Alonet Special Precautions

Atenolol should not be withdrawn abruptly. The dosage should be withdrawn gradually over a period of 7-14 days, to facilitate a reduction in beta-blocker dosage. Patients should be followed during withdrawal, especially those with ischaemic heart disease.
Atenolol may be used in patients whose signs of heart failure have been controlled, although it is contraindicated in uncontrolled heart failure. Caution must be exercised in patients whose cardiac reserve is poor.
Atenolol may increase the number and duration of angina attacks in patients with Prinzmetal's angina due to unopposed alpha-receptor mediated coronary artery vasoconstriction.
Due to its negative effect on conduction time, caution must be exercised if it is given to patients with first-degree heart block.
Atenolol may mask the symptoms of hypoglycaemia, in particular, tachycardia.
Atenolol may mask the signs of thyrotoxicosis.
Atenolol may cause a more severe reaction to a variety of allergens when given to patients with a history of anaphylactic reaction to such allergens. Such patients may be unresponsive to the usual doses of adrenaline (epinephrine) used to treat the allergic reactions.
Atenolol may cause a hypersensitivity reaction including angioedema and urticaria.
Although cardioselective (beta₁) beta-blockers may have less effect on lung function than non-selective beta-blockers, as with all beta-blockers, these should be avoided in patients with reversible obstructive airways disease, unless there are compelling clinical reasons for their use. Where such reasons exist, atenolol may be used with caution. Occasionally, some increase in airways resistance may occur in asthmatic patients however, and this may usually be reversed by commonly used dosage of bronchodilators such as salbutamol or isoprenaline.