Ripasudil Eye Drops: Uses, Dosage, and Side Effects

Ripasudil is a prescription eye drop used to lower eye pressure in people with glaucoma or ocular hypertension, and it works through a mechanism unlike any other glaucoma drug on the market. Approved in Japan in 2014 as the world’s first Rho kinase (ROCK) inhibitor eye drop, ripasudil directly targets the eye’s natural drainage tissue to let fluid exit more efficiently. Its story has grown well beyond simple pressure-lowering, though, with emerging research into corneal healing, nerve protection, and surgical recovery making it one of the more versatile ophthalmic molecules under study today.

How Ripasudil Lowers Eye Pressure

Most glaucoma drops work by either reducing the amount of fluid the eye produces or opening an alternative drainage route. Ripasudil does something different. It relaxes the structural scaffolding inside the cells of the trabecular meshwork and Schlemm’s canal, the eye’s main drainage pathway. By breaking down rigid protein filaments inside those cells, the drug makes the tissue more porous and allows aqueous humor to flow out through the route it was always meant to use.¹ This is called working on the “conventional outflow” pathway, and it matters because dysfunction in that pathway is the primary cause of elevated pressure in the most common form of glaucoma.

Once instilled, ripasudil is absorbed rapidly through the cornea and distributes throughout the eye, concentrating especially in pigmented tissues like the iris and the layer behind the retina.² Its effects on pressure kick in quickly, but they also wear off relatively fast, which is why the standard dosing is twice a day rather than once.

Approved Uses and Dosing

Ripasudil 0.4% ophthalmic solution is approved in Japan for the treatment of glaucoma and ocular hypertension when other drugs have not worked well enough or cannot be used.³ In practice, that positioning means it is often prescribed as an add-on to existing therapy rather than as a first-line treatment, though it is also used on its own when other medications cause intolerable side effects.

The standard dose is one drop of 0.4% solution in the affected eye, twice daily. The twice-daily schedule reflects the drug’s relatively short duration of action. A one-year clinical evaluation found that ripasudil maintained its pressure-lowering effect over 52 weeks, with average reductions of about 2.6 mmHg at the trough (right before the next dose) and 3.7 mmHg at peak effect when used as monotherapy.⁴ A separate trial in newly diagnosed open-angle glaucoma patients reported a similar magnitude of pressure reduction, with roughly half the patients reaching their target pressure on ripasudil alone.⁵

In eyes with high myopia and pathological myopia, a population sometimes tricky to treat, ripasudil still delivered meaningful results. Pressure dropped by about 9% at four weeks and 12% at twelve weeks from baseline when ripasudil was added to existing therapy.⁶

Using Ripasudil Alongside Other Glaucoma Drops

Because glaucoma often requires more than one medication to reach a safe pressure target, much of the clinical data on ripasudil examines it as an add-on. Two randomized trials tested ripasudil combined with either timolol (a beta-blocker drop) or latanoprost (a prostaglandin analog). When added to timolol, ripasudil provided an additional pressure reduction of about 0.9 mmHg before the next dose and 1.6 mmHg at peak, both statistically significant over placebo. When added to latanoprost, the peak-effect benefit was similar (about 1.4 mmHg), although the trough benefit was smaller and did not reach statistical significance.⁷

For patients already on the maximum number of glaucoma drops who still have uncontrolled pressure, ripasudil has shown it can squeeze out additional benefit. A study of such patients found a further 17% reduction in pressure (roughly 2.9 mmHg) after three months of adding ripasudil to everything they were already taking.⁸ That margin can be the difference between keeping a patient stable on drops versus sending them to surgery.

Effectiveness in Secondary Glaucoma

Not all glaucoma is the straightforward open-angle variety. Several types of “secondary” glaucoma arise from other eye conditions, and ripasudil has shown particular promise in some of them.

