|Trade names||Tenormin, others|
|By mouth, IV|
|Drug class||Selective β1 receptor antagonist|
|Elimination half-life||6–7 hours|
|CompTox Dashboard (EPA)|
|Chemical and physical data|
|Molar mass||266.336 g/mol g·mol−1|
|3D model (JSmol)|
Atenolol is a beta blocker medication primarily used to treat high blood pressure and heart-associated chest pain. Atenolol, however, appears not to improve mortality in those with high blood pressure. Other uses include the prevention of migraines and treatment of certain irregular heart beats. It is taken by mouth or by injection into a vein. It can also be used with other blood pressure medications.
Common side effects include feeling tired, heart failure, dizziness, depression, and shortness of breath. Other serious side effects include bronchospasm. Use is not recommended during pregnancy. Other medications are preferred when breastfeeding a young baby. It works by blocking β1-adrenergic receptors in the heart, thus decreasing the heart rate and workload.
Atenolol was patented in 1969 and approved for medical use in 1975. It is available as a generic medication. In the United States, the wholesale cost per month is less than US$15 as of 2018. In the United Kingdom, a month of treatment costs the NHS less than 5 pounds. In 2016, it was the 20th most prescribed medication in the United States, with more than 26 million prescriptions.
Atenolol is used for a number of conditions including hypertension, angina, long QT syndrome, acute myocardial infarction, supraventricular tachycardia, ventricular tachycardia, and the symptoms of alcohol withdrawal.
Atenolol is one of the most widely used β-blockers in the United Kingdom and was once the first-line treatment for hypertension. The role for β-blockers in general in hypertension was downgraded in June 2006 in the United Kingdom, and later in the United States, as they are less appropriate than calcium channel blockers, thiazide diuretics, angiotension converting enzyme (ACE) inhibitors, and angiotensin receptor blockers, particularly in the elderly.
Atenolol was the main β-blocker identified as carrying a higher risk of provoking type 2 diabetes, leading to its downgrading in the United Kingdom in June 2006 to fourth-line agent in the management of hypertension.
Antihypertensive therapy with atenolol provides weaker protective action against cardiovascular complications (e.g. myocardial infarction and stroke) compared to other antihypertensive drugs. In some cases, diuretics are superior.
Symptoms of overdose are due to excessive pharmacodynamic actions on β1 and also β2-receptors. These include bradycardia (slow heartbeat), severe hypotension with shock, acute heart failure, hypoglycemia and bronchospastic reactions. Treatment is largely symptomatic. Hospitalization and intensive monitoring is indicated. Activated charcoal is useful to absorb the drug. Atropine will counteract bradycardia, glucagon helps with hypoglycemia, dobutamine can be given against hypotension and the inhalation of a β2-mimetic as hexoprenalin or salbutamol will terminate bronchospasms. Blood or plasma atenolol concentrations may be measured to confirm a diagnosis of poisoning in hospitalized patients or to assist in a medicolegal death investigation. Plasma levels are usually less than 3 mg/L during therapeutic administration, but can range from 3–30 mg/L in overdose victims.
Atenolol has been given as an example of how slow healthcare providers are to change their prescribing practices in the face of medical evidence that indicates that a drug is ineffective. In 2012, 33.8 million prescriptions were written to American patients for this drug. In 2014, it was in the top (most common) 1% of drugs prescribed to Medicare patients. Although the number of prescriptions has been declining steadily since the evidence against its efficacy was published, it has been estimated that it would take 20 years for doctors to stop prescribing it for hypertension.