What is the recommended dosing regimen for atenolol (beta-blocker) in a patient with hypertension, considering factors such as renal function, age, and comorbidities like angina, post-myocardial infarction, asthma, or diabetes?

Atenolol Dosing

Hypertension

For hypertension, start atenolol at 50 mg once daily, and if blood pressure is not controlled within 1-2 weeks, increase to 100 mg once daily—doses beyond 100 mg daily are unlikely to provide additional benefit. 1

Initial Dosing

• Begin with 50 mg once daily, either as monotherapy or added to diuretic therapy 1
• The full antihypertensive effect typically appears within 1-2 weeks 1
• Once-daily dosing is therapeutically equivalent to divided doses and improves adherence 2

Dose Titration

• If blood pressure remains uncontrolled after 1-2 weeks on 50 mg daily, increase to 100 mg once daily 1
• Increasing beyond 100 mg daily is unlikely to produce further benefit 1
• Studies demonstrate that 100 mg daily achieves optimal blood pressure reduction (mean reduction of 25/16 mmHg) 3

Combination Therapy

• Atenolol may be combined with thiazide diuretics, hydralazine, prazosin, or alpha-methyldopa 1
• However, current hypertension guidelines recommend beta-blockers only as fourth-line or later agents, or when compelling indications exist (angina, post-MI, heart failure with reduced ejection fraction) 4, 5

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Angina Pectoris

For angina, start with 50 mg once daily and increase to 100 mg daily after one week if needed; some patients require 200 mg once daily for optimal 24-hour control. 1

Initial Dosing

• Start with 50 mg once daily 1
• Assess response after one week 1

Dose Optimization

• Increase to 100 mg once daily if initial response is inadequate 1
• Some patients require 200 mg once daily for optimal effect and full 24-hour control 1
• Maximum early effect on exercise tolerance occurs with 50-100 mg, but higher doses (200 mg) provide better sustained 24-hour control 1

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Post-Myocardial Infarction

For acute MI, administer 5 mg IV over 5 minutes, repeat with another 5 mg IV 10 minutes later, then transition to 50 mg orally 10 minutes after the last IV dose, followed by 50 mg orally 12 hours later, then continue with either 100 mg once daily or 50 mg twice daily for 6-9 days. 1

Acute Phase (IV Administration)

• Give 5 mg IV over 5 minutes 1
• Repeat with another 5 mg IV 10 minutes later 1
• Administer under carefully controlled conditions with continuous monitoring of blood pressure, heart rate, and ECG 1

Transition to Oral Therapy

• In patients who tolerate the full 10 mg IV dose, initiate 50 mg orally 10 minutes after the last IV dose 1
• Give another 50 mg orally 12 hours later 1
• Continue with either 100 mg once daily or 50 mg twice daily for 6-9 days or until hospital discharge 1

Alternative Oral-Only Regimen

• If IV beta-blocker is contraindicated or questionable, give 50 mg orally twice daily or 100 mg once daily for at least 7 days 1

Long-Term Continuation

• Beta-blocker therapy may be continued for 1-3 years post-MI if no contraindications exist 1

Discontinuation Precautions

• Discontinue immediately if bradycardia, hypotension requiring treatment, or other adverse effects occur 1

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Special Populations

Elderly Patients

In elderly patients, start at the low end of the dosing range (25 mg daily for hypertension) due to age-related decline in renal function. 1

• Dose selection should be cautious, reflecting decreased renal, hepatic, or cardiac function 1
• Atenolol excretion decreases with advancing age 1
• For hypertension in elderly patients, consider starting with 25 mg once daily and assess efficacy carefully, including trough blood pressure measurements 1

Renal Impairment

Atenolol dosing must be reduced in renal impairment because it is eliminated entirely unchanged by the kidneys. 1, 6

Dosing by Creatinine Clearance:

• CrCl 15-35 mL/min/1.73m²: Maximum 50 mg daily (elimination half-life 16-27 hours) 1
• **CrCl <15 mL/min/1.73m²**: Maximum 25 mg daily (elimination half-life >27 hours) 1
• No significant accumulation occurs until CrCl falls below 35 mL/min/1.73m² 1

Hemodialysis:

• Give 25-50 mg after each dialysis session under hospital supervision, as marked falls in blood pressure can occur 1

Diabetes Mellitus

Atenolol is preferable to non-selective beta-blockers in diabetic patients due to its cardioselectivity, though it may impair glucose tolerance. 6, 7

• As a beta-1 selective agent, atenolol causes less interference with insulin release and glucose metabolism compared to non-selective agents 6
• Monitor glucose control, as some impairment of glucose tolerance may occur 7

Asthma

Atenolol is preferable to non-selective beta-blockers in patients with asthma due to its cardioselectivity, but use with caution as beta-1 selectivity is dose-dependent. 6

• Beta-1 selectivity reduces but does not eliminate bronchospasm risk 6
• Monitor respiratory symptoms closely 6

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Important Clinical Considerations

Cessation of Therapy in Angina

• Withdrawal must be gradual in patients with angina pectoris 1
• Patients should be carefully observed and advised to limit physical activity during withdrawal 1
• Abrupt discontinuation can precipitate acute coronary events 1

Monitoring Parameters

• Blood pressure (measure trough levels before next dose to ensure 24-hour control) 1
• Heart rate 1
• Renal function (creatinine clearance) in all patients, especially elderly 1
• Blood glucose in diabetic patients 7
• Respiratory symptoms in patients with asthma 6

Central Nervous System Effects

• Atenolol has low lipid solubility and limited brain penetration, resulting in fewer CNS side effects compared to propranolol 6, 8

Metabolic Effects

• May increase plasma triglycerides and VLDL triglycerides, though clinical significance is uncertain 8