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BETAXOLOL HYDROCHLORIDE

Medical Diagnosis and Drugs, Medications
BETAXOLOL HYDROCHLORIDE
(be-tax'oh-lol)
Betoptic, Betoptic-S, Kerlone
Classifications: eye preparation; miotic (antiglaucoma agent); beta-adrenergic blocker; antihypertensive agent;
Therapeutic: antiglaucoma agent (miotic); antihypertensive agent
Prototype: Propranolol
Pregnancy Category: C

Availability

10 mg, 20 mg tablets; 0.25%, 0.5% ophthalmic solution

Action

Acts as a beta1-selective adrenergic receptor blocking agent, especially in the cardioselective beta1 receptors. Its antihypertensive effect is thought to be due to: (1) decreasing cardiac output, (2) reducing sympathetic nervous system outflow to the periphery resulting in vasodilatation, and (3) suppression of renin activity in the kidney. It reduces intraocular pressure within the eye by decreasing the production of aqueous humor.

Therapeutic Effect

All three mechanisms result in its antihypertensive effect.

Uses

Hypertension. Ocular use for intraocular hypertension, chronic open angle glaucoma (see Appendix A-1).

Contraindications

Sinus bradycardia, AV block greater than first degree, cardiogenic shock, severe left ventricular heart failure; glaucoma, angle closure (unless with a miotic); pregnancy (category C); children <18 y.

Cautious Use

Concomitant use of systemic beta-adrenergic blocking agents; history of heart failure; renal impairment, elderly; hyperthyroidism or thyrotoxicosis; diabetes mellitus; with evidence of airflow obstruction or reactive airway disease; depression; lactation.

Route & Dosage

Hypertension
Adult: PO 5–10 mg q.d. (max: 20 mg/d in 1–2 divided doses)

Renal Impairment
Clcr <10mL/min: administer 50% of dose

Administration

Oral
  • Check pulse before administering betaxolol, oral or ophthalmic. If there are extremes (rate or rhythm), withhold medication and call the physician.
  • Be aware tablet may be crushed before administration and taken with fluid of patient's choice.

Adverse Effects (≥1%)

CV: Bradycardia, hypotension. CNS: Depression. Respiratory: Increased airway resistance. Special Senses: With ophthalmic solution, mild ocular stinging and discomfort, tearing.

Interactions

Drug: Reserpine and other catecholamine-depleting agents may cause additive hypotensive effects or bradycardia. Verapamil may cause additive heart block.

Pharmacokinetics

Absorption: 90% of PO dose reaches systemic circulation. Onset: 0.5–1 h. Peak: 2 h. Duration: >12 h. Metabolism: In liver by CYP1A2 and 2D6. Elimination: 30–40% in urine, 50–60% in bile and feces. Half-Life: 3–4 h.

Nursing Implications

Assessment & Drug Effects

  • Monitor pulse rate and BP at regular intervals in patients with severe heart disease.
  • Monitor therapeutic effectiveness. Some patients develop tolerance during long-term therapy.

Patient & Family Education

  • Report unusual pulse rate or significant changes to physician according to parameters provided.
  • Adhere to regimen EXACTLY as prescribed. Do not stop drug abruptly; angina may be exacerbated; dosage is reduced over a period of 1–2 wk.
  • Report difficulty in breathing promptly to physician. Drug withdrawal may be indicated.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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