Betaxolol Hcl (betaxolol HCl)

Although USP currently states that potency of betaxolol hydrochloride preparations should be expressed both in terms of the salt and the base (''active moiety''), dosage currently is expressed in terms of the base. (See Chemistry and Stability: Chemistry.)

For the treatment of open-angle glaucoma or ocular hypertension, the therapeutic regimen must be adjusted to the individual requirements and response of the patient as determined by tonometric readings before and during therapy.

For the initial treatment of open-angle glaucoma or ocular hypertension in adults, the usual dosage of betaxolol is 1 or 2 drops of the 0.5% ophthalmic solution or 1 drop of the 0.25% resin-formulated ophthalmic suspension in the affected eye(s) twice daily. When betaxolol is used for the treatment of open-angle glaucoma or ocular hypertension in pediatric patients, the usual dosage is 1 drop of the 0.25% resin-formulated suspension in the affected eye(s) twice daily.

Because of diurnal variations, it has been suggested that intraocular pressure (IOP) be measured at different times during the day to determine if an adequate hypotensive effect is maintained in patients receiving twice-daily therapy. IOP may not stabilize for a few weeks after initiating betaxolol therapy in some patients.

If the target IOP is not achieved, alternative or additional ocular hypotensive agents may be required. (See Uses: Ocular Hypertension and Glaucoma.)

Betaxolol hydrochloride is applied topically to the eye as an ophthalmic solution or resin-formulated suspension. Care should be taken to avoid contamination of the dispensing container. (See Cautions: Precautions and Contraindications.) The resin-formulated suspension should be shaken well prior to use.

Patients receiving the resin-formulated suspension should be advised to administer any concomitant topical ophthalmic drugs at least 10 minutes before administering the suspension.

Betaxolol hydrochloride ophthalmic solution and the resin-formulated suspension contain benzalkonium chloride, which may be absorbed by soft contact lenses. Contact lenses should be removed prior to administration of each betaxolol dose, but may be reinserted 15 minutes after the dose.

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.

Beta-Blockers/Clonidine

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

MECHANISM OF ACTION: Withdrawal of clonidine triggers increased catecholamine release. Beta-blockers inhibit the vasodilation mediated by the beta 2 receptor, leaving the vasoconstriction mediated by the alpha 2 receptor unopposed. In addition, concurrent use is expected to produce additive effects on blood pressure and heart rate requiring standard monitoring precautions.

CLINICAL EFFECTS: Severe hypertension may occur upon abrupt discontinuation of clonidine in patients receiving both clonidine and beta-blockers. In addition, concurrent use is expected to produce additive effects on blood pressure and heart rate requiring standard monitoring precautions.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: In a patient receiving both drugs, discontinuation of the beta-blocker prior to clonidine may decrease the occurrence of rebound hypertension. If clonidine is discontinued first, rebound hypertension can be treated by restarting the clonidine or by the IV administration of phentolamine, phenoxybenzamine or prazosin. When adding either of these agents to the drug regimen of the patient, monitor blood pressure. Since labetalol has both alpha and beta activity, administration of labetalol may prevent rebound hypertension in patients undergoing clonidine withdrawal, although conflicting reports exist. In addition, concurrent use is expected to produce additive effects on blood pressure and heart rate requiring standard monitoring precautions.

DISCUSSION: Increased blood pressure has been observed in patients following: 1) the discontinuation of clonidine in patients receiving beta-blockers, 2) the replacement of clonidine therapy with beta-blockers, 3) the simultaneous discontinuation of both drugs. Conflicting reports exist on the development of increased blood pressure after clonidine withdrawal in patients receiving labetalol. Patients receiving labetalol who are being withdrawn from clonidine should still be closely monitored.

Beta-Blockers/Moxonidine

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

MECHANISM OF ACTION: Withdrawal of moxonidine triggers increased catecholamine release. Beta-blockers inhibit the vasodilation mediated by the beta 2 receptor, leaving the vasoconstriction mediated by the alpha 2 receptor unopposed. In addition, concurrent use is expected to produce additive effects on blood pressure and heart rate requiring standard monitoring precautions.

CLINICAL EFFECTS: Severe hypertension may occur upon abrupt discontinuation of moxonidine in patients receiving both moxonidine and beta-blockers. In addition, concurrent use is expected to produce additive effects on blood pressure and heart rate requiring standard monitoring precautions.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: If combination therapy with moxonidine and a beta-blocker is to be ceased, the beta-blocker should be stopped first to decrease the risk of rebound hypertension. Moxonidine may be stopped after a few days have elapsed. During cessation of therapy blood pressure should be regularly monitored. If moxonidine is discontinued first, rebound hypertension can be treated by restarting the moxonidine or by the IV administration of phentolamine, phenoxybenzamine or prazosin. Since labetalol has both alpha and beta activity, administration of labetalol may prevent rebound hypertension in patients undergoing moxonidine withdrawal, although conflicting reports exist. When adding either of these agents to the drug regimen of the patient, monitor blood pressure. Concurrent use is expected to produce additive effects on blood pressure and heart rate requiring standard monitoring precautions.

DISCUSSION: Abrupt cessation of combination therapy with moxonidine and a beta-blocker may result in rebound hypertension. Withdrawal of moxonidine may trigger increased catecholamine release. Beta-blockers inhibit the vasodilation mediated by the beta 2 receptor, leaving the vasoconstriction mediated by the alpha 2 receptor unopposed.

There is no enhanced messaging for this drug.

• Acute decompensated heart failure
• Cardiogenic shock
• Heart block
• Sinus bradycardia

There are no severe contraindications for this drug.

• Asthma
• Chronic heart failure
• Chronic obstructive pulmonary disease
• Diabetes mellitus
• Hypoglycemic disorder
• Myasthenia gravis

There is no enhanced messaging for this drug.

Rare or Very Rare

• Acute cognitive impairment
• Alopecia
• Anisocoria
• Bradycardia
• Cardiac arrhythmia
• Chronic heart failure
• Corneal staining
• Cough
• Decreased corneal sensitivity
• Depression
• Dizziness
• Dyspnea
• Fatigue
• Glossitis
• Headache disorder
• Heart block
• Insomnia
• Keratitis
• Palpitations
• Pruritus of skin
• Punctate keratitis
• Skin rash
• Syncope
• Toxic epidermal necrolysis
• Urticaria
• Wheezing

More Frequent

• Ocular irritation

Rare or Very Rare

• Ocular itching
• Ocular redness
• Photophobia

No enhanced messaging available.

No enhanced messaging available.

Reproduction studies in rats using oral betaxolol dosages of 4, 40, or 400 mg/kg daily (more than 300, 3000, or 30,000 times the recommended human daily ocular dose, respectively) and in rabbits using oral dosages of 1, 4, 12, and 36 mg/kg daily have not revealed evidence of teratogenicity. There are no adequate and well-controlled studies to date using betaxolol hydrochloride ophthalmic solution or resin-formulated suspension in pregnant women, and the drug should be used during pregnancy only when the potential benefits justify the possible risks to the fetus.

Since betaxolol is distributed into milk, the drug should be used with caution in nursing women. Although betaxolol concentrations in milk may be up to 3 times those in maternal blood, it is unlikely that clinically important doses of the drug would be ingested by breast-fed infants during ophthalmic use of usual betaxolol dosages in the woman.

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