BETAGAN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BETAGAN (BETAGAN).
Beta-1 selective beta-adrenergic receptor antagonist; reduces intraocular pressure by decreasing aqueous humor production.
| Metabolism | Primarily hepatic via CYP2D6; active metabolite: 4-hydroxybetaxolol. |
| Excretion | Primarily renal excretion of unchanged drug and metabolites; about 80% eliminated in urine, 20% in feces as unchanged drug or glucuronide conjugates. |
| Half-life | Terminal elimination half-life is approximately 10-15 hours in adults; prolonged in renal impairment (up to 30 hours). |
| Protein binding | Approximately 30% bound to plasma proteins (mainly albumin). |
| Volume of Distribution | 0.5-1.0 L/kg; indicates distribution into total body water. |
| Bioavailability | Ophthalmic: Systemic absorption is low (<20%) due to limited corneal penetration and nasolacrimal drainage; oral: approximately 90%. |
| Onset of Action | Ophthalmic: 30 minutes; significant reduction in intraocular pressure within 1-2 hours. |
| Duration of Action | Ophthalmic: 12-24 hours; intraocular pressure reduction persists for 24 hours with twice-daily dosing. |
Instill 1 drop of 0.25% or 0.5% solution into the affected eye(s) twice daily.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No dosage adjustment necessary for renal impairment. |
| Liver impairment | Use with caution in hepatic impairment; no specific dose adjustment guidelines available, but consider reduced dosing due to potential for increased systemic effects. |
| Pediatric use | Not established; use not recommended in pediatric patients. |
| Geriatric use | No specific dose adjustment required; use lowest effective concentration and monitor for systemic beta-blocker side effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BETAGAN (BETAGAN).
| Breastfeeding | Betaxolol is excreted in human milk with an estimated M/P ratio of approximately 5:1. Due to potential for serious adverse reactions in nursing infants (e.g., bradycardia, hypotension), consider discontinuing breastfeeding or drug, taking into account importance to mother. |
| Teratogenic Risk | Betaxolol ophthalmic solution (BETAGAN) is a beta-blocker. Systemic absorption is low. No adequate studies in pregnant women. Beta-blockers may cause fetal bradycardia, intrauterine growth restriction, and hypoglycemia, especially during the second and third trimesters. Use only if potential benefit justifies risk. |
■ FDA Black Box Warning
None
| Serious Effects |
["Sinus bradycardia","Greater than first-degree AV block","Cardiogenic shock","Overt cardiac failure","Hypersensitivity to betaxolol or any component","Bronchial asthma (relative contraindication)"]
| Precautions | ["Cardiac failure: can precipitate or worsen CHF","Bronchospasm: caution in patients with asthma or COPD","Anaphylactic reactions: may block epinephrine effects","Thyrotoxicosis: may mask signs of hyperthyroidism","Myasthenia gravis: may exacerbate muscle weakness","Sulfite sensitivity: contains sulfites; caution in asthmatics"] |
| Food/Dietary | No significant food interactions. Limit alcohol intake as it may increase systemic side effects like dizziness or drowsiness. |
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| Fetal Monitoring | Monitor maternal heart rate and blood pressure. In neonates, monitor for signs of beta-blockade (bradycardia, hypoglycemia) for 48-72 hours after delivery if used near term. |
| Fertility Effects | No specific studies on fertility effects in humans; animal studies showed no impairment of fertility at relevant doses. |
| Clinical Pearls | Betagan (levobunolol) is a non-selective beta-blocker used ophthalmically for glaucoma. Monitor for systemic beta-blockade effects, especially bradycardia and bronchospasm in susceptible patients. Use with caution in patients with sinus bradycardia, AV block, or reactive airway disease. Can mask symptoms of hypoglycemia and hyperthyroidism. Assess intraocular pressure regularly; if inadequate response, consider additive therapy. Discontinue gradually if switching to another beta-blocker due to risk of withdrawal effects. |
| Patient Advice | Apply one drop to the affected eye(s) once or twice daily as prescribed. · Do not touch the dropper tip to any surface, including the eye, to avoid contamination. · Wait at least 5 minutes between applying different eye medications. · May cause temporary blurred vision; avoid driving or operating machinery until clear. · Report any slow heart rate, difficulty breathing, or unusual fatigue to your doctor. · Inform all healthcare providers that you use this medication, especially before surgery. · Do not stop using without consulting your doctor, as abrupt discontinuation may worsen glaucoma. |