Topical glaucoma-drug classes and contraindications

01Purpose and principlesWhat the treatment does and how it fits into care.

A glaucoma prescription must fit the eye and the whole patient. Drug classes differ in mechanism, duration, systemic absorption and adverse effects, while specific formulations differ in concentration, preservative and dosing schedule. The fact that a medicine is instilled into the eye does not remove cardiac, respiratory, renal or interaction risks. A brand-name combination can conceal an ingredient that would have been avoided if prescribed separately.

Treatment selection sits within a plan for the diagnosis, target pressure and follow-up. It is reasonable to change a poorly tolerated medicine rather than repeatedly emphasise adherence to an unworkable regimen. Conversely, a pressure above target should not immediately trigger another bottle when the original drops are missing the eye or have run out. A useful medication review reconciles every bottle, observes administration, checks systemic medicines and agrees a practical schedule that can be followed over time.

Key points

Topical treatment lowers pressure by reducing aqueous production or improving outflow; the aim is to reduce future visual loss rather than restore damaged nerve tissue.
A prostaglandin analogue is commonly selected when initial SLT is unsuitable, declined, awaited with interim treatment needed, or insufficient.
Latanoprost 50 micrograms/mL is one drop per treated eye each evening; increasing the frequency can reduce its pressure-lowering effect.
Timolol is contraindicated with asthma or its history, severe COPD, important bradyarrhythmia, second- or third-degree AV block without pacemaker control, overt heart failure or cardiogenic shock.
Dorzolamide is contraindicated with creatinine clearance below 30 mL/min or hyperchloraemic acidosis; brimonidine has important antidepressant interactions and must not be used below age two years.
Fixed combinations retain every ingredient's contraindications and must be checked for duplicate beta-blockers or prostaglandin analogues.
NICE TA1009 places latanoprost–netarsudil after inadequate prostaglandin monotherapy when a subsequent fixed combination is insufficient or a beta-blocker-containing fixed combination is unsuitable.
Observe drop technique, address adverse effects and confirm actual administration before escalating an apparently ineffective prescription.

02Indications, selection and cautionsWho may benefit, who needs urgent treatment and important alternatives.

Prostaglandin effects

Iris darkening, lash growth and local hyperaemia may appear during treatment; pain or reduced vision warrants examination for inflammation, corneal problems or other pathology rather than automatic reassurance.

Systemic beta blockade

New wheeze, slow pulse, dizziness or worsening exercise tolerance after timolol can be drug related; include fixed combinations in the medication history.

Alpha-agonist intolerance

Brimonidine may cause dry mouth, fatigue, drowsiness or delayed ocular allergy, sometimes after months of initially satisfactory use.

Preservative or surface symptoms

Burning, dryness and irritation can undermine continued use; assess the ocular surface and the active drug as possible causes before selecting a different formulation.

Red flags requiring action

New wheeze or collapse after starting a timolol-containing drop requires urgent medical assessment; check combination bottles because the beta-blocker may not be obvious from the brand name.

03Assessment before treatmentTests and checks that guide safe selection.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Complete topical and systemic medication reconciliationFirst step
Why
Identify duplicate ingredients, interacting medicines and unintended continued prescriptions.
Interpretation and limitations
Read active ingredients and concentrations on actual containers; stopping a separate timolol bottle may still leave timolol exposure through a fixed combination.
02
Cardiorespiratory history and targeted examination
Why
Screen for contraindications before a beta-blocker or relevant alpha agonist.
Interpretation and limitations
Ask directly about asthma, COPD, syncope, conduction disease and heart failure; assess pulse and other investigations when symptoms or history indicate a need rather than imposing universal ECG testing.
03
Renal, metabolic and reproductive assessment when relevant
Why
Select medicines safely in circumstances that alter risk.
Interpretation and limitations
Severe renal impairment affects carbonic anhydrase inhibitor suitability; pregnancy, breastfeeding, age and interacting medicines require the specific product information and specialist advice.
04
Pressure, ocular surface and observed instillation
Why
Determine therapeutic response and whether the prescribed dose reaches the eye.
Interpretation and limitations
Compare with the treatment target and baseline, inspect for surface intolerance and watch technique before distinguishing insufficient pharmacological effect from incomplete delivery.

