1. Clinical & Scientific Overview
Atenolol (TIP-MED-000008, Reference Code [3.8]) is classified under
Cardiovascular & Antithrombotic Medicines (Ch 03) as a Hydrophilic Cardioselective Beta-1 Adrenergic Blocker.
Within the Indian regulatory and compendial framework, it is governed under Schedule H Prescription Drug (To be sold by retail on the prescription of a Registered Medical Practitioner only — Drugs Rules 1945).
Aquazide (Sun Pharma), Hydrazide (Cipla)
Oral Tablets: 25 mg, 50 mg, 100 mg
3. Mechanism of Action & Pharmacodynamics
Hydrophilic Cardioselective Beta-1 Adrenergic Blocker acting on target receptor/enzyme pathways in Cardiovascular & Antithrombotic Medicines (Ch 03): clinical efficacy is mediated via Hydrophilic Cardioselective Beta-1 Adrenergic Blocker for Hypertension; chronic stable angina pectoris; supraventricular arrhythmias; post-MI prophylaxis..
4. Therapeutic Indications & Evidence-Supported Uses
- Hypertension
- chronic stable angina pectoris
- supraventricular arrhythmias
- post-MI prophylaxis
🇮🇳 Jurisdiction & Indication Note: Indications and schedules reflect Indian compendial and regulatory records (CDSCO / Indian Pharmacopoeia & NFI / NLEM 2022). Where international reference labels (US FDA DailyMed / NCBI StatPearls) are cited for pharmacokinetic or mechanistic parameters, international approvals do not automatically imply CDSCO approval in India.
5. Educational Dosage Context, Formulations & Administration
Educational Dosing & Regimen Summary: General Adult Reference: Hypertension: 25 mg–50 mg once daily (up to 100 mg/day in angina). Dosing strictly depends on renal function. Follow physician prescription.
Administration & Meal Timing: With or without food (food and fruit juices slightly decrease absorption; take consistently at the same time). | Once daily in the morning.
6. Pharmacokinetics, Metabolism & Renal/Hepatic Adjustment
Absorption, distribution, metabolism, and excretion follow class pharmacokinetic profile; verify patient renal/hepatic function.
Renal: Strictly renal-function dependent! Unlike metoprolol, atenolol is excreted almost entirely unchanged by the kidneys. If CrCl 15–35 mL/min: maximum dose 50 mg once daily (or 25 mg OD). If CrCl <15 mL/min: maximum 25 mg once daily or 50 mg every alternate day. Hepatic: No dose adjustment needed.
Renal: Strictly renal-function dependent! Unlike metoprolol, atenolol is excreted almost entirely unchanged by the kidneys. If CrCl 15–35 mL/min: maximum dose 50 mg once daily (or 25 mg OD). If CrCl <15 mL/min: maximum 25 mg once daily or 50 mg every alternate day. Hepatic: No dose adjustment needed.
Renal: Strictly renal-function dependent! Unlike metoprolol, atenolol is excreted almost entirely unchanged by the kidneys. If CrCl 15–35 mL/min: maximum dose 50 mg once daily (or 25 mg OD). If CrCl <15 mL/min: maximum 25 mg once daily or 50 mg every alternate day. Hepatic: No dose adjustment needed.
7. Contraindications, Precautions & High-Risk Warnings
- Contraindicated in bradycardia (<50 bpm), 2nd/3rd degree heart block, overt heart failure, cardiogenic shock, and severe asthma. Less effective than CCBs/ARBs/thiazides for primary stroke prevention in elderly hypertension unless specific cardiac indication exists.
Key Clinical Precautions: Renal: Strictly renal-function dependent! Unlike metoprolol, atenolol is excreted almost entirely unchanged by the kidneys. If CrCl 15–35 mL/min: maximum dose 50 mg once daily (or 25 mg OD). If CrCl <15 mL/min: maximum 25 mg once daily or 50 mg every alternate day. Hepatic: No dose adjustment needed.
8. Adverse Effects Profile
- Bradycardia, cold hands and feet, fatigue, lethargy, dizziness, mild glucose intolerance / dyslipidaemia.
- Severe bradycardia, heart block, bronchospasm, exacerbation of peripheral arterial disease (Raynaud's/claudication), masked hypoglycaemia.
- Monitor for severe hypersensitivity, organ toxicity, or dose-limiting adverse events.
9. Major Drug–Drug, Drug–Food & Drug–Herb Interactions
- Verapamil, diltiazem, digoxin, and amiodarone cause severe bradycardia and heart block
- Ampicillin and calcium salts may reduce oral absorption
- NSAIDs reduce antihypertensive effect
10. Clinical Monitoring, Patient Counselling & Storage
Clinical & Laboratory Monitoring: Monitor clinical response, baseline renal/hepatic parameters, and relevant serum biomarkers.
Pharmacist Patient Counselling Points:
- Patient Counselling Checklist: Take with plain water (avoid taking with fruit juices). Never stop taking atenolol suddenly even if you feel well, as stopping abruptly can trigger severe chest pain or a heart attack. Check pulse regularly.
- Meal & Clock Timing Instruction: With or without food (food and fruit juices slightly decrease absorption; take consistently at the same time). (Once daily in the morning.)
- Missed Dose Protocol: Take as soon as remembered unless within 8 hours of the next scheduled dose; never double the dose.
- Geriatric Dispensing Pearl: Because renal clearance declines with age, elderly CGHS patients on standard 50 mg–100 mg atenolol frequently accumulate the drug, presenting with profound fatigue, heart rate <45 bpm, and syncopal falls. Recommend renal dose verification (usually ≤25 mg OD) if CrCl <35 mL/min.
Storage, Stability & Dispensing Safeguards: Store below 25°C–30°C in original moisture- and light-resistant packaging out of reach of children. Available forms: Oral Tablets: 25 mg, 50 mg, 100 mg
11. Visual Pharmacology & Mechanism Diagram (svg-v339-01-adme-12-step-journey)
12. Authoritative References, Regulatory Sources & Editorial Disclaimer
Primary Compendial & Guideline Reference: Indian Pharmacist Desk Reference — Professional Edition 2.7 (2026–27) • Ch 03 [3.8] (p. 24)
Official Verification Portals: Indian Pharmacopoeia Commission (IPC) & National Formulary of India (NFI) • Central Drugs Standard Control Organization (CDSCO) • Ministry of Health & Family Welfare — NLEM 2022 • NCBI Bookshelf / StatPearls Pharmacology Reference • DailyMed (US FDA Official Prescribing Reference)
Last Medically & Pharmaceutically Reviewed: 2026-11-10 • Verification Status: HANDBOOK_SOURCE_CONTENT
Educational & Clinical Disclaimer: This reference profile is published solely for pharmacy education, academic study, and professional clinical reference. It does not substitute for patient-specific clinical judgement, qualified specialist oncology/medical supervision, or official CDSCO/IP prescribing information. Never self-medicate with prescription, Schedule H/H1/X, NDPS, or oncology medicines.
13. Related Reference Monographs, Educational Guides & Visual Concept
💊 Related Pharmacological / Category Profiles
- [3.10] Bisoprolol Fumarate — Highly Cardioselective Beta-1 Adrenergic Blocker
- [3.11] Chlorthalidone — Thiazide-Like Diuretic (Long-Acting Sulfonamide Derivative)
- [3.12] Hydrochlorothiazide (HCTZ) — Thiazide Diuretic (Distal Convoluted Tubule Na+/Cl- Cotransporter
- [3.13] Furosemide (Frusemide) — High-Ceiling Loop Diuretic (Na+-K+-2Cl- Cotransporter Inhibitor)
