Dorzolamide Hcl (dorzolamide HCl)

Dosage and concentration of dorzolamide hydrochloride are expressed in terms of dorzolamide.

For the treatment of open-angle glaucoma or ocular hypertension in adults and pediatric patients, the usual dosage of dorzolamide is 1 drop of a 2% ophthalmic solution in the affected eye(s) 3 times daily.

If the target intraocular pressure (IOP) is not achieved, alternative or additional ocular hypotensive agents may be required. (See Uses: Ocular Hypertension and Glaucoma.) When dorzolamide is used in fixed combination with timolol for the treatment of open-angle glaucoma or ocular hypertension in adults and pediatric patients 2 years of age or older, the usual dosage is 1 drop of an ophthalmic solution containing dorzolamide 2% and timolol 0.5% in the affected eye(s) twice daily. Because of the potential for additive systemic effects, combined use of topical dorzolamide and an oral carbonic anhydrase inhibitor (e.g., acetazolamide, dichlorphenamide, methazolamide) is not recommended by the manufacturer.

Topical dorzolamide has not been evaluated in patients with severe renal impairment (i.e., creatinine clearance less than 30 mL/minute). Because dorzolamide and N-desethyldorzolamide are eliminated principally via renal excretion, the manufacturer states that topical ocular use of the drug in patients with severe renal impairment is not recommended.

Topical dorzolamide has not been evaluated in patients with hepatic impairment, and the manufacturer states that the drug should be used with caution in such patients.

Dorzolamide hydrochloride is applied topically to the eye as an ophthalmic solution. Dorzolamide hydrochloride also is commercially available in fixed combination with timolol maleate for topical application to the eye as an ophthalmic solution.

Care should be taken to avoid contamination of the solution container. (See Cautions: Precautions and Contraindications.)

Dorzolamide ophthalmic solution and some formulations of dorzolamide and timolol ophthalmic solution contain benzalkonium chloride, which may be absorbed by soft contact lenses. Contact lenses should be removed prior to topical application of each dose of these preparations, but may be reinserted 15 minutes after the dose.

Preservative-free dorzolamide and timolol ophthalmic solution in single-use containers should be administered topically to one or both eyes immediately after the container is opened; since sterility cannot be maintained after the individual unit is opened, any remaining contents should be discarded immediately after administration.

If the patient is receiving more than one ophthalmic preparation, the preparations should be administered at least 5 minutes apart.

There is no enhanced messaging for this drug.

There are no contraindication interactions for this drug.

There are no severe interactions for this drug.

Moderate Interaction: Assess the risk to the patient and take action as needed.

Dorzolamide/Carbonic Anhydrase Inhibitors

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Dorzolamide and other carbonic anhydrase inhibitors cause a decrease in aqueous humor secretion by slowing the formation of bicarbonate ions with a subsequent reduction of sodium and fluid transport which results in a reduction of intraocular pressure.(1)

CLINICAL EFFECTS: If dorzolamide is given with other carbonic anhydrase inhibitors it may cause electrolyte disturbances, because dorzolamide can be absorbed systemically.(1)

PREDISPOSING FACTORS: Patients with conditions that predispose to acidosis (such as renal disease, severe respiratory disorders, status epilepticus, diarrhea, and being on a ketogenic diet) may be at increased risk of experiencing adverse effects from concurrent carbonic anhydrase inhibitors.

PATIENT MANAGEMENT: The manufacturer of dorzolamide states that concurrent use with oral carbonic anhydrase inhibitors is not recommended.(1)

DISCUSSION: Although no human data is available, electrolyte imbalance, development of an acidotic state, and possible nervous system effects may occur following administration of dorzolamide and oral carbonic anhydrase inhibitors.(1)

There is no enhanced messaging for this drug.

There are no contraindication contraindications for this drug.

There are no severe contraindications for this drug.

• No disease contraindications

There is no enhanced messaging for this drug.

More Frequent

• Ocular itching

Less Frequent

• Conjunctivitis

Rare or Very Rare

• Agranulocytosis
• Angioedema
• Aplastic anemia
• Bronchospastic pulmonary disease
• Choroidal detachment
• Contact dermatitis
• Dyspnea
• Epistaxis
• Hepatic necrosis
• Iridocyclitis
• Myopia
• Ocular pain
• Paresthesia
• Skin rash
• Sore throat
• Stevens-johnson syndrome
• Toxic epidermal necrolysis
• Urolithiasis

More Frequent

• Dysgeusia
• Ocular irritation
• Punctate keratitis

Less Frequent

• Blurred vision
• Dry eye
• Eye tearing
• Ocular redness
• Photophobia

Rare or Very Rare

• Dizziness
• Eyelid crusting
• General weakness
• Headache disorder
• Nausea
• Xerostomia

No enhanced messaging available.

No enhanced messaging available.

Reproduction studies in rabbits using oral dorzolamide at dosages that resulted in estimated peak plasma concentrations that were 37 times higher than the lower limit of detection in human plasma following ocular administration revealed malformations of the vertebral bodies. These malformations occurred at dosages that caused metabolic acidosis and decreased body weight gain in dams and decreased fetal weight. Reproductive studies in rabbits using oral dorzolamide at dosages that resulted in estimated peak plasma concentrations that were 15 times higher than the lower limit of detection in human plasma following ocular administration did not reveal evidence of teratogenic effects or embryotoxicity.

There are no adequate and controlled studies to date using dorzolamide in pregnant women, and the drug should be used during pregnancy only when the potential benefits justify the possible risks to the fetus.

In lactating rats given oral dorzolamide at dosages that resulted in estimated peak plasma concentrations that were 52 times higher than the lower limit of detection in human plasma following ocular administration, decreases of 5-7% in body weight gain in offspring and developmental delay (i.e., incisor eruption, vaginal canalization, eye opening) secondary to lower fetal body weight have been reported.

It is not known whether dorzolamide is distributed into human milk. Because of the potential for serious adverse reactions to dorzolamide in nursing infants, a decision should be made whether to discontinue nursing or the drug, taking into account the importance of the drug to the woman.

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