This page shows what was measured, who it was measured in, and what that does not settle.
What Dorzolamide does in the body
Dorzolamide jams that enzyme, so the raw material runs short, the pump slows and pressure falls.
The tissue behind your iris pumps fluid into the eye, and the pump is driven by a salt the cells have to manufacture on the spot. One enzyme does that manufacturing. The same enzyme sits in the cells that keep the cornea clear, which is why an eye with an already-damaged cornea can be pushed over the edge by it.
Why people take it. High pressure inside the eye, treated by slowing the chemistry that drives fluid production
What happened in people
Mean intraocular pressure reduction of 2.49 mmHg (95% credible interval 1.85 to 3.13) at three months, pooled across 114 randomised trials in 20,275 participants
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The recorded finding that sits closest to something a person would notice. Written into the record, not signed off, and it carries no population or interval.
That dorzolamide protects the optic nerve through improved ocular perfusion — measured as blood velocity, never against a vision endpoint
Where it acts
Ciliary process epithelium, where bicarbonate transport drives the secretion of aqueous humour
Kind of result
The kind of result is not recorded
Supervision
RNAWiki has not recorded a supervision or regulatory status for this substance.
What the registries record it as
The substance registry classes this as chemical.
FDA substance registry · QZO5366EW7 · read 2026-08-29
Its recorded molecular formula is C10H16N2O4S3·HCl, weighing 360.9.
US prescribing information · fb2e0729-b0bc-4c3f-9961-8bb38f84a032 · read 2026-08-30
Where each sentence above came from
A person wrote this explanation into the record, with the studies named in the path below.
The recorded use, written for a reader without medical training. Not signed off.
A limit recorded against this substance. Not signed off as a reviewed claim.
The four opening statements run to 118 words.
Words this page uses
Four words worth knowing first
Chosen from what this page shows, with each one explained before the word it depends on.
Placebo
A placebo is a dummy treatment given so the real one can be compared with it.
A picture of it, and where the picture fails
A placebo is like a blank control in an experiment.
Where that stops being true. A blank does nothing. People given a placebo often do get better.
What people get wrong. A placebo effect is read as imaginary. The improvement is measured and real.
An inactive intervention matched in appearance to the test intervention, used to control for non-specific effects.
Comparator
A comparator is whatever the treatment was measured against.
A picture of it, and where the picture fails
It is like the other runner in a race.
Where that stops being true. A race has one winner. A study can show both arms improved.
What people get wrong. Results are read without asking what the other group got. Beating nothing is not beating a treatment.
The control condition against which the experimental intervention is assessed.
Randomisation
Randomisation means chance decides who gets which treatment.
A picture of it, and where the picture fails
It is like a coin toss deciding the groups.
Where that stops being true. A coin toss is fair once. Fairness here comes from doing it for everyone.
What people get wrong. It is thought to make groups identical. It makes them similar on average, including on things nobody measured.
Allocation of participants to arms by a chance process, so that unmeasured factors are balanced in expectation.
What happened in people◇Read from sources, not yet reviewed
What happened in people
Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.
Safety profile and intraocular pressure reduction at up to one year, dorzolamide against timolol and betaxolol
✓ The study showed what it set out to show
Who was studied
International Dorzolamide Study (Strahlman 1995)
How many people
523
Study design
Double-masked, randomised, parallel comparison at 34 international sites
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Peak reduction approximately 23% dorzolamide, 25% timolol, 21% betaxolol; trough 17%, 20%, 15%. Reported descriptively rather than with a p-value for the primary comparison.
