What is the half-life of Nadolol (Nadol)?

Half-Life of Nadolol

The half-life of nadolol is approximately 20 to 24 hours in patients with normal renal function. 1

Pharmacokinetic Profile of Nadolol

Nadolol is a nonselective beta-adrenergic receptor blocking agent with several key pharmacokinetic properties:

• Absorption: Variable oral absorption, averaging about 30% bioavailability
• Distribution: Approximately 30% of nadolol in serum is reversibly bound to plasma protein
• Metabolism: Unlike many other beta-blockers, nadolol is not metabolized by the liver
• Excretion: Excreted unchanged, principally by the kidneys
• Half-life: 20 to 24 hours in patients with normal renal function 1

Factors Affecting Nadolol's Half-Life

The half-life of nadolol can vary significantly based on several factors:

• Renal function: Since nadolol is primarily excreted unchanged by the kidneys, its half-life increases significantly in patients with renal failure 1
• Age: In children, the serum half-life may be shorter (3.2-4.3 hours) compared to adults 2
• Kidney disease: In patients with chronic kidney disease, the half-life can increase to 18.2-68.6 hours (up to double the normal half-life) 2

Clinical Implications of Nadolol's Half-Life

The long half-life of nadolol has several important clinical implications:

1. Once-daily dosing: The extended half-life allows for once-daily administration in both hypertension and angina pectoris 1, 3

2. Steady-state concentrations: Steady-state serum concentrations are achieved in six to nine days with once-daily dosing in individuals with normal renal function 1

3. Dose adjustments: Dosage adjustments are necessary for patients with renal impairment due to the prolonged half-life 1

4. Extracorporeal removal: During hemodialysis, the half-life of nadolol is reduced to approximately 3.56 hours (range 3.0-8.5 hours), indicating that it can be effectively removed by hemodialysis 4, 2

Comparison to Other Beta-Blockers

Nadolol's half-life of 20-24 hours is longer than many other beta-blockers, making it one of the few beta-blocking drugs that have clearly been shown to be effective with once-daily administration 3. This contrasts with other beta-blockers that may require multiple daily doses for optimal effect.

Common Pitfalls

1. Renal function assessment: Failing to assess renal function before prescribing nadolol can lead to drug accumulation and toxicity in patients with kidney impairment

2. Drug interactions: The bioavailability of nadolol can be significantly reduced by co-administration of green tea 2

3. Enterohepatic circulation: Nadolol undergoes enterohepatic circulation, and activated charcoal can decrease its bioavailability 2

4. Abrupt discontinuation: As with other beta-blockers, abrupt discontinuation of nadolol in patients with coronary artery disease can lead to exacerbation of angina, and in some cases, myocardial infarction and ventricular dysrhythmias 1

Understanding nadolol's long half-life is crucial for appropriate dosing, especially in patients with renal impairment, and helps explain its suitability for once-daily administration in clinical practice.