Dorzolamide

Registered South African indications:

• Open angle glaucoma
• Ocular hypertension
• Pseudoexfoliative glaucoma and other secondary open angle glaucomas
• Paediatric glaucomas (short-term)

Contraindications

• Hypersensitivity to the active ingredient or any of its excipients
• Severe renal impairment (CrCl <30ml/min)
• Hypercholaraemic acidosis

Caution

• Pregnancy
• Breastfeeding
• Mild to moderate renal impairment (CrCl >30ml/min)
• Hepatic impairment
• Acute closed angle glaucoma
• History of renal calculi
• Pre-existing chronic corneal defects
• History of intraocular surgery
• Patients <36 weeks gestational age and less than 1 week of age
• Concomitant use of contact lenses
• May impair ability to drive or operate machinery

Forms avail. in SA and covered in this monograph: opd

Open angle glaucoma
Ocular hypertension
Pseudoexfoliative glaucoma and other secondary open angle glaucomas

Monotherapy

• Ophthalmic (opd): Apply 1 drop to affected eye(s), 8hrly

Adjunctive therapy

• Ophthalmic (opd): Apply 1 drop to affected eye(s), 12hrly

Use as monotherapy in patients unresponsive to beta-blockers or in whom beta-blockers are contraindicated

If more than one topical ophthalmic medication is being used, the medicines should be administered at least 10 minutes apart

When substituting dorzolamide for another ophthalmic anti-glaucoma agent, discontinue the other agent after proper dosing on one day, and start dorzolamide on the next day

Contact lenses should be removed prior to application and wait at least 15 mins before reinsertion

See additional prescribing points

See adult dosage

Limited clinical data in paediatric patients with three times a day administration are available

Pregnancy 

• Caution
• Dorzolamide should not be used during pregnancy. There is no or limited amount of data from the use of dorzolamide in pregnant women
• In rabbits, dorzolamide produced teratogenic effects at maternotoxic doses

Breastfeeding

• Caution; not recommended
• It is unknown whether dorzolamide/metabolites are excreted in human milk. Available pharmacodynamic/toxicological data in animals have shown excretion of dorzolamide/metabolites in milk
• A decision must be made whether to discontinue breastfeeding or to discontinue/abstain from dorzolamide therapy taking into account the benefit of breastfeeding for the child and the benefit of therapy for the woman
• A risk to newborns/infants cannot be excluded

Fertility

• Animal data does not suggest an effect of treatment with dorzolamide on male and female fertility. Human data is lacking

Renal Impairment

• CrCl >30ml/min: Caution; no information available
  Monitor neonates and elderly patients carefully
  If significant renal tubular immaturity exists in neonates, the risk benefit balance should be carefully considered because of the possible risk of metabolic acidosis
• CrCl <30ml/min: Contraindicated

Hepatic Impairment

• Caution; no information available

Elderly

• No dose adjustment recommended

Porphyria Information

• Probably not porphyrinogenic (PNP)

Drugs in Sport

• Permitted - No warnings

Central Nervous System Disorders

• Headache
• Dizziness
• Paraesthesia
• Asthenia

Cardiovascular Disorders

• Palpitations

Respiratory Disorders

• Epistaxis
• Dyspnoea

Gastrointestinal Disorders

• Nausea
• Throat irritation
• Dry mouth

Genitourinary Disorders

• Urolithiasis

Skin and Subcutaneous Tissue Disorders

• Contact dermatitis
• Stevens-Johnson syndrome
• Toxic epidermal necrolysis

Immune, Blood and Lymphatic Disorders

• Hypersensitivity reactions
  - Angioedema
  - Urticaria
  - Pruritis
  - Rash
  - Dyspnoea
  - Bronchospasm

Sensory Disorders

• Burning eyes
• Stinging eyes
• Superficial punctate keratitis
• Tearing
• Conjunctivitis
• Eyelid inflammation
• Eye itching
• Eyelid irritation (redness, pain)
• Blurred vision
• Iridocyclitis
• Eye irritation
• Eyelid crusting
• Transient myopia
• Corneal oedema
• Ocular hypotony
• Choroidal detachment
• Foreign body sensation in eye
• Bitter taste

Oral carbonic anhydrase inhibitors

• Intraocular pressure

Administration directions

1. Hands should be washed before administration
2. Patient's head should be tilted back and the lower eyelid pulled down slightly to form a pocket between the eyelid and eye
3. After instillation, the used single-dose container should be discarded even if there is solution remaining
4. The remaining single-dose containers must be used within 15 days after opening of the sachet

Special precautions

• Patients with a history of contact hypersensitivity to silver should not use this product as dispensed drops may contain traces of silver from the container closure

Carbonic anhydrase (CA) is an enzyme found in many tissues of the body including the eye. In humans, carbonic anhydrase exists as a number of isoenzymes, the most active being carbonic anhydrase II (CA-II) found primarily in red blood cells (RBCs) but also in other tissues. Inhibition of carbonic anhydrase in the ciliary processes of the eye decreases aqueous humour secretion. The result is a reduction in intraocular pressure (IOP). Dorzolamide hydrochloride is a potent inhibitor of human carbonic anhydrase II. Following topical ocular administration, dorzolamide reduces elevated intraocular pressure, whether or not associated with glaucoma. Dorzolamide does not cause pupillary constriction and reduces intraocular pressure without side effects such as night blindness, accommodative spasm. Dorzolamide has minimal or no effect on pulse rate or blood pressure.

Eye drops (per ml) 20mg

• Glaucopress (Actor)
• Trusopt (Mundipharma) originator

COMBINATION PREPARATIONS

Dorzolamide/ Timolol

Eye drops (per ml) 20mg/5mg

• Cosopt (Mundipharma) originator
• Glaumide Co (Actor) 
• Glauopt Co (Pharmacare)