Repeated elsewhere
Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Corneal decompensation in patients with pre-existing endothelial compromise was not identified here. It emerged from a case series four years after approval and is now a labelled warning.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Topical ophthalmic solution 2%, instilled three times daily as monotherapy
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Orzalesi N, Rossetti L, Invernizzi T, Bottoli A, Autelitano A. Effect of timolol, latanoprost, and dorzolamide on circadian IOP in glaucoma or ocular hyperte… · a recorded source, not a stored snapshot
Diurnally corrected intraocular pressure reduction at peak and trough over 3 months, brinzolamide against dorzolamide and timolol
Dorzolamide three times daily -4.3 to -5.9 mmHg, statistically equivalent to brinzolamide (confidence limit ≤1.5 mmHg); ocular discomfort 16.4% against 1.8%, P = .000
Repeated elsewhere
Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Sponsored by Alcon, the manufacturer of the comparator that won on tolerability. The efficacy finding is equivalence, so the trial’s conclusion rests entirely on the side effect it was best placed to detect.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Topical ophthalmic solution 2%, instilled three times daily as monotherapy
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Orzalesi N, Rossetti L, Invernizzi T, Bottoli A, Autelitano A. Effect of timolol, latanoprost, and dorzolamide on circadian IOP in glaucoma or ocular hyperte… · a recorded source, not a stored snapshot
Around-the-clock intraocular pressure reduction, dorzolamide against timolol and latanoprost
Significant reduction against baseline at all eight measurement times; superior to timolol at midnight and 3 AM (P = 0.05 both)
Repeated elsewhere
Partially Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Twenty patients across three one-month treatment periods. Small, unreplicated at this level of measurement detail, and the source of a claim now made routinely about the whole class.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Topical ophthalmic solution 2%, instilled three times daily as monotherapy
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Orzalesi N, Rossetti L, Invernizzi T, Bottoli A, Autelitano A. Effect of timolol, latanoprost, and dorzolamide on circadian IOP in glaucoma or ocular hyperte… · a recorded source, not a stored snapshot
Ocular perfusion pressure and retrobulbar blood flow velocities after one month, dorzolamide/timolol against brimonidine/timolol
✗ The study did not show it
Who was studied
Siesky retrobulbar haemodynamics crossover (2012)
How many people
15
Study design
Prospective, randomised, double-blind crossover
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
No significant difference between combinations in intraocular pressure, blood pressure, ocular perfusion pressure or retrobulbar flow velocities
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. Fifteen patients with already well-controlled pressure. A null result in a sample this size is weak evidence of no effect, and it is quoted here only because it is the direct test of a claim usually made without any test at all.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Topical ophthalmic solution 2%, instilled three times daily as monotherapy
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Orzalesi N, Rossetti L, Invernizzi T, Bottoli A, Autelitano A. Effect of timolol, latanoprost, and dorzolamide on circadian IOP in glaucoma or ocular hyperte… · a recorded source, not a stored snapshot
What we know
RNAWiki holds 4 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Start
Dorzolamide
What a person takes: Topical ophthalmic solution 2%, instilled three times daily as monotherapy.
The measurement behind this step
An aqueous solution buffered to roughly pH 5.6, which is where the compound is soluble and stable and also why it stings. It crosses the cornea to the ciliary body, and the systemically absorbed fraction binds carbonic anhydrase in red blood cells, where it accumulates with a washout measured in months rather than hours.
Getting in
An acidic drop that most people can feel
The drop is buffered to be acidic, because that is the only way to keep enough of the drug dissolved. That is why one person in six finds it stings.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Dorzolamide hydrochloride 2% is formulated as an aqueous solution at roughly pH 5.6, the range in which the compound is both soluble and chemically stable. The head-to-head trial recorded burning and stinging on instillation in 16.4% of dorzolamide patients against 1.8% on the near-neutral brinzolamide suspension.
The drug passes through the clear front of the eye and reaches the tissue behind the iris that makes the fluid. A fraction also enters the bloodstream, where it sticks to red blood cells for months.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Dorzolamide partitions across the cornea into the aqueous humour and reaches the ciliary process epithelium. Systemically absorbed drug binds carbonic anhydrase in erythrocytes, and both dorzolamide and its N-desethyl metabolite accumulate there, producing a red cell washout measured in months. That accumulation is why a topically applied sulfonamide can still produce a systemic sulfonamide reaction.
A sulfonamide group grabs the zinc atom in the enzyme
The enzyme it targets has a single zinc atom at its heart, and that is where all the chemistry happens. One end of the drug molecule locks onto the zinc and shuts the site down.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
The unsubstituted primary sulfonamide deprotonates and coordinates the catalytic zinc ion in the active site of carbonic anhydrase II, displacing the zinc-bound hydroxide that performs catalysis. This binding mode is shared by every drug in the class from acetazolamide onwards, which is why the SO2NH2 group cannot be modified. The rest of the molecule, the thienothiopyran scaffold, is what Merck engineered for potency and aqueous solubility.
