Atenolol information from DrugsUpdate
P - Contraindicated in pregnancy
L - Cautioned while taken during lactation
LI - Lab*
Atenolol is a selective β1 receptor antagonist, a drug belonging to the group of β-blockers, a class of drugs used primarily in Cardiovascular diseases. Introduced in 1976, atenolol was developed as a replacement for propranolol in the treatment of hypertension. The chemical works by slowing down the heart and reducing its workload. Unlike propranolol, atenolol does not pass through the blood-brain barrier thus avoiding various CNS side effects.
Whilst atenolol, the most widely used β-blocker in the United Kingdom, was once first-line treatment for hypertension, the role for β-blockers in hypertension was downgraded in June 2006 in the United Kingdom to fourth-line as they perform less well than other drugs, particularly in the elderly, and there is increasing evidence that the most frequently used β-blockers at usual doses carry an unacceptable risk of provoking type 2 diabetes.
Pharmacodynamics
Pharmacokinetics
tcmax = 2 to 4 hours after oral dosing (time elapsed before maximal concentration in the blood plasma is reached)
The mean elimination halflife is 6 hours. However, the action of the usual oral dose of 25 to 100 mg lasts over a period of 24 hours.
Atenolol is a hydrophilic drug. The concentration found in brain tissue is approximately 15% of the plasma concentration only. The drug crosses the placenta barrier freely. In the milk of breastfeeding mothers, approximately 3 times the plasma concentrations are measured.
Atenolol is almost exclusively eliminated renally and is well removable by dialysis. A compromised liver function does not lead to higher peak-activity and/or a longer halflife with possible accumulation.
Atenolol is a competitive cardioselective β1-blocker. It does not have effect on β2-receptors except in high doses. Its cardioselectivity is dose-related. Atenolol reduces resting and exercise-induced heart rate as well as myocardial contractility. Peripheral β-blockade may result in vasoconstriction. Atenolol reduces BP and heart rate which results in reduced myocardial work and O2 requirement leading to improved exercise tolerance and reduced frequency and intensity of anginal attack.
Absorption: Incompletely absorbed from the GI tract (oral); peak plasma concentrations after 1-4 hr.
Distribution: Low lipid solubility, blood-brain barrier (small amounts); crosses the placenta and enters breast milk (concentrations higher than those in plasma). Protein-binding: Minimal.
Metabolism: Hepatic: Minimal.
Excretion: Via urine; elimination half-life: 6-7 hr.
Atenolol Indications / Atenolol Uses
In angina pectoris, as prophylaxis of migraine and in hypertension
Atenolol Adverse Reactions / Atenolol Side Effects
Bronchospasm; cold extremities, fatigue, dizziness, insomnia, lethargy, confusion, headache, depression, nightmares, nausea, diarrhoea, constipation, impotence and paraesthesia.
Potentially Fatal: Heart failure, 2nd or 3rd degree AV block.
Precautions
Overdosage: Symptoms include lethargy, sinus pause, bradycardia, hypotension, bronchospasm and/or hypoglycaemia. Unabsorbed drug may be removed by induced emesis, gastric lavage or admin of activated charcoal.
Special Precautions
Compensated heart failure. Variant angina, acute MI, DM; peripheral vascular disorders; hepatic and renal dysfunction; elderly patients, children. Lactation. If atenolol and clonidine are co-admin, then gradual withdrawal of clonidine should take place a few days after withdrawal of atenolol.
Other Drug Interactions
Decreased effect with aluminum and calcium salts, barbiturates, cholestyramine, NSAIDs, ampicillin, rifampicin.
Potentially Fatal: May increase effects of drugs which slow AV conduction (digoxin, verapamil, diltiazem).
Other Interactions
Information Not Available
Dosage
Oral
Hypertension
Adult: 25-100 mg daily as a single dose, depending on response. Takes 1-2 wk for full effect to be observed.
Oral
Angina pectoris
Adult: 50-100 mg daily given as single or divided doses. Max dose: 200 mg daily.
Oral
Migraine prophylaxis
Adult: 50-100 mg daily.
Intravenous
Emergency treatment of cardiac arrhythmias
Adult: 2.5 mg injected at a rate of 1 mg/minute, may repeat every 5 minutes if needed. Max: 10 mg. Alternatively, 150 mcg/kg to be infused over 20 minutes. May repeat Inj or infusion procedure every 12 hr as needed. Once control is achieved, maintain with oral doses of 50-100 mg/day.
Intravenous
Acute myocardial infarction
Adult: To be given within 12 hr of the onset of chest pain. Inject 5-10 mg slowly at a rate of 1 mg/minute, followed by an oral dose of 50 mg 15 minutes later (if no adverse effects result from the inj). Alternatively, repeat an IV dose of 5 mg 10 minutes after the initial doser followed by an oral dose of 50 mg 10 minutes after the last IV dose. A further oral dose of 50 mg may be given 12 hr later. Thereafter, maintain with 50 mg every 12 hr or 100 mg/day for 6-9 days post-MI.
Food(before/after)
May be taken with or without food
List of Contraindications
Atenolol and Pregnancy
Contraindicated in pregnancy
Category D: There is positive evidence of human foetal risk, but the benefits from use in pregnant women may be acceptable despite the risk (e.g., if the drug is needed in a life-threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective).
Atenolol and Lactation
Caution when used during lactation
Atenolol and Children
Information Not Available
Atenolol and Geriatic
Information Not Available
Atenolol and Other Contraindications
Hypersensitivity. Sinus bradycardia, sinus node dysfunction, heart block >1st degree, compensated cardiac failure, cardiogenic shock, bronchospastic diseases, peripheral vascular diseases. Pregnancy.
Storage
Intravenous: Store at 20-25°C. Oral: Store at 20-25°C
Lab interference
Intravenous: Store at 20-25°C. Oral: Store at 20-25°C
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