Atenolol: Uses, Dosage, Side Effects and Interactions

Atenolol is a widely prescribed medication, known for its effectiveness and selectivity as a beta-blocker. With decades of clinical use, it has become a staple in managing a variety of cardiovascular conditions and, more recently, other indications. If you or someone you know is considering atenolol, understanding its uses, optimal dosing, side effects, and potential interactions is key to safe and effective therapy. This article provides an in-depth, evidence-based review, helping you make informed decisions about this well-known medication.

Uses of Atenolol

Atenolol's therapeutic scope has grown significantly since its introduction, offering benefits across several medical conditions. Understanding its uses helps patients and caregivers appreciate both its strengths and its limitations.

Condition	Description	Common Population	Key Source(s)
Hypertension	Lowers blood pressure, especially mild to moderate cases	Adults, elderly, pregnancy-associated hypertension	1234
Angina Pectoris	Reduces frequency and severity of chest pain	Adults with stable angina	38
Arrhythmias	Controls heart rhythm abnormalities (supraventricular)	Adults post-IV stabilization	3
Myocardial Infarction	Reduces mortality and recurrence post-heart attack	Adults with recent MI	38
Infantile Hemangioma	Promotes regression of vascular tumors in infants	Infants and young children	911
Glaucoma (experimental)	Reduces intraocular pressure	Patients with glaucoma	5

Table 1: Main Clinical Uses of Atenolol

Hypertension

Atenolol is perhaps best known as an antihypertensive agent. It is effective in reducing blood pressure in patients with mild to moderate hypertension, including elderly individuals and pregnant women with hypertension. However, controversies exist about its long-term cardiovascular benefits compared to other antihypertensive medications, with some studies suggesting slightly higher mortality and stroke rates when compared to other drug classes 1234. Nevertheless, atenolol remains a well-tolerated option for many patients.

Angina Pectoris

Atenolol is a first-line choice for stable angina, decreasing the frequency of anginal attacks and the need for nitroglycerin. It improves exercise tolerance and reduces the heart's workload, providing significant symptomatic relief for patients with chronic chest pain 38.

Cardiac Arrhythmias

For certain arrhythmias, especially supraventricular types, atenolol is used to maintain normal rhythm after initial control is achieved, often starting with intravenous administration followed by oral therapy 3.

Myocardial Infarction

Early intervention with intravenous atenolol, followed by oral maintenance, can reduce the risk of recurrent heart attacks and cardiovascular mortality in patients who have experienced a myocardial infarction 38.

Infantile Hemangioma

Atenolol has shown promise as an alternative to propranolol for treating infantile hemangiomas (IH)—benign vascular tumors commonly seen in infants. Studies indicate similar efficacy to propranolol but with a reduced risk of severe side effects, making it an attractive option for this indication 911.

Glaucoma (Experimental Use)

Initial studies suggest atenolol may lower intraocular pressure and could play a role in glaucoma management, though routine clinical use in this setting is not yet established 5.

Dosage of Atenolol

Getting the dose right is crucial for maximizing benefits and minimizing risks. Dosing regimens may vary depending on the indication, patient characteristics, and the presence of other medical conditions.

Indication	Typical Dose Range	Frequency	Key Source(s)
Hypertension	25–200 mg/day	Once daily	2348
Angina Pectoris	50–200 mg/day	Once daily	38
Arrhythmias	50–100 mg/day	Once daily	3
Myocardial Infarction	IV: 5–10 mg; Oral: 50–100 mg/day	IV initially, then once daily oral	38
Infantile Hemangioma	1 mg/kg/day	Once daily	11

Table 2: Typical Atenolol Dosages by Indication

Adult Dosing

• Hypertension & Angina: The common starting dose is 25–50 mg once daily, which may be increased to 100–200 mg/day if necessary. Most patients achieve optimal blood pressure and angina control with doses in this range 2348.
• Arrhythmias: Doses of 50–100 mg once daily are generally effective 3.
• Myocardial Infarction: Acute management may begin with intravenous dosing, followed by maintenance oral doses of 50–100 mg once daily 38.

Pediatric Dosing (Infantile Hemangioma)

• IH Treatment: Atenolol is typically started at 1 mg/kg once daily, with careful titration and monitoring. Studies show this dose is both effective and well-tolerated over 24 weeks of therapy in infants 11.

Pharmacokinetics and Administration

• Absorption: Oral bioavailability averages around 50–60%, with peak plasma concentrations reached in about 3 hours 678.
• Half-life: The elimination half-life is about 6–10 hours, supporting once-daily dosing for most patients 678.
• Excretion: Atenolol is primarily excreted unchanged in the urine, making dose adjustments necessary in patients with significant kidney impairment 6714.

Special Considerations

• Elderly and Renal Impairment: Dosage reduction may be required due to decreased renal clearance 6714.
• Combination Therapy: Atenolol is sometimes combined with diuretics (e.g., bendrofluazide) for enhanced antihypertensive effect 4.

Side Effects of Atenolol

Like all medications, atenolol carries the risk of side effects. However, it is generally well tolerated, and its side effect profile differs from other beta-blockers, particularly regarding central nervous system (CNS) effects.