In pseudoexfoliative glaucoma, a form driven by flaky protein deposits that clog the drainage system, ripasudil as an add-on lowered pressure progressively over six months, with reductions reaching about 24% by the end of the study period. Thirty-five of 40 patients hit their target pressure.⁹

A multicentre study (called ROCK-S) looked at ripasudil across three secondary glaucoma types: uveitic glaucoma, exfoliation glaucoma, and steroid-induced glaucoma. All three groups saw significant pressure drops. Steroid-induced glaucoma showed some of the largest reductions, with a mean decrease of about 9 mmHg at one month and nearly 29% at six months. Uveitic glaucoma responded even more dramatically in percentage terms, with reductions approaching 37% at six months.¹⁰ These results matter because secondary glaucomas are often harder to control and can be more aggressive than primary open-angle disease.

The large post-marketing surveillance study that tracked over 3,400 patients in Japan confirmed meaningful pressure reductions across all glaucoma subtypes, including uveitic glaucoma (about 4.7 mmHg reduction), steroid-induced glaucoma (about 5.5 mmHg), and even angle-closure glaucoma (about 3.9 mmHg).¹¹

Side Effects You Should Expect

The most noticeable side effect of ripasudil is conjunctival hyperemia, a redness of the white of the eye that occurs because the drug dilates blood vessels on the eye’s surface. This is extremely common. In clinical trials, somewhere between half and two-thirds of patients experience it to some degree.¹² The redness is most intense about 10 minutes after putting the drop in and typically fades within 60 to 90 minutes. A clinical trial that specifically measured the timeline of this redness found the median offset was 90 minutes, though in many patients it cleared within an hour.¹³ This side effect is cosmetically annoying but not harmful. Most doctors advise patients to time their drops when they do not need to look presentable for about an hour or two.

More concerning from a long-term adherence standpoint is blepharitis, an inflammation of the eyelids that can cause itching, crusting, and irritation. A study tracking this over two years found that about a quarter of patients developed blepharitis, and the discontinuation rate due to this side effect climbed steadily, reaching roughly 35% by 24 months. Most patients recovered within four weeks of stopping the drug, though a handful needed over eight weeks. Having a history of allergic reactions to other glaucoma drops was a significant predictor of developing blepharitis with ripasudil.¹⁴

The large 24-month surveillance study of over 3,300 Japanese patients confirmed a similar overall side effect profile: about 25% experienced some adverse reaction, with blepharitis, conjunctival hyperemia, and conjunctivitis each affecting roughly 6 to 9% of users. Female patients, those with a history of pollen allergies, and those with prior medication allergies were more prone to developing blepharitis.¹⁵

Side effects outside the eye are rare. Reported systemic reactions include occasional constipation, headache, dizziness, and nausea, each affecting well under 1% of patients. One retrospective report did note a drop in blood pressure about a month after starting ripasudil, though severe systemic reactions remain uncommon.¹¹

How Ripasudil Compares to Netarsudil

The only other ROCK inhibitor approved for glaucoma is netarsudil (marketed as Rhopressa in the United States), so patients and doctors naturally want to know how the two stack up. A head-to-head Phase 3 trial in Japanese patients found that netarsudil dosed once daily lowered average daily pressure by about 4.7 mmHg, compared with 3.0 mmHg for ripasudil dosed twice daily, a difference of roughly 1.7 mmHg in netarsudil’s favor.¹² A separate comparative study reported a similar gap of about 2.3 mmHg at three months.¹⁶

Side effects were somewhat less frequent with netarsudil in these trials, though both drugs cause high rates of redness and irritation. The overall incidence of adverse events hovered around 60 to 67% for ripasudil versus about 55 to 60% for netarsudil.¹² Netarsudil also has its own distinctive side effect profile, including corneal deposits called verticillata, which ripasudil does not cause. Which drug is “better” depends partly on what is available where you live: netarsudil is widely prescribed in the United States and Europe, while ripasudil has deeper clinical experience and broader off-label use in Japan and parts of Asia.

Corneal Healing and Post-Surgical Protection

Beyond glaucoma, ripasudil has generated considerable excitement for its effects on the corneal endothelium, the thin cell layer on the inside surface of the cornea that keeps it clear. When these cells are damaged or diseased, the cornea swells and vision deteriorates. Traditionally the main fix has been corneal transplant surgery. Ripasudil could change that calculus for some patients.

