Dorzolamide-Timolol (dorzolamide HCl/timolol maleate/PF)

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.

Timolol or timolol maleate is applied topically to the eye as an ophthalmic solution. Timolol maleate also is applied topically to the eye as a gel-forming ophthalmic solution. Timolol maleate also is commercially available in fixed combination with dorzolamide hydrochloride or brimonidine tartrate (as ophthalmic solutions) for topical application to the eye. Care should be taken to avoid contamination of the solution container.

Some timolol ophthalmic solutions contain benzalkonium chloride, which may be absorbed by soft contact lenses. Contact lenses should be removed prior to administration of each dose of these solutions, but may be reinserted 15 minutes after the dose.

Preservative-free ophthalmic solutions containing timolol alone or in fixed combination with dorzolamide should be administered topically to one or both eyes immediately after the single-use 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, although some manufacturers recommend an interval of at least 10 minutes. Containers of timolol maleate ophthalmic gel-forming solution should be inverted and shaken once just prior to administration of each dose. Patients receiving ophthalmic gel-forming solutions of the drug who also are receiving other ophthalmic preparations should be instructed that other topical preparations be administered at least 10 minutes before a dose of the gel-forming solution.

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.

No dosing information is available for this tab.

No dosing information is available for this tab.

There is no enhanced messaging for this drug.

There are no contraindication interactions for this drug.

There are no severe interactions for this drug.

There are no moderate interactions for this drug.

There is no enhanced messaging for this drug.

There are no contraindication contraindications for this drug.

There are no severe contraindications for this drug.

There are no moderate contraindications for this drug.

There is no enhanced messaging for this drug.

There are no severe adverse reactions for this drug.

There are no less severe adverse reactions for this drug.

No enhanced messaging available.

No enhanced messaging available.

Reproduction studies in mice, rats, and rabbits using oral timolol dosages up to 50 mg/kg daily (7000 times the systemic exposure following the maximum recommended human ophthalmic dosage) have not revealed evidence of harm to the fetus. Although delayed fetal ossification was observed at this dosage in rats, no adverse effects on postnatal development occurred in this species. Oral timolol dosages of 1 g/kg daily (142,000 times the systemic exposure following the maximum recommended human ophthalmic dosage) were maternotoxic and resulted in an increased number of fetal resorptions in mice. Increased fetal resorptions were also observed in rabbits receiving oral timolol dosages 14,000 times the systemic exposure following the maximum recommended human ophthalmic dosage.

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

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.

Timolol is distributed into milk following oral or topical ophthalmic administration. Because of the potential for serious adverse reactions from timolol 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.

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.

No enhanced messaging available.