Side Effect	Frequency/Severity	Distinctive Feature	Key Source(s)
Fatigue	Common, usually mild	Dose-dependent	23412
Bradycardia	Common	More pronounced with higher doses	3412
Cold Extremities	Common	Peripheral vasoconstriction	3
Sleep Disturbances	Rare (lowest among beta-blockers)	Due to low CNS penetration	1012
Gastrointestinal	Mild (nausea, diarrhea)	Usually transient	911
Agitation	Mild, especially in children	Reported in IH treatment	11
Severe Adverse Events	Rare (severe bradycardia, hypotension)	Less frequent than with propranolol	911

Table 3: Notable Side Effects of Atenolol

Common Side Effects

Atenolol’s most frequently reported side effects include:

• Fatigue and Tiredness: Often mild and generally improves with time or dose adjustment 23412.
• Bradycardia (Slow Heart Rate): Especially at higher doses or in individuals sensitive to beta-blockade 3412.
• Cold Hands and Feet: Resulting from reduced peripheral circulation 3.

Central Nervous System Effects

Atenolol is hydrophilic and has limited ability to cross the blood-brain barrier. As a result, sleep disturbances, nightmares, and other CNS side effects are less common compared to more lipophilic beta-blockers such as propranolol or pindolol 1012.

Gastrointestinal and Other Effects

Mild gastrointestinal symptoms like diarrhea and nausea can occur, particularly in children treated for infantile hemangioma. Agitation and sleep disturbances are occasionally reported in this group, but severe adverse events are rare 911.

Severe or Rare Adverse Effects

Life-threatening events such as profound hypotension, severe bradycardia, or bronchospasm are very rare, especially when compared to non-selective beta-blockers. In studies comparing atenolol to propranolol for IH, severe side effects were significantly less frequent with atenolol 911.

Tolerability Compared to Other Beta-blockers

• Atenolol generally causes fewer CNS side effects than propranolol and metoprolol 1012.
• Sleep disturbances are most often reported with pindolol, least with atenolol 12.

Interactions of Atenolol

Knowing how atenolol interacts with other drugs and substances is essential for avoiding reduced effectiveness or unexpected side effects.

Interacting Agent	Effect on Atenolol	Clinical Relevance	Key Source(s)
Furosemide	No significant interaction	Safe to use together	15
Aluminum Salts	↓ Atenolol absorption (~20%)	May reduce efficacy	15
Calcium Salts	↓ Atenolol absorption (up to 51%)	Significant reduction in effectiveness	15
Ampicillin	Markedly ↓ bioavailability (to 24–36%)	Avoid concurrent use if possible	16
Aspirin, Allopurinol	No significant effect	Safe to use together	16
Renal Excretion Inhibitors	May increase atenolol levels	Use caution in renal impairment	6714

Table 4: Key Atenolol Drug Interactions

Diuretics and Antihypertensives

Atenolol is often combined safely with diuretics (e.g., bendrofluazide) to achieve better blood pressure control. No clinically significant interactions have been observed with furosemide 415.

Antacids and Mineral Supplements

• Aluminum Hydroxide & Calcium Salts: These can reduce atenolol’s absorption and peak plasma levels, potentially diminishing its effectiveness. Calcium salts may lower atenolol absorption by up to 51% 15.
• Clinical Tip: If co-administration is necessary, consider spacing doses several hours apart to minimize interaction.

Antibiotics

• Ampicillin: Markedly reduces atenolol’s bioavailability, both acutely (to about 36%) and with chronic use (down to 24%). This interaction can significantly lower atenolol’s effectiveness and is best avoided 16.

Other Common Medications

• Aspirin and Allopurinol: Do not significantly affect atenolol’s kinetics or effectiveness, and are generally safe to use together 16.

Renal Drug Interactions

Atenolol is cleared via glomerular filtration and active renal secretion, involving organic cation transporters (OCT2, MATE1, MATE2-K). Drugs that impair renal function or compete for these transporters can increase atenolol levels, necessitating caution in patients with kidney disease 6714.

Pharmacological Considerations

• Drug Formulations: Drug-excipient interactions (e.g., with polyvinylpyrrolidone) can alter atenolol’s properties, but such changes are mainly relevant during drug formulation and manufacturing 13.
• Combination with Other Beta-blockers: Not recommended, as it increases the risk of bradycardia and other adverse effects.

Conclusion

Atenolol is a time-tested beta-blocker with broad applications in cardiovascular medicine and beyond. It offers reliable blood pressure and heart rate control, with a favorable side effect and interaction profile compared to many other beta-blockers.

Key Takeaways:

• Versatile Uses: Effective in hypertension, angina, arrhythmias, myocardial infarction, and infantile hemangioma 12348911.
• Once-daily Dosing: Most indications are managed with 25–200 mg once daily, or 1 mg/kg/day in infants 234811.
• Well Tolerated: Fewer CNS side effects than other beta-blockers; most adverse events are mild and transient 101112.
• Notable Interactions: Ampicillin and certain mineral supplements can significantly reduce absorption; renal excretion is clinically important 67141516.
• Special Populations: Dose adjustments may be required in the elderly and those with renal impairment 6714.

With proper use and monitoring, atenolol remains an important and effective option for many patients. Always consult your healthcare provider for personalized advice before starting or changing any medication regimen.