04Treatment approachPreparation, options, escalation and aftercare.

01Starting treatmentMatch the medicine to the patientFirst stepA glaucoma clinician selects topical therapy after considering diagnosis, laser suitability and visual risk.

1Confirm which eye needs treatment, the intended pressure goal and the medical or ocular factors that exclude particular classes.
2Choose an appropriate agent and formulation, state dose and timing clearly, and demonstrate bottle handling and measures that limit drainage into the nose.
3Arrange a response review and explain which local effects can be expected and which systemic or ocular symptoms require urgent contact.

02Insufficient responseCheck delivery before adding another classMeasured pressure remains above the agreed target despite a prescribed topical regimen.

1Ask about missed doses without judgement, confirm supply and expiry, and observe whether a single drop actually enters the lower conjunctival pocket.
2Review tolerability, interactions and duplication, then consider a different therapeutic class, a suitable combination, laser or surgery with the glaucoma team.
3Provide a reconciled written schedule and remove superseded prescriptions so the new plan does not unintentionally add duplicate active ingredients.

03Adverse effectsReplace a harmful or intolerable regimenNew systemic symptoms, ocular allergy or troublesome surface disease develops during glaucoma treatment.

1Assess the severity and obtain urgent medical or ophthalmic care for significant respiratory, cardiac, allergic or visual symptoms.
2Identify the suspected ingredient and review all combination products, withholding a likely harmful medicine while the responsible team arranges suitable pressure cover.
3For non-emergency intolerance, consider another class or appropriate preservative-free preparation and review both comfort and pressure after the change.

05Regimens, contraindications and interactionsTreatment details and the circumstances that modify them.

Prostaglandin analogue that increases aqueous outflow for sustained pressure reduction.

Latanoprost 50 micrograms/mL

Apply one drop to the affected eye or eyes once each day, preferably in the evening, as continuing treatment until reviewed; if a dose is missed, resume the next scheduled dose.

More frequent dosing is not recommended, and another prostaglandin analogue should not be added. Counsel about iris pigmentation and lash changes; assess uveitis, herpetic keratitis and macular-oedema risks. The Xalatan product information advises against use during pregnancy and breastfeeding.

Non-selective beta-blocker that reduces aqueous humour production when clinically suitable.

Timoptol timolol standard aqueous drops

The standard Timoptol product starts with one drop of 0.25% in the treated eye twice daily; if inadequate, 0.5% twice daily may be used. Review pressure at about four weeks and continue or reduce frequency only on instruction.

Do not confuse this with once-daily gel-forming products. Avoid asthma or previous asthma, severe COPD, sinus bradycardia, sick-sinus or sinoatrial block, unpaced second- or third-degree AV block, overt heart failure and cardiogenic shock. Other beta-blockers and rate-limiting cardiac medicines can add to systemic effects.

Topical carbonic anhydrase inhibition reduces aqueous secretion and can supplement another drug class.

Dorzolamide 20 mg/mL

For the selected single-agent product, monotherapy is one drop three times daily in each affected eye; adjunctive use with an ophthalmic beta-blocker is one drop twice daily, with ongoing treatment determined by pressure review.

Avoid use with creatinine clearance under 30 mL/min or hyperchloraemic acidosis. Consider sulphonamide-associated reactions, renal-stone history and corneal endothelial disease. Its SmPC advises against concurrent oral carbonic anhydrase inhibitors and specifies at least ten minutes between topical eye medicines.

Alpha-2 agonist used for additional pressure reduction or when a beta-blocker is contraindicated.

Alphagan brimonidine 0.2% (2 mg/mL)

Instil one drop into the affected eye or eyes twice daily, approximately twelve hours apart, and continue only while effective and tolerated with scheduled review.

