Name: Atenolol (Tenormin)
Class: Cardioselective b1-Blocking Agent
Mechanism: Selective blockade of b1 (heart, kidney) w/rel. sparing of b2. No a effect.
Absorption: Oral (>50%). Bioavailability ~40%. Plasma levels vary 4x btwn. patients.
Dist.: <5%>
Metabolism.: Excretion, t½: Renal (mostly unchanged). Long t½ (6-9 hr.)
Toxicity/S.E.s: CV—hypotension, bradycardia, c/i for CHF or AV block. Resp—c/i in asthmatics, COPD, bronchitis, allergic rhinitis. Metabolism—caution w/diabetics (masks signs of hypoglycemia: tachycardia). CNS—weakness, fatigue, nightmares, depression. GI—n/v (uncommon). Hypersens—rash, hematologic disorders (rare).
Utility: Hypertension (¯ CO ® ¯ BP; blocks renin release). Angina pectoris (prophylactic ® exercise tolerance due to ¯ O2 demand). Cardiac arrhythmias (esp. supravent. tachyarrhyths). Acute MI (prophylaxis and reduction of infarct size and failure). Pheochromocytoma (in comb. w/alpha blocker). Essential tremor. Migraine headache (prophylaxis). Performance anxiety.
Special Features: Abrupt w/drawal may trigger MI. Cardioselectivity not great.