Tenormin

Tenormin (atenolol) is a cardioselective beta-blocker prescribed for the management of hypertension (high blood pressure) and angina pectoris (chest pain). As a cornerstone of cardiovascular therapy, it works by blocking the action of certain natural chemicals in the body, such as epinephrine, on the heart and blood vessels. This action results in a decreased heart rate, reduced blood pressure, and diminished cardiac workload, thereby improving oxygen supply and demand balance. Its well-established efficacy and favorable pharmacokinetic profile have made it a first-line treatment option in appropriate patient populations for decades under strict medical supervision.

Features

• Active Ingredient: Atenolol
• Pharmacological Class: Cardioselective beta-1 adrenergic receptor blocker
• Standard Available Strengths: 25 mg, 50 mg, and 100 mg film-coated tablets
• Administration Route: Oral
• Onset of Action: Notable hemodynamic effects typically observed within 1 hour
• Peak Plasma Concentration: Achieved within 2-4 hours post-administration
• Elimination Half-Life: Approximately 6-7 hours
• Primary Excretion: Renal (requires dosage adjustment in renal impairment)

Benefits

• Provides consistent and reliable 24-hour blood pressure control with once-daily dosing, supporting adherence to treatment regimens.
• Effectively reduces the frequency and severity of angina attacks, improving exercise tolerance and quality of life.
• Lowers myocardial oxygen demand, offering cardioprotective effects for at-risk patients.
• Exhibits relative cardioselectivity at lower therapeutic doses, minimizing the risk of bronchospasm compared to non-selective beta-blockers.
• Has a well-documented long-term safety and efficacy profile based on extensive clinical use and research.

Common use

Tenormin is primarily indicated for the management of essential hypertension, either as monotherapy or in combination with other antihypertensive agents such as thiazide diuretics. It is also indicated for the long-term management of chronic stable angina pectoris. In some clinical contexts, it may be used as part of a management strategy following a myocardial infarction (heart attack) to improve survival and prevent reinfarction, though this is not a universal first-line indication and is subject to specific clinical guidelines. Its use is always predicated on a thorough cardiovascular assessment.

Dosage and direction

Dosage is highly individualized and must be determined by a physician based on the patient’s clinical condition, renal function, and treatment response.

• Hypertension: The usual initial dose is 50 mg administered orally once daily. This may be increased to 100 mg once daily after 1-2 weeks if an adequate response is not achieved. A dose of 25 mg once daily may be considered for initial therapy in some patients (e.g., those with renal impairment).
• Angina Pectoris: The usual initial dose is 50 mg orally once daily. This may be increased to 100 mg once daily after one week if an optimal therapeutic response has not been achieved. Some patients may be maintained on 50 mg daily.
• Administration: The tablet should be swallowed whole with a glass of water. It can be taken with or without food, though consistency in timing is recommended. It is typically taken in the morning.

Dosage adjustment is necessary for patients with renal impairment. The dosing interval may be extended (e.g., 50 mg every 48 hours) based on creatinine clearance. Abrupt discontinuation of Tenormin should be avoided, as it may exacerbate angina or precipitate myocardial infarction. Therapy should be withdrawn gradually over a period of 1-2 weeks under medical supervision.

Precautions

Patients should be closely monitored, especially at the beginning of treatment and during dosage adjustments.

• Cardiac Monitoring: May mask the tachycardic symptoms of hypoglycemia and hyperthyroidism. Can precipitate or exacerbate congestive heart failure; use with caution in patients with compensated heart failure.
• Pulmonary Disease: Although cardioselective, caution is advised in patients with bronchospastic disease (e.g., asthma, COPD). Doses above 100 mg daily may lose selectivity.
• Peripheral Vascular Disease: Can precipitate or aggravate symptoms of arterial insufficiency (e.g., Raynaud’s phenomenon, intermittent claudication).
• Major Surgery: The necessity of beta-blocker therapy continuation perioperatively should be evaluated. Tenormin impairs the ability of the heart to respond to reflex stimuli.
• Diabetes Mellitus: Can potentiate insulin-induced hypoglycemia and mask signs like tachycardia. Blood glucose monitoring should be intensified.
• Psoriasis: May be aggravated by beta-blocker therapy.
• Pheochromocytoma: Should not be used unless alpha-blockade has been initiated first.

Contraindications

Tenormin is contraindicated in patients with:

• Sinus bradycardia (heart rate less than 45-50 beats per minute)
• Second- or third-degree heart block (in the absence of a functioning permanent pacemaker)
• Overt cardiac failure (unless the failure is secondary to a tachyarrhythmia treatable with beta-blockers)
• Cardiogenic shock
• Hypersensitivity to atenolol or any component of the formulation

Possible side effect

As with all medications, Tenormin can cause side effects, although not everybody gets them. Most are dose-dependent.

