • Brinzolamide 1% ophthalmic suspension reduces aqueous humor production via carbonic anhydrase inhibition.

Increased Safety & Security

Time-Saving Convenience

Azopt is the market-leading brinzolamide 1% suspension, valued in canine ophthalmology for a formulation that can be more comfortable and less stinging than acidic aqueous solutions. Compared with dorzolamide brands, Azopt often provides similar carbonic anhydrase inhibition with a distinct suspension profile — a technical advantage for tolerability in some dogs but sometimes at a higher branded price than generic monotherapies.

  • Creamy suspension

  • Clear vision aid

  • Smooth pour — tail-wag!

  • Brinzolamide 1% ophthalmic suspension reduces aqueous humor production via carbonic anhydrase inhibition.

  • Suspension formulation may be better tolerated by some animals but requires shaking before use to ensure uniform dosing.

  • Creamy suspension

  • Clear vision aid

  • Smooth pour — tail-wag!

  • Brinzolamide 1% ophthalmic suspension reduces aqueous humor production via carbonic anhydrase inhibition.

  • Suspension formulation may be better tolerated by some animals but requires shaking before use to ensure uniform dosing.

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$40-90 CAD

3
BEST FIXED-COMBINATION THERAPY (CANINE GLAUCOMA)

Cosopt (Dorzolamide-Timolol) Ophthalmic Solution

Cosopt (Dorzolamide-Timolol) Ophthalmic Solution

Cosopt pairs dorzolamide with timolol to deliver combined CAI and beta-blocker effects in a single bottle, offering stronger intraocular pressure reduction potential for dogs than CAI monotherapy. Although typically more expensive and requiring attention to systemic beta-blocker considerations in veterinary patients, Cosopt’s combination dosing reduces administration complexity and can improve adherence and overall cost-effectiveness where dual-mechanism control is indicated.

4.1
★★★★☆
  • Dual-action control

  • Broad pressure cut

  • Dual-action control

  • Broad pressure cut

Review Summary

82%

"Users value Cosopt's superior IOP lowering and the convenience of combination therapy, but some report systemic beta‑blocker side effects (e.g., slowed heart rate) and note higher cost."

  • Power duo — superhero!

  • Combination dorzolamide–timolol provides dual mechanism: carbonic anhydrase inhibition plus beta-blockade for stronger intraocular pressure reduction.

  • Power duo — superhero!

  • Combination dorzolamide–timolol provides dual mechanism: carbonic anhydrase inhibition plus beta-blockade for stronger intraocular pressure reduction.

Increased Safety & Security

Time-Saving Convenience

Cosopt pairs dorzolamide with timolol to deliver combined CAI and beta-blocker effects in a single bottle, offering stronger intraocular pressure reduction potential for dogs than CAI monotherapy. Although typically more expensive and requiring attention to systemic beta-blocker considerations in veterinary patients, Cosopt’s combination dosing reduces administration complexity and can improve adherence and overall cost-effectiveness where dual-mechanism control is indicated.

  • Dual-action control

  • Broad pressure cut

  • Power duo — superhero!

  • Combination dorzolamide–timolol provides dual mechanism: carbonic anhydrase inhibition plus beta-blockade for stronger intraocular pressure reduction.

  • Single-bottle fixed-dose regimen can simplify dosing when both agents are indicated for canine glaucoma management.

  • Dual-action control

  • Broad pressure cut

  • Power duo — superhero!

  • Combination dorzolamide–timolol provides dual mechanism: carbonic anhydrase inhibition plus beta-blockade for stronger intraocular pressure reduction.

  • Single-bottle fixed-dose regimen can simplify dosing when both agents are indicated for canine glaucoma management.

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$60-120 CAD

4
BEST GENERIC DORZOLAMIDE (AFFORDABLE CANINE)

Dorzolamide 2% Generic Ophthalmic Solution

Dorzolamide 2% Generic Ophthalmic Solution

Generic dorzolamide 2% solutions provide the same active CAI ingredient as Trusopt but at lower acquisition cost, making them a budget-friendly option for long-term topical management of glaucoma in dogs. Manufacturing differences in preservatives and bottle design can slightly affect comfort, dosing convenience, or shelf life, but generics generally match branded pharmacologic efficacy while delivering meaningful financial savings for clinics and owners.

4
★★★★☆
  • Budget-friendly pick

  • Equivalent efficacy

  • Budget-friendly pick

  • Equivalent efficacy

Review Summary

80%

"Generic dorzolamide is generally reported to match brand efficacy at a lower cost, with occasional complaints about packaging, shelf life, or slightly increased stinging depending on manufacturer."

  • No-frills hero — yay!

  • Generic dorzolamide 2% offers the same active carbonic anhydrase inhibitory effect at a lower cost.

  • No-frills hero — yay!

  • Generic dorzolamide 2% offers the same active carbonic anhydrase inhibitory effect at a lower cost.

Increased Safety & Security

Time-Saving Convenience

Generic dorzolamide 2% solutions provide the same active CAI ingredient as Trusopt but at lower acquisition cost, making them a budget-friendly option for long-term topical management of glaucoma in dogs. Manufacturing differences in preservatives and bottle design can slightly affect comfort, dosing convenience, or shelf life, but generics generally match branded pharmacologic efficacy while delivering meaningful financial savings for clinics and owners.

  • Budget-friendly pick

  • Equivalent efficacy

  • No-frills hero — yay!

