Atenolol

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Atenolol
Systematic (IUPAC) name
(RS)-2-{4-[2-hydroxy-3-(propan-2-ylamino)propoxy]phenyl}acetamide
Identifiers
CAS number 29122-68-7
ATC code C07AB03
PubChem CID 2249
IUPHAR ligand 548
DrugBank APRD00172
ChemSpider 2162 YesY
UNII 50VV3VW0TI YesY
KEGG D00235 YesY
ChEMBL CHEMBL24 YesY
Chemical data
Formula C14H22N2O3 
Mol. mass 266.336 g/mol
SMILES eMolecules & PubChem
Pharmacokinetic data
Bioavailability 40-50%
Protein binding 6-16%
Metabolism Hepatic <10%
Half-life 6-7hours
Excretion Renal
Lactic (In lactiferous females)
Therapeutic considerations
Pregnancy cat. C(AU) D(US)
Legal status Prescription only
Routes Oral or IV
 YesY(what is this?)  (verify)

Atenolol (Tenormin) is a selective β1 receptor antagonist, a drug belonging to the group of beta blockers (sometimes written 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 central nervous system side effects.[1]

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 hypertension was downgraded in June 2006 in the United Kingdom to fourth-line, as they perform less appropriately or effectively than newer drugs, particularly in the elderly. Some evidence suggests that even in normal doses the most frequently used β-blockers carry an unacceptable risk of provoking type 2 diabetes.[2]

Contents

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[edit] Medical uses

Atenolol is used for a number of conditions including: hypertension, angina, acute myocardial infarction, supraventricular tachycardia, ventricular tachycardia, congestive heart failure, prevention of migraine headaches, and the symptoms of alcohol withdrawal.[3]

It is also used to treat the symptoms of Graves Disease, until antithyroid medication can take effect.

Due to its hydrophilic properties, the drug is less suitable in migraine prophylaxis compared to propranolol, because, for this indication, atenolol would have to reach the brain in high concentrations, which is not the case.[citation needed]

[edit] Combination treatment of hypertension

If atenolol alone fails to control arterial hypertension, the drug can be combined with a diuretic (e.g. with chlortalidone in co-tenidone) and/or a vasodilator (hydralazine, or in severe cases minoxidil). Central alpha-agonists (e.g. clonidine), ACE Inhibitors or Angiotensin II receptor antagonists such as losartan can also be given additionally. Exert caution with calcium-antagonists of the verapamil-type as adjunct therapy because of additional negative impact on the muscular strength of the heart. Use of calcium-antagonists of the nifedipine-type is controversial.

[edit] Contraindications

Caution: patients with preexisting bronchial asthma

Caution: only if clearly needed during pregnancy, as atenolol may retard fetal growth and possibly cause other abnormalities.

[edit] Side effects

Atenolol causes significantly fewer central nervous system side effects (depression, nightmares) and fewer bronchospastic reactions,[clarification needed] both due to its particular pharmacologic profile.[citation needed]

It 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.[2]

In addition, β-blockers blunt the usual sympathetic nervous system response to hypoglycemia (i.e. sweating, agitation, tachycardia). These drugs therefore have an ability to mask a dangerously low blood sugar, which further decreases their safety and utility in diabetic patients.

Side effects include:

These side effects may or may not be experienced, but if they are, you should notify your doctor.

More serious side effects can include:

Serious side effects may require urgent medical attention. Some of these side effects are rare and others (not mentioned in the above list) can occur in some people.

[edit] Asthma

Atenolol is classified as a β1-selective (or 'cardioselective') drug, one that exerts greater blocking activity on myocardial β1-receptors than on β2 receptors in the lung. The β2 receptors are responsible for keeping the bronchial system open. If these receptors are blocked, bronchospasm with serious lack of oxygen in the body can result. However, due to its cardioselective properties, the risk of bronchospastic reactions if using atenolol is reduced compared to nonselective drugs as propranolol. Nonetheless, this reaction may also be encountered with atenolol at high doses. Although traditionally B-blockers have been contraindicated when a person carries a diagnosis of asthma, recent studies have revealed that at moderate doses selective B blockers such as Atenolol are well tolerated.

Provisional data suggests that 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. However, controlled studies are lacking.[4]

Unlike most other commonly-used β-blockers, atenolol is excreted almost exclusively by the kidneys. This makes it attractive for use in individuals with end-stage liver disease.

[edit] Overdose

Symptoms of overdose are due to excessive pharmacodynamic actions on β1 and also β2-receptors. These include bradycardia, severe hypotension with shock, acute heart failure, hypoglycemia and bronchospastic reactions. Treatment is largely symptomatic. Hospitalization and intensive monitoring is indicated. In early cases emesis can be induced. 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.[5][6]

[edit] Pharmacokinetic data

[edit] References

  1. ^ Agon P, Goethals P, Van Haver D, Kaufman JM (August 1991). "Permeability of the blood-brain barrier for atenolol studied by positron emission tomography". J. Pharm. Pharmacol. 43 (8): 597–600. PMID 1681079. 
  2. ^ a b Sheetal Ladva (2006-06-30). "Updated NICE guideline on the management of hypertension in adults in primary care". National Institute for Health and Clinical Excellence. http://www.nelm.nhs.uk/en/NeLM-Area/Evidence/Guidelines/Updated-NICE-guideline-on-the-management-of-hypertension-in-adults-in-primary-care/. Retrieved 2009-02-03. 
  3. ^ "Atenolol". The American Society of Health-System Pharmacists. http://www.drugs.com/monograph/atenolol.html. Retrieved 3 April 2011. 
  4. ^ Carlberg B, Samuelsson O, Lindholm LH (2004). "Atenolol in hypertension: is it a wise choice?". Lancet 364 (9446): 1684–9. doi:10.1016/S0140-6736(04)17355-8. PMID 15530629. 
  5. ^ DeLima LG, Kharasch ED, Butler S. Successful pharmacologic treatment of massive atenolol overdose: sequential hemodynamics and plasma atenolol concentrations. Anesthesiology 83:204-207, 1995.
  6. ^ R. Baselt, Disposition of Toxic Drugs and Chemicals in Man, 8th edition, Biomedical Publications, Foster City, CA, 2008, pp. 116-117.

[edit] External links

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