Lab and tissue studies have shown that ripasudil stimulates corneal endothelial cells to migrate and proliferate, particularly in tissue affected by Fuchs endothelial corneal dystrophy (FECD), a progressive condition that is one of the leading reasons for corneal transplants. A single dose of ripasudil ramped up genes involved in cell division, migration, and the pump function that keeps the cornea dehydrated and transparent, while simultaneously dialing down genes linked to harmful tissue scarring.¹⁷ An ex vivo model that mimicked Descemet’s stripping (a surgical technique that removes the diseased endothelial layer to let healthy cells migrate in) showed enhanced cell migration when ripasudil was present.¹⁸

A large retrospective study moved this from the lab into real patients. Those treated with ripasudil for corneal edema saw central corneal thickness decrease by about 30 micrometers on average, and visual acuity improved meaningfully. In the FECD subgroup specifically, corneal thickness dropped by about 26 micrometers with significant improvement in vision. Endothelial cell counts stayed stable, suggesting the improvement came from better cell function rather than from new cells replacing dead ones.¹⁹

Even in routine cataract surgery, where some corneal endothelial cell loss is expected, ripasudil appears protective. A prospective study comparing patients who received ripasudil drops after cataract surgery against controls found endothelial cell loss of just 4.5% in the ripasudil group compared with 12.8% in controls.²⁰ That kind of difference could be meaningful for patients who already have borderline endothelial cell counts heading into surgery.

Neuroprotection Research

Lowering eye pressure is the only proven way to slow glaucoma, but researchers have long wanted drugs that also protect the retinal ganglion cells, the nerve cells that actually die in the disease. Animal studies suggest ripasudil may have direct neuroprotective properties independent of its pressure-lowering effect.

In a mouse model of normal-tension glaucoma, where damage occurs despite normal pressure, topical ripasudil significantly reduced the death of retinal ganglion cells across the entire retina.²¹ A separate study using optic nerve crush injury in adult mice found that ripasudil not only prevented ganglion cell death but also stimulated some degree of axon regrowth.²² Lab experiments have also shown that ripasudil protects ganglion cells from oxidative stress, in part by suppressing a damaging enzyme called calpain.²³

All of this is preclinical, meaning it has been demonstrated in lab dishes and animal models but not yet proven in human glaucoma patients. The leap from mouse retina to human clinical outcomes is large, and neuroprotection trials in glaucoma are notoriously difficult to design. Still, the consistency of the animal data across multiple labs and models keeps interest alive, and the fact that ripasudil is already approved for human use as a pressure-lowering drop means it could potentially be studied for neuroprotection without starting the drug development process from scratch.

Other Corneal and Inflammatory Conditions Under Study

The ROCK pathway that ripasudil targets is involved in far more than just eye pressure. It regulates cell movement, inflammation, scar formation, and blood vessel growth throughout the eye. This has led researchers to explore ripasudil for a range of conditions beyond glaucoma, including pseudophakic bullous keratopathy (corneal swelling after certain eye surgeries), iridocorneal endothelial syndrome, and other conditions characterized by corneal endothelial failure.²⁴ The anti-inflammatory and anti-fibrotic properties of ROCK inhibitors also make them candidates for managing wound healing after corneal procedures, potentially reducing scarring that can cloud vision.

A fixed-dose combination eye drop pairing ripasudil with brimonidine has been evaluated for uveitis-related secondary glaucoma, aiming to simplify the regimen for patients juggling many medications. Early retrospective data suggests the combination effectively lowers pressure in this difficult population, consistent with what has been seen with ripasudil alone.²⁵

Availability Outside Japan

Ripasudil was first approved in Japan in 2014 and remains most widely used there, where it has accumulated the largest body of real-world clinical experience.³ It has since gained approval in several other Asian markets, including India, where a growing number of comparative studies have been conducted. It has not been approved by the U.S. Food and Drug Administration or the European Medicines Agency. In those markets, netarsudil fills the ROCK-inhibitor niche, often in a fixed combination with latanoprost (marketed as Rocklatan or Rhokiinsa).

For patients outside Japan or India who are curious about ripasudil, the practical takeaway is that the class of drugs it belongs to is available in most countries, just in a different formulation. The unique corneal-healing and neuroprotective applications of ripasudil are still investigational everywhere and are not yet part of any country’s approved labeling. Ongoing work on diabetic retinopathy has also been flagged in early-phase trials, broadening the drug’s potential relevance if those studies pan out.