BETAXOLOL HYDROCHLORIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BETAXOLOL HYDROCHLORIDE (BETAXOLOL HYDROCHLORIDE).
Selective beta-1 adrenergic receptor antagonist; reduces heart rate, myocardial contractility, and blood pressure.
| Metabolism | Hepatic metabolism via CYP2D6; forms active metabolite (4-hydroxybetaxolol). |
| Excretion | Renal: 80% (as unchanged drug and inactive metabolites), Fecal: 20% |
| Half-life | Terminal elimination half-life: 14–22 hours (mean 16 hours); sufficient for once-daily dosing in hypertension; prolonged in renal impairment. |
| Protein binding | 50% bound primarily to albumin. |
| Volume of Distribution | 5–13 L/kg (large Vd indicates extensive tissue distribution, penetrating into CNS and aqueous humor). |
| Bioavailability | Oral: 89% (high first-pass metabolism, but bioavailability remains high due to low hepatic extraction). |
| Onset of Action | Oral: 1–2 hours (beta-blockade); Ophthalmic: ~30 minutes (reduction in intraocular pressure). |
| Duration of Action | Oral: 24 hours (beta-blockade persists for 24 hours, supports once-daily dosing); Ophthalmic: 12 hours (IOP reduction lasts 12–24 hours). |
10-20 mg orally once daily; maximum 20 mg/day.
| Dosage form | TABLET |
| Renal impairment | CrCl < 10 mL/min: contraindicated. CrCl 10-30 mL/min: 5 mg once daily; increase cautiously. |
| Liver impairment | Child-Pugh B or C: 5 mg once daily; monitor closely. |
| Pediatric use | Not established; use not recommended. |
| Geriatric use | Initial 5 mg once daily; titrate slowly due to increased sensitivity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BETAXOLOL HYDROCHLORIDE (BETAXOLOL HYDROCHLORIDE).
| Breastfeeding | Present in human milk in low concentrations (M/P ratio ~0.5). No reported adverse effects in breastfed infants. Caution in preterm or infants with impaired hepatic function. |
| Teratogenic Risk | First trimester: Limited human data; animal studies show increased fetal resorption at high doses. Second and third trimesters: Beta-blockers may cause fetal bradycardia, growth restriction, and hypoglycemia. Use only if benefit outweighs risk. |
| Fetal Monitoring |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Sinus bradycardia; heart block greater than first degree; cardiogenic shock; overt cardiac failure; hypersensitivity.
| Precautions | Beta-blocker withdrawal; bronchospasm in asthma; bradycardia; heart failure; peripheral vascular disease; diabetes; thyrotoxicosis; renal impairment; anaphylaxis. |
| Food/Dietary | No significant food interactions for betaxolol ophthalmic or oral formulations. Alcohol may enhance hypotensive effects; advise moderation. |
| Clinical Pearls |
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| Monitor maternal heart rate, blood pressure, and signs of bronchospasm. Fetal: heart rate and growth (ultrasound) throughout pregnancy. Neonatal: observe for bradycardia, hypoglycemia, and respiratory depression for 48 hours postpartum. |
| Fertility Effects | No significant effects on fertility reported in animal studies; limited human data. Beta-blockers may rarely cause impotence in males, but impact on conception is minimal. |
| Betaxolol is a cardioselective beta-1 blocker with low intrinsic sympathomimetic activity. In glaucoma, it reduces intraocular pressure by decreasing aqueous humor production. Systemic absorption from ophthalmic use can cause bradycardia and bronchospasm in susceptible patients. Use cautiously in patients with COPD or asthma; non-selective beta blockers are more risky, but betaxolol can still precipitate bronchospasm. Monitor heart rate in patients with pre-existing cardiac conditions. Onset for ocular effect is about 30 minutes, peak at 2 hours. Do not discontinue abruptly in patients with coronary artery disease; taper gradually. May mask signs of hypoglycemia (tachycardia) in diabetics. For hypertension, usual oral dose is 10-20 mg once daily; ophthalmic dose is 1 drop twice daily. |
| Patient Advice | Apply pressure to the tear duct (nasolacrimal occlusion) for 1-2 minutes after instilling eye drops to reduce systemic absorption. · Do not touch the dropper tip to any surface to prevent contamination. · May cause temporary blurred vision; avoid driving or operating machinery until vision clears. · Inform your doctor if you have asthma, COPD, diabetes, or thyroid disease before using this medication. · Do not stop taking this medication suddenly without consulting your doctor, especially if you have heart disease. · If you wear contact lenses, remove them before instilling eye drops and wait at least 15 minutes before reinserting. · Report slow heart rate, difficulty breathing, or swelling of the extremities immediately. · Use caution when exercising in hot weather; betaxolol can mask signs of heatstroke. |