Contraindicated below age two and with MAO inhibitors or antidepressants affecting noradrenergic transmission, including tricyclics and mianserin; not recommended below age twelve. Consider hypotension, somnolence and cardiovascular insufficiency, and stop for allergy. The product should not be used during breastfeeding.

Combines prostaglandin-mediated outflow effects with Rho-kinase inhibition for eligible previously treated disease.

Roclanda latanoprost 50 micrograms/mL plus netarsudil 200 micrograms/mL

An appropriately qualified ophthalmic professional initiates one drop in each affected eye once daily in the evening, never more than once per day; continue to the planned efficacy and tolerability review.

Do not retain a separate prostaglandin analogue. Use other eye drops first, separated by at least five minutes, and ointment last. Hyperaemia and corneal verticillata are common; new pain or reduced vision needs assessment for reticular epithelial corneal oedema, particularly after surgery or with existing oedema. Avoid use during pregnancy.

06Complications, monitoring and follow-upAdverse effects, response and longer-term review.

Assess pressure response alongside the underlying glaucoma status rather than treating a lower reading as sufficient evidence that progression has stopped.
Ask about respiratory symptoms, dizziness, drowsiness, pulse-related symptoms and ocular allergy at follow-up, particularly after introducing a new class.
Reassess technique when the bottle changes, dexterity deteriorates or a carer takes over; different containers may require different squeezing force and handling.
Review the continued need for each ingredient after laser or surgery and communicate an explicit stop or continuation instruction to the person and usual prescriber.

07Special situationsVariants, exceptions and circumstances that change the usual approach.

Absorption reduction is product specific

Gentle eyelid closure or punctal occlusion after a drop can reduce systemic exposure. Xalatan and Alphagan specify one minute, whereas the standard Timoptol and selected dorzolamide information use two minutes. This does not make a contraindicated medicine safe.

Bottle count is not treatment intensity

One fixed-combination bottle may contain two active drugs, while several bottles may duplicate a class. Build a list by active ingredient, then check whether the proposed combination adds a useful mechanism and an acceptable adverse-effect burden.

Licence and NHS recommendation differ

Roclanda's marketing authorisation and NICE's funding recommendation answer different questions. TA1009 requires insufficient prostaglandin monotherapy plus an unsuccessful subsequent fixed combination or unsuitability of a beta-blocker-containing fixed combination; initial prescribing must meet the relevant criteria.

Miotics have a mechanism-dependent role

Pilocarpine changes pupil and ciliary muscle activity and is not a default solution for every high pressure. Its role is particularly dependent on angle anatomy, and it can aggravate lenticular or retrolenticular closure. Brow ache and altered vision can also limit long-term acceptability.

Preservative-free does not mean risk-free

Removing a preservative can help selected ocular surface problems or allergy, but the active medicine retains its systemic and ocular contraindications. NICE's preservative-free recommendation also depends on diagnosis and, in ocular hypertension, high conversion risk.

Pregnancy and breastfeeding affect selection

Plan pressure treatment with ophthalmology when pregnancy or breastfeeding is relevant. The selected dorzolamide SmPC advises against pregnancy use and requires a decision between breastfeeding and treatment; Timoptol should be used in pregnancy only when clearly necessary, with neonatal monitoring if continued until delivery. Brimonidine requires a maternal benefit–fetal risk judgement and should not be used during breastfeeding. Roclanda also requires a breastfeeding-versus-treatment decision.

08Common pitfallsFrequent interpretation and management errors.

01
Prescribing a timolol combination to a person with asthma because the product is an eye drop.
02
Using a generic twice-daily schedule for every timolol formulation without reading the selected product.
03
Increasing a prostaglandin analogue above once daily to compensate for an inadequate pressure response.
04
Adding another bottle before checking adherence, administration, interactions and duplicate ingredients.
05
Dismissing new corneal pain or visual loss during netarsudil treatment as harmless redness.