Treatment of glaucoma

 

Glaucoma describes a group of disorders characterised by a loss of visual field associated with cupping of the optic disc and optic nerve damage. While glaucoma is generally associated with raised intra-ocular pressure, it can occur when the intra-ocular pressure is within the normal range. The commonest form

of glaucoma is primary open-angle glaucoma (chronic simple glaucoma; wide-angle glaucoma), where the obstruction is in the trabecular meshwork. The condition is often asymptomatic and the patient may present with significant loss of visual-field. Primary angle closure glaucoma (acute closed-angle glaucoma, narrow-angle glaucoma) results from blockage of aqueous humour flow into the anterior chamber and is a medical emergency. A topical beta-blocker or a prostaglandin analogue is commonly the drug of first choice. It may be necessary to combine these drugs or add others, such as miotics, sympathomimetics, and carbonic anhydrase inhibitors, to control intra-ocular pressure. For urgent reduction of intra-ocular pressure and before surgery, mannitol 20% (up to 500 mL) is given by slow intravenous infusion until the intra-ocular pressure has been satisfactorily reduced. Acetazolamide by intravenous injection can also be used for the emergency management of raised intra-ocular pressure.

 

Miotics

 

PILOCARPINE HYDROCHLORIDE:

Indications: treatment of open-angle glaucoma. Reduction of intraocular pressure occurs within a few minutes after application and lasts for four to eight hours. It is also used to antagonise the effects of short-acting mydriatics on the eye and is alternated with mydriatics to break adhesions between the iris and the lens.

Contraindications: Contra-indicated where constriction of the pupil is undesirable such as in acute iritis.

Dose and Administration: Two drops topically in the eye(s), three or four times daily.

 

Carbonic anhydrase inhibitors and systemic drugs

 

ACETAZOLAMIDE:

Indications: reduction of intra-ocular pressure in open-angle glaucoma, secondary glaucoma, and peri-operatively in angle-closure glaucoma; diuresis; epilepsy.

Contraindications: hypokalaemia, hyponatraemia, hyperchloraemic acidosis; severe hepatic impairment; renal impairment; sulphonamide hypersensitivity.

Dose and Administration: Glaucoma, by mouth or by intravenous injection, 0.25–1 g daily in divided doses.

 

DORZOLAMIDE:

Indications: raised intra-ocular pressure in ocular hypertension, open-angle glaucoma, pseudo-exfoliative glaucoma either as adjunct to beta-blocker or used alone in patients unresponsive to beta-blockers or if beta-blockers contra­indicated.

Contraindications: renal impairment; hyperchloraemic acidosis; pregnancy and breast-feeding.

Dose and Administration: Used alone, apply 3 times daily. With topical beta­blocker, apply twice daily.

 

Beta-blockers

 

TIMOLOL MALEATE:

Indications: Chronic open angle glaucoma, secondary glaucoma. Ocular hypertension.

Contraindications: Bronchial asthma, history of bronchial asthma or severe chronic obstructive pulmonary disease, sinus bradycardia, second and third degree AV block, overt cardiac failure, cardiogenic shock, and hypersensitivity to timolol maleate or other beta-blocking agents.

Dose and Administration: One drop into the affected eye(s) twice daily.

 

DORZOLAMIDE-TIMOLOL MALEATE:

Indications: Indicated in the treatment of elevated intraocular pressure (IOP) in patients with open-angle glaucoma or pseudoexfoliative glaucoma when topical beta-blocker monotherapy is not sufficient.

Contraindications: reactive airway disease, including bronchial asthma or a history of bronchial asthma, or severe chronic obstructive pulmonary disease. sinus bradycardia, second- or third-degree atrioventricular block, overt cardiac failure, cardiogenic shock. severe renal impairment (CrCl < 30 ml/min) or hyperchloraemic acidosis.

Dose and Administration: The recommended adult dose of dorzolamide – timolol eye drops is one drop in the affected eye(s) twice daily. Dorzolamide – timolol eye drops should be used at least 10 minutes before or after other eye drops that are being used.

 

BETAXOLOL HYDROCHLORIDE:

Indications: indicated for the reduction of elevated intraocular pressure in patients with ocular hypertension and chronic open angle glaucoma.

Contraindications: contraindicated in patients with sinus bradycardia greater than a first degree block, cardiogenic shock or a history of overt cardiac failure and in patients with hypersensitivity to any component.

Dose and Administration: The usual dose is one drop to be instilled into the affected eye(s) twice daily.

