Acebutolol

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  • Class of drug: β-Adrenergic receptor blocker.
  • Mechanism of action: Competitive blocker of β adrenergic receptors in heart and blood vessels.
  • Indications/dosage/route: Oral only.
  1. Hypertension
    Adults: Initial: 400 mg/d. Maintenance: 200–1200 mg/d.
  2. Premature ventricular contractions
    Adults: Initial: 200 mg b.i.d. Maintenance: 600–1200 mg/d.

  • Adjustment of dosage
    • Kidney disease: Creatinine clearance 25–50 mL/min: decrease
    dose by 50%; creatinine clearance <25 mL/min: decrease dose
    by 75%.
    • Liver disease: None.
    • Elderly: Avoid doses >800 mg/d.
    • Pediatric: Safety and efficacy have not been established in children.

  • Contraindications:
  1. Cardiogenic shock,
  2. CHF unless it is secondary to tachyarrhythmia treated with a β blocker,
  3. sinus bradycardia and AV block greater than first degree,
  4. severe COPD.

  • Warnings/precautions
  1. Use with caution in patients with the following conditions: diabetes, kidney disease, liver disease, COPD, peripheral vascular disease.
  2. Do not stop drug abruptly as this may precipitate arrhythmias, angina, MI or cause rebound hypertension. If necessary to discontinue, taper as follows: reduce dose and reassess after 1–2 weeks; if status is unchanged, reduce by another 50% and reassess after 1–2 weeks.
  3. Drug may mask the symptoms of hyperthyroidism, mainly tachycardia.
  4. Drug may exacerbate symptoms of arterial insufficiency in patients with peripheral or mesenteric vascular disease.
  • Advice to patient
  1. Avoid driving and other activities requiring mental alertness or that are potentially dangerous until response to drug is known.
  2. Dress warmly in winter and avoid prolonged exposure to cold as drug may cause increased sensitivity to cold.
  3. Avoid drinks that contain xanthines (caffeine, theophylline, theobromine) including colas, tea, and chocolate because they may counteract the effect of the drug.
  4. Restrict dietary sodium to avoid volume expansion.
  5. Drug may blunt response to usual rise in blood pressure and chest pain under stressful conditions such as vigorous exercise and fever.
  • Adverse reactions
  1. Common: fatigue.
  2. Serious: symptomatic bradycardia, CHF, worsened AV block, hypotension, depression, bone marrow depression, SLE-like condition, bronchospasm, Peyronie’s disease, hepatitis.
  • Clinically important drug interactions
  1. Drugs that increase effects/toxicity of beta blockers: reserpine, bretylium, calcium channel blockers.
  2. Drugs that decrease effects/toxicity of beta blockers: aluminum salts, calcium salts, cholestyramine, barbiturates, NSAIDs, rifampin.

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