Without the enzyme, the cells cannot make the salt that drives fluid into the eye. Sodium and water follow the salt, so when the salt stops moving, so does the fluid.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Carbonic anhydrase II catalyses the hydration of carbon dioxide to bicarbonate and a proton in the ciliary epithelium. Inhibition slows bicarbonate formation, which reduces the sodium and fluid transport coupled to it, and therefore the rate of aqueous humour secretion. The label describes the mechanism in exactly these terms and uses the word "presumably" for the coupling step.
Pressure falls, and unusually it falls at night too
Pressure drops by about two and a half millimetres of mercury. Unlike the beta-blockers, the effect holds through the small hours, because it does not depend on nerve signals that quieten during sleep.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Pooled reduction is 2.49 mmHg (95% credible interval 1.85 to 3.13) at three months, eleventh of fourteen first-line agents. In 24-hour tonometry dorzolamide significantly reduced pressure against baseline at all eight measurement times and outperformed timolol at midnight and 3 AM. Bicarbonate-dependent secretion does not have the same circadian collapse as sympathetically driven secretion.
The cornea stays transparent because a layer of cells on its inner surface pumps water out of it continuously. That pump uses the same enzyme. In an eye whose cornea is already damaged, blocking it can tip the balance.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
The corneal endothelium maintains stromal deturgescence through a bicarbonate-dependent pump involving membrane-anchored carbonic anhydrase. In a series of nine patients with pre-existing endothelial compromise — previous grafts, aphakia, anterior chamber lenses, Fuchs dystrophy — overt corneal decompensation developed 3 to 20 weeks after starting dorzolamide and did not reverse on stopping. Seven required penetrating keratoplasty. The label carries this as Warnings and Precautions 5.3.
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 6 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
What is missing or unclear◇Read from sources, not yet reviewed
Were people like you studied?
RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.
Who was studied
People similar to this profile were included.
Adults with open-angle glaucoma or ocular hypertension, usually as a second or third agent. It is one of the few options in people for whom beta-blockade is contraindicated by asthma or heart block.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What the label states about particular groups
On pediatric, the label states: “Safety and effectiveness of dorzolamide hydrochloride ophthalmic solution have been demonstrated in pediatric patients in a 3-month, multicenter, double-masked, active-treatment-controlled trial.”
US prescribing information · fb2e0729-b0bc-4c3f-9961-8bb38f84a032 · read 2026-08-30
On older people, the label states: “No overall differences in safety or effectiveness have been observed between elderly and younger patients.”
US prescribing information · fb2e0729-b0bc-4c3f-9961-8bb38f84a032 · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary There are no adequate and well-controlled studies in pregnant women with dorzolamide hydrochloride.”
US prescribing information · fb2e0729-b0bc-4c3f-9961-8bb38f84a032 · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary There are no data on the presence of dorzolamide hydrochloride in human milk, the effects on the breastfed infant, or the effects on milk production.”
US prescribing information · fb2e0729-b0bc-4c3f-9961-8bb38f84a032 · read 2026-08-30
Where the result stopped carrying
Corneal decompensation in eyes with compromised endothelium was not seen in the 523-patient registration programme and was described four years after approval
The formulation stings: 16.4% of patients reported burning on instillation, which is the reason a competitor built on the same mechanism took the market
Three-times-daily dosing was required for monotherapy, against twice daily for the beta-blockers it was competing with
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
Other reasons RNAWiki checked and found nothing for (11)
It was studied for a different goal
The studies measured something else entirely. Nothing in this record points to this reason.
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Prescription only
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Topical ophthalmic solution 2%, instilled three times daily as monotherapy
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form and route recorded on this substance.
No source is stored against this line.
Who oversees it
RNAWiki has not recorded a supervision or regulatory status for this substance.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
No register row and no identity class settled the question.
No source is stored against this line.
What is in the pack
6, which is where the compound is soluble and stable and also why it stings.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold. The rest of the recorded wording: It crosses the cornea to the ciliary body, and the systemically absorbed fraction binds carbonic anhydrase in red blood cells, where it accumulates with a washout measured in months rather than hours.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take◇Read from sources, not yet reviewed
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
Labelled warnings for sulfonamide hypersensitivity, bacterial keratitis from contaminated multi-dose containers, corneal endothelium, allergic reactions and acute angle-closure glaucoma. The sulfonamide warning states that fatalities have occurred rarely from Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anaemia and other blood dyscrasias, and that sensitisation may recur on readministration by any route. Ocular burning and stinging in roughly one patient in six. Bitter taste after instillation, from nasolacrimal drainage. Superficial punctate keratitis and ocular allergy. Unlike timolol it does not block beta receptors and is therefore usable in asthma and heart block.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.
Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What is missing or unclear◇Read from sources, not yet reviewed
Does the exact form matter?
Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.
The form that was studied
Topical ophthalmic solution 2%, instilled three times daily as monotherapy
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form used in the studies cited on this page.
No source is stored against this line.
What is sold
is soluble and stable and also why it stings.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on which forms are sold. The rest of the recorded wording: It crosses the cornea to the ciliary body, and the systemically absorbed fraction binds carbonic anhydrase in red blood cells, where it accumulates with a washout measured in months rather than hours.
No source is stored against this line.
What is recorded as being sold
52 products list this as an active ingredient in the United States drug directory. 29 of them contain it and nothing else.
FDA National Drug Code directory · 71921-226 · read 2026-08-29
They are sold as powder, solution and solution/ drops, taken ophthalmic.
FDA National Drug Code directory · 71921-226 · read 2026-08-29
The regulator's established pharmacologic class for it is carbonic anhydrase inhibitor [epc] and carbonic anhydrase inhibitors [moa].
FDA National Drug Code directory · 71921-226 · read 2026-08-29
38 published labels name it as an active ingredient. 15 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · fb2e0729-b0bc-4c3f-9961-8bb38f84a032 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · fb2e0729-b0bc-4c3f-9961-8bb38f84a032 · read 2026-08-29
Dorzolamide Hydrochloride is ophthalmic at 3 DOSAGE FORMS AND STRENGTHS Ophthalmic solution containing dorzolamide 2% (20 mg/mL) equivalent to 22.3 mg/mL of dorzolamide hydrochloride, USP., recorded as fda label in effect 2024-08-27 in the United States.
US prescribing information · fb2e0729-b0bc-4c3f-9961-8bb38f84a032 · read 2026-08-30
Recorded price in US: 0.83137 USD per one millilitre, across 11 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
RNAWiki could not confidently classify this substance, so no self-experiment plan is offered.
Questions worth asking
Which of the trials of Dorzolamide studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That dorzolamide protects the optic nerve through improved ocular perfusion — measured as blood velocity, never against a vision endpoint
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That topical delivery of a sulfonamide removes systemic sulfonamide risk; the label states the opposite for the severe reactions
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That the case series of nine corneal decompensations gives a rate — it has no denominator and cannot
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That overnight superiority to timolol translates into better preserved visual fields, which no trial has compared
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
Missing populations
Which groups were under-represented in the studies has not been recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing long-term data
No completed tested study window is recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
No reviewed conclusion
RNAWiki has not yet published a reviewed conclusion for this use.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing interaction studies
No interaction was found in the registers checked. Not finding one is not the same as showing there is none.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Formulation uncertainty
Several salts, forms or products of Dorzolamide are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Every line above can be traced to the study named beside it. Follow the link and read it.
Comparable to betaxolol and behind timolol at one year
In plain words
Five hundred and twenty-three patients at 34 sites took dorzolamide, timolol or betaxolol for a year. Dorzolamide sat between the two beta-blockers, closer to the weaker one, and did not cause the electrolyte problems that swallowed versions of the same drug do.
What was measured
Percent intraocular pressure reduction at peak and trough at one year, three-arm comparison
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The International Dorzolamide Study Group ran a double-masked, randomised, parallel comparison in 523 patients aged 17 to 85 with open-angle glaucoma or ocular hypertension at 34 international sites, after washout of prior medication. At one year, mean percent reduction in intraocular pressure at peak was approximately 23% for dorzolamide 2% three times daily, 25% for timolol 0.5% twice daily and 21% for betaxolol 0.5% twice daily. At afternoon trough the figures were 17%, 20% and 15%. The authors concluded that dorzolamide’s efficacy is comparable with betaxolol and that long-term use was not associated with clinically meaningful electrolyte disturbances or the systemic effects seen with oral carbonic anhydrase inhibitors.
Written into the record, not signed off as a reviewed claim
It keeps working at 3 AM, which timolol does not
In plain words
In a study that measured pressure every three hours around the clock, dorzolamide is weaker than timolol on average but beats it overnight — at midnight and at three in the morning, timolol’s two worst hours.