 

LEVOBUNOLOL HYDROCHLORIDE:

Indications: Reduction of intraocular pressure in chronic open-angle glaucoma and ocular hypertension.

Contraindications: Bronchial asthma; history of bronchial asthma; chronic obstructive pulmonary disease; sinus bradycardia; second and third degree atrioventricular block; cardiac failure; cardiogenic shock; hypersensitivity to any component; sick sinus syndrome (including sino-atrial block); Prinzmetal’s angina; untreated phaeochromocytoma; metabolic acidosis; hypotension.

Dose and Administration: The usual dose is one drop instilled in the affected eye(s) once or twice daily. In common with other topical ophthalmic beta­adrenergic blocking agents, full clinical response may take several weeks to occur. Intraocular pressure should therefore be measured approximately four weeks after starting treatment. Because of diurnal variations in intraocular pressure, satisfactory response is best determined by measuring the intraocular pressure at different times of the day.

 

Sympathomimetics

 

BRIMONIDINE TARTRATE:

Indications: indicated for lowering intraocular pressure in patients with chronic open-angle glaucoma or ocular hypertension, alone or in combination with other intraocular lowering medications.

Contraindications: contraindicated in patients with hypersensitivity to brimonidine tartrate or any component of this medication. It is also contraindicated in patients receiving monoamine oxidase (MAO) inhibitor therapy.

Dose and Administration: The recommended dose is one drop of BRIMONIDINE TARTRATE in the affected eye(s) twice daily, approximately 12 hours apart. If more that one topical ophthalmic drug is to be used, the different drugs should be instilled 5-15 minutes apart.

 

Prostaglandin analogues

 

BIMATOPROST:

Indications: Reduction of elevated intraocular pressure in chronic open-angle glaucoma and ocular hypertension.

Contraindications: Hypersensitivity to the active substance or to any of the excipients.

Dose and Administration: The recommended dose is one drop in the affected eye(s) once daily, administered in the evening. The dose should not exceed once daily as more frequent administration may lessen the intraocular pressure lowering effect. Use in children and adolescents (under the age of 18): BIMATOPROST has only been studied in adults and therefore its use is not recommended in children or adolescents.

 

BIMATOPROST-TIMOLOL:

Indications: Reduction of intraocular pressure (IOP) in open-angle glaucoma or ocular HTN.

Contraindications: Bronchial asthma or a history of bronchial asthma, severe COPD, sinus bradycardia, 2nd or 3rd degree AV block, overt cardiac failure, cardiogenic shock.

Dose and Administration: Instill 1 drop in the affected eye once daily.

 

LATANOPROST:

Indications: Reduction of elevated intraocular pressure in patients with open angle glaucoma, chronic angle closure glaucoma and ocular hypertension.

Contraindications: Known hypersensitivity to latanoprost, benzalkonium chloride or any other component. Use of all contact lenses.

Dose and Administration: Recommended therapy is one eye drop in the affected eye(s) once daily. Optimal effect is obtained if LATANOPROST is administered in the evening.

 

LATANOPROST-TIMOLOL:

Indications: Reduction of intraocular pressure (IOP) in patients with open angle glaucoma and ocular hypertension who are not controlled on, or are intolerant to, monotherapy with compounds other than latanoprost and timolol.

Contraindications: Reactive airway disease including bronchial asthma or a history of bronchial asthma, chronic obstructive pulmonary disease. Sinus bradycardia, second or third degree atrioventricular block, cardiac failure, cardiogenic shock. Hypersensitivity to any component of this product. Should not be used in breast-feeding women, or breast-feeding should be stopped as timolol is excreted into breast milk and latanoprost and its metabolites may pass into breast milk.

Dose and Administration: Recommended therapy is one drop in the affected eye(s) once daily. If more than one topical ophthalmic drug is being used, the drugs should be administered at least 5 minutes apart.

 

TRAVOPROST:

Indications: indicated for the reduction of elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension who are intolerant of or insufficiently responsive to another intraocular pressure lowering medication, as monotherapy or as adjunctive therapy.

Contraindications: Hypersensitivity to TRAVOPROST, benzalkonium chloride or any of the excipients. Pregnant women or women attempting to become pregnant as teratogenicity has been demonstrated in experimental animals. Breast-feeding women. Children, as safety and efficacy have not been proven.

Dose and Administration: The recommended dose is one drop of TRAVOPROST in the conjunctival sac of the affected eye(s) once daily in the evening.

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