Atenolol

Intravenous
Cardiac arrhythmias

Intravenous
Acute myocardial infarction

Oral
Hypertension

Oral
Angina pectoris

Oral
Cardiac arrhythmias

Oral
Acute myocardial infarction

Oral:
Patient on haemodialysis: 25-50 mg after each dialysis session.

CrCl (mL/min)	Dosage
<15	Max: 25 mg daily or 50 mg on alternate days.
15-35	Max: 50 mg daily.

Intravenous:

CrCl (mL/min)	Dosage
<15	Max: 10 mg once every 4 days.
15-35	Max: 10 mg once every 2 days.

May be taken with or without food.

Sinus bradycardia, cardiogenic shock, hypotension, metabolic acidosis, 2nd- or 3rd-degree heart block, severe peripheral arterial disease, sick sinus syndrome, uncontrolled cardiac failure, untreated phaeochromocytoma.

Patient with poor cardiac reserve, compensated heart failure, Prinzmetal's angina, peripheral vascular disease, Raynaud’s phenomenon, 1st-degree heart block, bronchospastic disease, history of anaphylactic reaction to allergens; diabetes mellitus, myasthenia gravis, psoriasis. Patient undergoing surgery. Avoid abrupt withdrawal. May mask the signs and symptoms of hypoglycaemia and hyperthyroidism (particularly tachycardia). Elderly. Renal impairment. Pregnancy and lactation.

Significant: Bradycardia; may exacerbate angina and precipitate MI and ventricular arrhythmias after abrupt discontinuation (in patients with angina); may precipitate or aggravate peripheral arterial insufficiency.
Ear and labyrinth disorders: Vertigo.
Gastrointestinal disorders: Nausea, diarrhoea, dry mouth.
General disorders and administration site conditions: Fatigue, lethargy.
Immune system disorders: Hypersensitivity reaction (including urticaria and angioedema).
Investigations: Elevated transaminase levels.
Musculoskeletal and connective tissue disorders: Lupus-like syndrome.
Nervous system disorders: Dizziness, drowsiness.
Psychiatric disorders: Sleep disturbances, depression.
Skin and subcutaneous tissue disorders: Rarely, exacerbation of psoriasis, psoriasiform skin reactions.
Vascular disorders: Cold extremities, hypotension, orthostatic hypotension.

IV/PO: D

Monitor blood pressure and heart rate (before and after initiation of therapy and following any dose changes); serum glucose (in diabetic patients); renal function. Obtain ECG when used for acute cardiac treatment.

Symptoms: Lethargy, wheezing, bronchospasm, sinus pause, acute cardiac insufficiency, bradycardia, hypotension, hypoglycaemia. Management: Symptomatic and supportive treatment. Closely monitor the patient. Perform gastric lavage, induce emesis, or administer activated charcoal and laxative. Treat hypotension and shock with plasma or plasma substitutes. May consider haemodialysis or haemoperfusion. In case of excessive bradycardia, administer atropine 1-2 mg IV and/or use a pacemaker. If necessary, this may be followed by glucagon 10 mg via IV bolus inj and may be repeated or followed by glucagon 1-10 mg/hour IV infusion depending on patient response. If glucagon is unavailable or no response occurred, may give a β-adrenoceptor stimulant (e.g. dobutamine) via IV infusion. Hypotension and acute cardiac insufficiency may also be treated by dobutamine. Administer bronchodilators to reverse bronchospasm. Administer IV dextrose to treat hypoglycaemia.

May increase the risk of severe hypotension, bradycardia, and heart failure with diltiazem or verapamil. Additive hypotensive effect with catecholamine-depleting agents (e.g. reserpine) and other Ca channel blockers (e.g. nifedipine). May increase the risk of bradycardia when given with digitalis glycosides. May enhance the rebound hypertension that can follow the withdrawal of clonidine. Potentiates the effect on atrial conduction time and induces a negative inotropic effect with class I antiarrhythmic agents (e.g. disopyramide) and amiodarone. May diminish the therapeutic effect of sympathomimetic agents (e.g. epinephrine). May potentiate the hypoglycaemic effects of insulin and oral antidiabetic agents. Concomitant use with NSAIDs (e.g. ibuprofen, indometacin) may decrease the hypotensive effect of atenolol. May increase the risk of hypotension and attenuate reflex tachycardia with anaesthetic drugs (e.g. methoxyflurane).

May cause a false-positive aldosterone/renin ratio.

Description:
Mechanism of Action: Atenolol competitively and selectively blocks β₁-adrenergic receptors but has little or no effect on β₂-receptors except at high doses. It has negative inotropic effects without intrinsic sympathomimetic and membrane-stabilising activities. Its mechanism of action in the treatment of hypertension is unclear but may be associated with reduction of cardiac rate and contractility.
Onset: β-blocking effect: ≤1 hour (oral).
Duration: β-blocking effect: 12-24 hours. Antihypertensive: 24 hours (oral).
Pharmacokinetics:
Absorption: Oral: Rapidly and incompletely absorbed from the gastrointestinal tract (approx 50%). Time to peak plasma concentration: 2-4 hours (oral); 5 minutes (IV).
Distribution: Poorly penetrates tissues; low concentration in brain tissue. Crosses the placenta and enters breast milk. Plasma protein binding: Approx 6-16%.
Metabolism: Undergoes little or no metabolism in the liver.
Excretion: Via urine (>85% [IV]; approx 40-50% as unchanged drug [oral]); faeces (as unchanged drug). Elimination half-life: Approx 6-7 hours.

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 2249, Atenolol. https://pubchem.ncbi.nlm.nih.gov/compound/Atenolol. Accessed May 26, 2022.

Store between 20-25°C.

Anti-Anginal Drugs / Beta-Blockers

C07AB03 - atenolol ; Belongs to the class of selective beta-blocking agents. Used in the treatment of cardiovascular diseases.

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Anon. Atenolol. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 05/04/2022.

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Tenormin 25 mg Tablets (Atnahs Pharma UK Limited). MHRA. https://products.mhra.gov.uk. Accessed 05/04/2022.

Tenormin 50 mg Film-coated Tablets (AstraZeneca Sdn. Bhd.). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 05/04/2022.

Tenormin Injection 0.5 mg/mL (Atnahs Pharma UK Limited). MHRA. https://products.mhra.gov.uk. Accessed 05/04/2022.

Tenormin Tablet (Almatica Pharma LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 05/04/2022.

Viatris Ltd. Atenolol Viatris, 50 mg and 100 mg, Film-coated Tablets data sheet 27 July 2021. Medsafe. http://www.medsafe.govt.nz. Accessed 05/04/2022.