• Very Common/Common (>1/10 to >1/100): Bradycardia (slow heart rate), cold extremities, fatigue, dizziness, depression, shortness of breath (dyspnea) on exertion.
• Uncommon (>1/1,000 to <1/100): Sleep disturbances, nightmares, impotence/erectile dysfunction, gastrointestinal disturbances (nausea, diarrhea, constipation).
• Rare (>1/10,000 to <1/1,000): Heart block, worsening of heart failure, bronchospasm, rash, alopecia, dry eyes, visual disturbances.
• Very Rare (<1/10,000): Hallucinations, Peyronie’s disease, thrombocytopenia.

Patients should report any persistent or severe side effects to their physician.

Drug interaction

Concomitant use of Tenormin with other drugs requires careful consideration due to potential pharmacodynamic and pharmacokinetic interactions.

• Other Antihypertensives: Concomitant use with other blood pressure-lowering agents (e.g., calcium channel blockers like verapamil or diltiazem, alpha-blockers, other beta-blockers) may lead to additive hypotensive and bradycardic effects.
• Antiarrhythmics: Drugs like disopyramide, amiodarone, and propafenone can have additive negative inotropic and chronotropic effects.
• Insulin and Oral Hypoglycemics: May enhance the hypoglycemic effect and mask tachycardia, a key symptom of hypoglycemia.
• NSAIDs: Non-steroidal anti-inflammatory drugs (e.g., ibuprofen, naproxen) may antagonize the antihypertensive effect.
• Sympathomimetics: Drugs that stimulate beta-receptors (e.g., adrenaline, isoprenaline, decongestants) may have their effects blunted.
• Clonidine: Exaggerated hypertensive crisis can occur if clonidine is withdrawn during concomitant beta-blocker therapy. Tenormin should be withdrawn several days before slowly discontinuing clonidine.
• Digoxin: Concomitant use increases the risk of bradycardia.

A comprehensive review of a patient’s medication list, including over-the-counter drugs and supplements, is essential before initiating therapy.

Missed dose

If a dose is missed, it should be taken as soon as remembered on the same day. If it is almost time for the next scheduled dose, the missed dose should be skipped. A double dose should never be taken to make up for a forgotten one. Patients should resume their regular dosing schedule and inform their physician if multiple doses are frequently missed.

Overdose

Overdose with Tenormin is characterized by severe bradycardia, hypotension, heart failure, bronchospasm, and hypoglycemia. The most common signs are a very slow heart rate and low blood pressure, which can lead to cardiovascular collapse.

• Management: This is a medical emergency requiring intensive supportive care. Treatment is symptomatic and supportive. Primary attention should be given to re-establishing adequate heart rate and blood pressure. This may include:
  • Atropine: For symptomatic bradycardia.
  • Vasopressors: Such as norepinephrine, epinephrine, or dopamine for hypotension and shock (use with extreme caution due to potential for unopposed alpha-effects).
  • Glucagon: Has positive inotropic and chronotropic effects and may be beneficial.
  • Cardiac Pacing: For refractory bradycardia or heart block.
  • Beta-2 Agonists: (e.g., salbutamol, isoprenaline) for bronchospasm.
  • Intravenous Glucose: For hypoglycemia. Gastric lavage may be considered if ingestion was very recent.

Storage

• Store in the original package or container to protect from light and moisture.
• Keep at room temperature (15°C - 30°C or 59°F - 86°F).
• Keep out of sight and reach of children.
• Do not use after the expiration date printed on the packaging.
• Do not dispose of medication via wastewater or household waste. Consult a pharmacist on the proper disposal method in accordance with local guidelines.

Disclaimer

This information is for educational and informational purposes only and does not constitute medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or medication. Never disregard professional medical advice or delay in seeking it because of something you have read here. The author and publisher are not responsible for any specific health or allergy needs that may require medical supervision or for any adverse effects resulting from the use of information contained herein.

Reviews

• Clinical Consensus (Cardiology): “Atenolol remains a foundational agent in our antihypertensive and antianginal arsenal. Its once-daily dosing and predictable pharmacokinetics support long-term adherence. While newer agents exist, its efficacy and cost-effectiveness for appropriate patients are undeniable. Monitoring renal function is paramount for safe prescribing.”
• Patient Experience (Long-term user): “I’ve been on Tenormin 50mg for my hypertension for over five years. It has consistently kept my blood pressure in the normal range with minimal side effects. I experienced some tiredness initially, but it subsided after a few weeks. I appreciate the simplicity of one pill a day.”
• Clinical Trial Data: Large-scale studies, such as the ASCOT trial, have contributed to the understanding of beta-blockers’ role in hypertension management. While debate exists regarding their position as first-line therapy compared to newer classes, they are still widely recommended in specific scenarios, particularly in patients with concomitant angina or post-myocardial infarction.