What was measured
Intraocular pressure at eight times across 24 hours, dorzolamide against timolol and latanoprost
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
In the 20-patient randomised crossover study with masked evaluators and inpatient 24-hour tonometry, all three study drugs significantly reduced pressure against baseline at every time point except timolol at 3 AM. Dorzolamide performed better than timolol at midnight and at 3 AM (P = 0.05 at both), while timolol was better than dorzolamide at 3 PM (P = 0.05). Latanoprost was better than dorzolamide at 9 AM, noon, 3 PM and 6 PM. The mechanistic reading is that aqueous secretion falls overnight, so a beta-blocker suppressing sympathetic drive has less to suppress, while carbonic anhydrase inhibition targets the bicarbonate transport that continues.
Source
Orzalesi N et al., Invest Ophthalmol Vis Sci 2000;41:2566-2573 (PMID 10937568)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
verified
Review state
Written into the record, not signed off as a reviewed claim
Nine corneas that did not recover when the drug was stopped
In plain words
Nine patients, all of whom had already had eye surgery, developed clouding of the cornea after starting dorzolamide. Stopping the drug did not fix it. Seven of them went on to need a corneal transplant.
What was measured
Irreversible corneal decompensation after starting dorzolamide, nine cases with endothelial compromise
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
A multicentre chart review documented nine eyes of nine patients who developed overt corneal decompensation after starting topical dorzolamide, at three to twenty weeks of therapy (mean 7.8 weeks), which did not resolve on stopping the drug. All nine had undergone intraocular surgery: eight had cataract surgery, three were aphakic, three had posterior chamber lenses, two had anterior chamber lenses plus trabeculectomies, four had previous penetrating keratoplasties each complicated by a treated allograft rejection episode, and two had asymptomatic Fuchs endothelial dystrophy. Seven have since undergone successful penetrating keratoplasty. The proposed mechanism is inhibition of carbonic anhydrase in the corneal endothelium, whose pump maintains stromal deturgescence. The FDA label carries a Corneal Endothelium warning as section 5.3. This is a case series with no denominator: it shows the harm is real and cannot state how often it occurs.
Written into the record, not signed off as a reviewed claim
One patient in six finds it painful to instil
In plain words
In the head-to-head trial against brinzolamide, 16.4% of dorzolamide patients reported burning and stinging on putting the drop in. On brinzolamide it was under 2%. That is a nine-fold difference in a side effect people stop the drug for.
What was measured
Incidence of ocular burning and stinging on instillation, dorzolamide against brinzolamide
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
In the 572-patient multicentre double-masked comparison, the incidence of ocular discomfort on instillation was 16.4% with dorzolamide 2% three times daily against 1.8% with brinzolamide twice daily and 3.0% with brinzolamide three times daily (P = .000 for the comparison). The mechanism is the formulation, not the molecule: dorzolamide is a solution buffered to roughly pH 5.6 because that is where the drug is soluble and stable, and brinzolamide is a near-neutral suspension. The trade is direct — brinzolamide’s comfort is bought by suspending a less soluble compound, and the suspension transiently blurs vision after instillation.
Written into the record, not signed off as a reviewed claim
The ocular blood flow claim was never converted into a vision outcome
In plain words
This drug is often said to protect the optic nerve by improving blood flow to the back of the eye, on top of lowering pressure. Nobody has shown that it preserves vision better than an equal drop in pressure achieved another way.
What was measured
That dorzolamide protects the optic nerve by improving ocular perfusion independently of pressure lowering — an argument built on Doppler velocity measurements, never tested against a vision endpoint
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
A prospective, randomised, double-blind crossover study measured intraocular pressure, blood pressure, ocular perfusion pressure and retrobulbar haemodynamics by colour Doppler imaging in 15 patients with open-angle glaucoma before and one month after treatment with brimonidine/timolol and dorzolamide/timolol. Intraocular pressure, blood pressure, ocular perfusion pressure and retrobulbar blood flow velocities did not differ significantly between the two combinations. Fifteen patients is a small study and its null result is weak evidence of no effect. The point stands regardless: the neuroprotection-through-perfusion argument for this drug has produced surrogate measurements of blood velocity and no randomised comparison with a visual field or optic disc endpoint.
Written into the record, not signed off as a reviewed claim
A drop is systemic: the sulfonamide warnings came with it
In plain words
Putting a sulfa drug in the eye instead of swallowing it removed the tingling, fatigue and kidney stones. It did not remove the rare, severe sulfonamide reactions, and the label says so.