  • Generic dorzolamide 2% offers the same active carbonic anhydrase inhibitory effect at a lower cost.

  • Widely available and suitable for long-term off-label management of elevated intraocular pressure in dogs.

  • Budget-friendly pick

  • Equivalent efficacy

  • No-frills hero — yay!

  • Generic dorzolamide 2% offers the same active carbonic anhydrase inhibitory effect at a lower cost.

  • Widely available and suitable for long-term off-label management of elevated intraocular pressure in dogs.

Order Now

$20-50 CAD

5
BEST GENERIC BRINZOLAMIDE (AFFORDABLE SUSPENSION)

Brinzolamide 1% Generic Ophthalmic Suspension

Brinzolamide 1% Generic Ophthalmic Suspension

Generic brinzolamide 1% suspensions reproduce Azopt’s active profile at reduced cost, offering an economical suspension option for canine patients who tolerate particulate formulations. Variability in particle size and viscosity across suppliers can influence transient blur or dosing consistency, yet generics remain attractive for practices seeking lower-cost brinzolamide therapy while accepting slight formulation trade-offs compared with the Azopt benchmark.

4.1
★★★★☆
  • Affordable suspension

  • Dog-friendly texture

  • Affordable suspension

  • Dog-friendly texture

Review Summary

83%

"Generic brinzolamide is seen as an affordable alternative to the brand with similar pressure control, though users sometimes report more sediment, the need for vigorous shaking, or variable bottle quality."

  • Value drop — paw-approved!

  • Generic brinzolamide 1% suspension provides cost-effective carbonic anhydrase inhibition for canine glaucoma.

  • Value drop — paw-approved!

  • Generic brinzolamide 1% suspension provides cost-effective carbonic anhydrase inhibition for canine glaucoma.

Increased Safety & Security

Time-Saving Convenience

Generic brinzolamide 1% suspensions reproduce Azopt’s active profile at reduced cost, offering an economical suspension option for canine patients who tolerate particulate formulations. Variability in particle size and viscosity across suppliers can influence transient blur or dosing consistency, yet generics remain attractive for practices seeking lower-cost brinzolamide therapy while accepting slight formulation trade-offs compared with the Azopt benchmark.

  • Affordable suspension

  • Dog-friendly texture

  • Value drop — paw-approved!

  • Generic brinzolamide 1% suspension provides cost-effective carbonic anhydrase inhibition for canine glaucoma.

  • Requires shaking before administration to ensure even suspension and consistent dosing.

  • Affordable suspension

  • Dog-friendly texture

  • Value drop — paw-approved!

  • Generic brinzolamide 1% suspension provides cost-effective carbonic anhydrase inhibition for canine glaucoma.

  • Requires shaking before administration to ensure even suspension and consistent dosing.

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$25-60 CAD

What the Research and Clinical Experience Say

Clinical studies and veterinary reports support the use of topical dorzolamide and brinzolamide for lowering IOP in dogs, with established safety profiles when dosed under veterinary supervision. Research also shows additive benefits when CAIs are combined with other topical agents (for example, timolol), and highlights practical considerations such as dosing frequency, tolerability, and the role of preservatives. The science is accessible for pet owners: topical CAIs reduce aqueous humor production by blocking the carbonic anhydrase enzyme in ocular tissues, resulting in measurable and often clinically meaningful reductions in IOP.

Efficacy: Controlled studies and veterinary case series report clinically meaningful reductions in IOP with topical dorzolamide and brinzolamide in dogs; combination therapy (dorzolamide plus timolol) typically achieves greater reductions than a CAI alone.

Onset and duration: Topical CAIs usually show IOP-lowering onset within hours, with typical dosing intervals ranging from two to three times daily depending on product and disease severity.

Safety: Systemic absorption is limited relative to oral CAIs, so systemic side effects are uncommon; ocular irritation and transient stinging are the most commonly reported local effects.

Preservatives and ocular surface health: Products containing preservatives such as benzalkonium chloride may exacerbate chronic ocular surface disease; preservative-free or lower-preservative options are preferred for long-term administration.

Practical outcomes: Studies and clinical practice emphasize adherence, correct drop administration, and regular IOP monitoring to preserve vision—owner education significantly improves outcomes.

Regulatory and access notes: In Canada, these medications are prescription-only; veterinarians may recommend branded or generic formulations and, in some cases, compounded alternatives when standard options are unavailable.

In the Canadian 2025 context, topical carbonic anhydrase inhibitors remain a cornerstone for managing canine glaucoma. The five featured options on this page — Trusopt (Dorzolamide) 2% Ophthalmic Solution, Azopt (Brinzolamide) 1% Ophthalmic Suspension, Cosopt (Dorzolamide-Timolol) Ophthalmic Solution, Dorzolamide 2% Generic Ophthalmic Solution, and Brinzolamide 1% Generic Ophthalmic Suspension — each have roles depending on clinical needs, cost considerations, and tolerance. For many dogs, Trusopt (Dorzolamide) 2% Ophthalmic Solution is a solid first-line choice because of its established efficacy and veterinary familiarity; Cosopt is often the preferred next step when additional IOP lowering is required through combination therapy. Azopt and the generic dorzolamide and brinzolamide products provide effective and more budget-conscious alternatives. I hope you found this guide useful — refine or expand your search by product name, formulation, or dosing needs to find the best option for your dog, and consult your veterinarian for diagnosis and a tailored treatment plan.

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