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Indications and Dosage
Ophthalmic
Chronic open-angle glaucoma, Ocular hypertension Adult: As 0.25% suspension or 0.5% solution: Instil 1 drop in the affected eye(s) bid. Oral Hypertension Adult: Initially, 5-10 mg once daily, may increase to 20 mg daily after 1-2 weeks if necessary.
Elderly: Initially, 5 mg daily. |
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Renal Impairment
Oral:
Severe or patients on haemodialysis: Initially, 5 mg daily, may increase by increments of 5 mg daily every 2 weeks. Max: 20 mg daily. |
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Administration
May be taken with or without food.
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Contraindications
Sick sinus syndrome; 2nd- or 3rd-degree AV block (without pacemaker); cardiogenic shock, overt cardiac failure, Prinzmetal's angina, untreated phaeochromocytoma; severe bronchial asthma and COPD.
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Special Precautions
Patient with history of atopy or severe anaphylaxis to allergens, 1st-degree AV block, compensated heart failure, cerebrovascular insufficiency, myasthenia gravis, metabolic acidosis, diabetes mellitus, bronchospastic disease, peripheral vascular disease, Raynaud's disease. May mask the signs and symptoms of hypoglycaemia and hyperthyroidism. Avoid abrupt withdrawal. Hepatic and renal impairment. Elderly. Pregnancy and lactation.
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Adverse Reactions
Significant: Anaphylactic reactions, hypoglycaemia, exacerbation of myasthenia related muscle weakness (e.g. diplopia, ptosis); severe exacerbation of angina, ventricular arrhythmias, MI, new-onset thyroid storm (following abrupt withdrawal).
Cardiac disorders: Bradycardia, arrythmia. Eye disorders: Eye discomfort and stinging, blurred vision, increased lacrimation. Gastrointestinal disorders: Nausea, dysgeusia. General disorders and administration site conditions: Asthenia, oedema. Infections and infestations: Bacterial keratitis. Investigations: Positive antinuclear antibody titre. Nervous system disorders: Headache, syncope, dizziness. Psychiatric disorders: Rarely, anxiety, insomnia, depression. Reproductive system and breast disorders: Rarely, decreased libido. Respiratory, thoracic and mediastinal disorders: Asthma, dyspnoea, pharyngitis, rhinitis. Skin and subcutaneous tissue disorders: Rash, alopecia, exacerbation of psoriasis. Vascular disorders: Hypotension, cold and cyanotic hands and feet. Potentially Fatal: Severe respiratory reactions (e.g. bronchospasm), cardiac reactions (e.g. cardiac failure). |
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Ophth/PO: C
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Patient Counseling Information
Ophthalmic: Remove contact lenses prior to administration and wait for 15 minutes before reinserting.
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Monitoring Parameters
Monitor blood pressure, heart rate, kidney function; IOP (ophthalmic). Assess for the signs and symptoms of bronchospasm (patients with bronchospastic disease), serum glucose (patients with diabetes).
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Overdosage
Symptoms: Bradycardia, hypotension, bronchospasm, acute cardiac failure. Management: Symptomatic and supportive treatment. Perform gastric lavage. Administer pressor agents (e.g. dopamine, dobutamine, norepinephrine) for hypotension. Give aminophylline to treat bronchospasm. Administer IV atropine for vagal blockade; if there is no response, isoprenaline may be administered cautiously. Provide conventional therapy (e.g. digitalis, diuretics, oxygen) for acute cardiac failure.
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Drug Interactions
Additive effect with antiarrhythmics (e.g. amiodarone, disopyramide), Ca channel blockers, β-adrenergic blockers, catecholamine-depleting drugs (e.g. reserpine), parasympathomimetics, and guanethidine. Increased risk of bradycardia with digitalis glycosides.
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Lab Interference
Oral: May interfere with glaucoma-screening test. May cause a false-positive aldosterone/renin ratio.
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Action
Description:
Mechanism of Action: Betaxolol is a cardioselective, β1-receptor blocker, with little to no effect on β2-receptors. It lacks intrinsic sympathomimetic activity and weak membrane-stabilising activity. It also reduces aqueous humour production resulting in reduction of intraocular pressure (IOP). Onset: 1-1.5 hours (oral); within 30 minutes (ophthalmic). Duration: ≥12 hours (ophthalmic). Pharmacokinetics: Absorption: Almost completely absorbed from the gastrointestinal tract. Bioavailability: Approx 90% (oral). Time to peak plasma concentration: 1.5-6 hours (oral). Distribution: Crosses the placenta and enters breast milk. Plasma protein binding: Approx 50%. Metabolism: Metabolised in the liver into multiple metabolites. Undergoes minimal first-pass metabolism. Excretion: Via urine (>80%; approx 15% as unchanged drug and inactive metabolites). Elimination half-life: 14-22 hours. |
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Chemical Structure
 Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 2369, Betaxolol. https://pubchem.ncbi.nlm.nih.gov/compound/Betaxolol. Accessed Apr. 26, 2024. |
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Storage
Store between 15-25°C.
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MIMS Class
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ATC Classification
C07AB05 - betaxolol ; Belongs to the class of selective beta-blocking agents. Used in the treatment of cardiovascular diseases.
S01ED02 - betaxolol ; Belongs to the class of beta blocking agents. Used in the treatment of glaucoma. |
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References
Anon. Betaxolol (Ophthalmic). AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 03/04/2024. Anon. Betaxolol (Systemic). AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 03/04/2024. Betac (Komedic Sdn Bhd). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 03/04/2024. Betaxolol (Ophthalmic). UpToDate Lexidrug, Lexi-Drugs Multinational Online. Waltham, MA. UpToDate, Inc. https://online.lexi.com. Accessed 03/04/2024. Betaxolol (Systemic). UpToDate Lexidrug, Lexi-Drugs Multinational Online. Waltham, MA. UpToDate, Inc. https://online.lexi.com. Accessed 03/04/2024. Betaxolol 0.5% Eye Drops (FDC International Ltd). MHRA. https://products.mhra.gov.uk. Accessed 03/04/2024. Betaxolol Hydrochloride Ophthalmic Solution, 0.5% as Base (Sandoz Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 03/04/2024. Betaxolol Hydrochloride Tablet, Coated (KVK-Tech, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 03/04/2024. Betaxolol Hydrochloride Tablet, Coated (KVK-Tech, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 03/04/2024. Buckingham R (ed). Betaxolol Hydrochloride. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 03/04/2024. Joint Formulary Committee. Betaxolol Hydrochloride. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 17/04/2024. Novartis New Zealand Limited. Betoptic Eye Drops 0.5%, 0.25% data sheet 02 June 2023. Medsafe. http://www.medsafe.govt.nz. Accessed 03/04/2024.
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