What was measured
That topical delivery of a sulfonamide avoids systemic sulfonamide risk — true for the common dose-related toxicities and explicitly not true for the severe idiosyncratic ones
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The premise of the topical carbonic anhydrase inhibitor programme was that local delivery would separate the pressure-lowering effect from the systemic toxicity of oral acetazolamide, and on the common toxicities it worked: the one-year trial found no clinically meaningful electrolyte disturbance. The label states the limit of that separation directly. Dorzolamide is a sulfonamide and, although administered topically, is absorbed systemically, so the same types of adverse reactions attributable to sulfonamides may occur — and fatalities have occurred, rarely, from Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anaemia and other blood dyscrasias. The label further notes that sensitisation may recur when a sulfonamide is readministered by any route. Dorzolamide also accumulates in erythrocytes by binding carbonic anhydrase there, with a washout measured in months rather than hours.
Source
Dorzolamide hydrochloride ophthalmic solution US prescribing information, Warnings and Precautions 5.1 Sulfonamide Hypersensitivity and 5.3 Corneal Endothelium
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Not matched to a registered study
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Where else this substance is registered
FDA substance identifier (UNII)
QZO5366EW7
RxNorm concept
310015
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How this medicine reached us
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What the approval register records
37 approved applications cover products containing this substance. The earliest was NDA020408, approved 19941209 to MSD SUB MERCK.
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7 questions this page could not answer
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A thienothiopyran sulfonamide that shuts down carbonic anhydrase II in the ciliary epithelium and starves the fluid pump of bicarbonate, lowering pressure 2.49 mmHg at three months across 114 pooled trials — eleventh of fourteen first-line drops — while keeping its effect at 3 AM where timolol loses it, and carrying a label warning for irreversible corneal decompensation after a case series in which seven of nine affected patients needed a corneal transplant.
Recorded evidence blocks (8)
Q1
On the Dorzolamide label: indicated for what?
"Dorzolamide hydrochloride ophthalmic solution is indicated in the treatment of elevated intraocular pressure in patients with ocular hypertension or open-angle glaucoma. Dorzolamide hydrochloride ophthalmic solution is a carbonic anhydrase inhibitor indicated for the treatment of elevated intraocular pressure in…": indications and usage on Dorzolamide's label. DailyMed label · 8417d162-65a1-4266-bca7-707af1193bf3 · 2026-06-29
Q2
16 registered trials of Dorzolamide — at which phases?
NCT00333125, NCT00675207, NCT00314171, NCT00619034, NCT01887223 and NCT02522039, and 3 more
Completion dates
oldest 2007-02; newest 2021-08-10
Show the evidence
Trial
NCT00333125
2007-02
NCT00675207
2007-07
NCT00314171
2007-08
NCT00619034
2010-12
NCT01887223
2011-06
NCT02522039
2014-11
3 further recorded trials
NCT02967614
2018-04-01
NCT05973305
2018-09-01
NCT02852057
2021-08-10
Q6
At the median, Dorzolamide's trials enrolled 42 people — anything larger?
Median enrolment
42
Largest enrolment
437
Registered trials counted
16
Q7
What do 1190 spontaneous reports say about Dorzolamide — and not say?
These are reports people sent to a regulator. They do not show the medicine caused the reaction. Nobody counted how many people took the medicine and reported nothing. The same event can be reported more than once, and many reports are incomplete. News coverage, lawsuits and new warnings change how often people report. A count is not a rate and not a risk.
Dorzolamide appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 1190 reaction mentions were counted: treatment failure 416; eye irritation 168; intraocular pressure increased 125; ocular hyperaemia 98. FAERS via Open Targets · CHEMBL1201162 · 2026-06-24
Show the evidence
treatment failure
416
eye irritation
168
intraocular pressure increased
125
ocular hyperaemia
98
eye pain
89
hypersensitivity
85
4 more recorded rows
vision blurred
66
bradycardia
50
visual acuity reduced
50
eye pruritus
43
recorded 2026-06-24 · last checked 2026-09-04
Q8
Which 10 reactions does Dorzolamide's label not list?
ChEMBL 37 — CC BY-SA 3.0 Unported · ClinicalTrials.gov — US Government work · Open Targets 26.06 — CC0 · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work
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