Dosing and uses of Cosopt (timolol-dorzolamide)
Adult dosage forms and strengths
timolol/dorzolamide
ophthalmic solution
- 0.5%/2%
Open-Angle Glaucoma or Ocular Hypertension
Instill 1 gtt in affected eye(s) q12hr
Pediatric dosage forms and strengths
timolol/dorzolamide
ophthalmic solution
- 0.5%/2%
Open-Angle Glaucoma or Ocular Hypertension
<2 years
- Contraindicated
>2 years
- Instill 1 gtt in affected eye(s) q12hr
Cosopt (timolol-dorzolamide) adverse (side) effects
>10%
Dorzolamide
- Ocular burning, stinging, discomfort (33%)
- Bitter taste (25%)
- Superficial punctate keratitis (10-15%)
- Ocular allergic reactions (10%)
Frequency not defined
Dorzolamide
- Blurred vision
- Ocular dryness
- Photophobia
- Ocular redness
- Tearing
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis
TimoloL
- Arrythmia
- Bradycardia
- Syncope
- Fatigue
- Headache
- Dyspnea
- Bronchospasm
- Chest pain
- Edema
- Paresthesia
- Nausea
- Rales
- Depression
- Decreased exercise tolerance
- Raynaud's phenomenon
Warnings
Contraindications
Age <2 years
Hypersensitivity, asthma, severe COPD, sinus bradycardia, 2nd/3rd degree AV block (except in patients with artificial pacemaker), overt CHF, cardiogenic shock
Cautions
Dorzolamide (a sulfonamide) and, although administered topically, is absorbed systemically; same types of adverse reactions attributable to sulfonamides may occur with topical administration, including severe skin reactions
Bacterial keratitis associated with use of multiple-dose containers of topical ophthalmic products, inadvertently contaminated by patients who, in most cases, had concurrent corneal disease or disruption of ocular epithelial surface
Conjunctivitis reported with chronic administration (may resolve upon discontinuation of therapy)
Sympathetic stimulation may be essential for support of circulation in diminished myocardial contractility; its inhibition by beta-adrenergic receptor blockade may precipitate more severe failure; in patients without history of cardiac failure continued depression of myocardium with beta-blocking agents over a period of time can, in some cases, lead to cardiac failure; discontinue therapy at first sign or symptom of cardiac failure
Not for use as monotherapy in angle-closure glaucoma
Use caution in diabetes, heart failure, psychiatric disease (may cause or exacerbate CNS depression), peripheral vascular disease
Not for administration to patients with chronic obstructive pulmonary disease (e.g., chronic bronchitis, emphysema) of mild or moderate severity, bronchospastic disease, or a history of bronchospastic disease (other than bronchial asthma or a history of bronchial asthma, in which timiool is contraindicated)
Patients may be unresponsive to usual doses of epinephrine used to treat anaphylactic reactions; patients with a history of atopy or a history of severe anaphylactic reactions to a variety of allergens may be more reactive to repeated accidental, diagnostic, or therapeutic challenge with such allergens Increase muscle weakness in some patients with myasthenia gravis or myasthenic symptoms reported
Beta-adrenergic receptor blocking agents may mask signs and symptoms of acute hypoglycemia; administer with caution in patients subject to spontaneous hypoglycemia or to diabetic patients (especially those with labile diabetes) who are receiving insulin or oral hypoglycemic agents
Beta-adrenergic blocking agents may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism; manage carefully patients suspected of developing thyrotoxicosis to avoid abrupt withdrawal of beta-adrenergic blocking agents that might precipitate thyroid storm
Not studied in patients with severe renal impairment (CrCl <30 mL/min); not recommended; dorzolamide and its metabolite are excreted predominantly by kidney
Use with caution in hepatic impairment; not studed
Patients receiving beta-adrenergic receptor blocking agents have experienced protracted severe hypotension during anesthesia; difficulty in restarting and maintaining heartbeat has also reported; gradual withdrawal of beta-adrenergic receptor blocking agents recommended; the effects of beta-adrenergic blocking agents may be reversed by sufficient doses of adrenergic agonists if necessary
There is increased potential for developing corneal edema in patients with low endothelial cell counts; use caution
Avoid concomitant administration with systemic beta-blockers or carbonic anhydrase inhibitors
Use caution in patients taking calcium channel blockers, cardiac glycosides, or inhaled anesthetic agents
Pregnancy and lactation
Pregnancy category: C
Lactation: Excreted in breast milk; not recommended
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Cosopt (timolol-dorzolamide)
Mechanism of action
Dorzolamide: Sulfonamide and carbonic anhydrase inhibitor; inhibition of carbonic anhydrase in ciliary processes of the eye decreases aqueous humor secretion, presumably by slowing the formation of bicarbonate ions with subsequent reduction in sodium and fluid transport
Timolol: Nonselective beta-adrenergic receptor blocker; reduces IOP by reducing production of aqueous humor
