INDICATIONS     CONTRA-INDICATIONS     DOSAGE     SIDE-EFFECTS     PREGNANCY     OVERDOSE     IDENTIFICATION     PATIENT INFORMATION

Logo HEXA-BLOK 50 mg TABLETS
HEXA-BLOK 100 mg TABLETS

SCHEDULING STATUS:
S3

PROPRIETARY NAME
(and dosage from):

HEXA-BLOK 50 mg TABLETS
HEXA-BLOK 100 mg TABLETS

COMPOSITION:
HEXA-BLOK 50 mg tablets containing 50 mg
atenolol.
HEXA-BLOK 100 mg tablets containing 100 mg atenolol.

PHARMACOLOGICAL CLASSIFICATION:
HEXA-BLOK is a beta-adrenoceptor blocking drug which acts preferentially on beta-adrenergic receptors in the heart. It has no intrinsic sympathomimetic or membrane stabilising activity. HEXA-BLOK (atenolol) is very hydrophilic and appears to penetrate the brain to only a limited extent.

INDICATIONS:
Management of angina pectoris and hypertension.

CONTRA-INDICATIONS:
HEXA-BLOK should not be used:
- in the presence of second or third degree heart block.
- with verapamil and neither drug should be administered within several days of discontinuing the other.
- after prolonged fasting.
- in patients with metabolic acidosis (e.g. in diabetes).
- in congestive heart failure unless or until signs of failure are controlled with digitalis.
HEXA-BLOK should not be given to patients suffering from the following:
asthma, bronchitis, chronic respiratory diseases, heart-block and bradycardia of less than 50 pulse beats per minute.
HEXA-BLOK must never be given to patients with a phaeochromocytoma without concomitant alpha-adrenergic blocker therapy.

WARNINGS:
Caution should be exercised when transferring a patient from clonidine. The withdrawal of clonidine may result in the release of large amounts of catecholamines which may give rise to a hypertensive crisis.
If beta-blockers are administered in these circumstances the unopposed alpha receptor stimulation may potentiate this effect.
If a beta-blocker and clonidine are given concurrently, the clonidine should not be discontinued until several days after withdrawal of the beta-blocker as severe rebound hypertension may occur.
Atenolol is excreted into breast milk. Please consult your physician.

DOSAGE AND DIRECTIONS FOR USE:
HEXA-BLOK is compatible with diuretics and other hypotensive agents.
Angina pectoris:
The usual dose is 50 mg to 100 mg daily given as single or divided doses.
Additional benefit is not usually obtained from higher doses of atenolol.
Hypertension:
The initial dose for the treatment of hypertension is usually 50 mg per day given once daily. If an adequate therapeutic response is not evident within several weeks the daily dose may be increased to 100 mg. Higher doses are unlikely to provide any greater anti-hypertensive effect.
In refractory cases a further reduction of blood pressure may be achieved by combining HEXA-BLOK with other anti-hypertensive agents for example co-administration of HEXA-BLOK with a diuretic.

SIDE-EFFECTS AND SPECIAL PRECAUTIONS:
Side-effects
Common side-effects are nausea, vomiting and other gastro-intestinal disturbances, fatigue and dizziness.
Cardiovascular effects include bradycardia, hypotension or paradoxical hypertension, cold extremities and Raynaud’s phenomenon (due to unopposed arteriolar alpha-sympathetic tone). Less frequently severe peripheral vascular disease and even peripheral gangrene may be precipitated. Congestive heart failure or heart block may be precipitated.
Central nervous system effects include depression, hallucinations, confusion, psychotic episodes and disturbances of sleep and vision.
Paraesthenia and loss of hearing have been reported. Blood disorders and skin rashes may also occur.
Other adverse effects reported include allergic reactions, metabolic disturbances including hypoglycaemia, fluid retention and mass gain, alopecia, myopathies, dry eyes, stomatitis, sexual impotence and skeletal muscle weakness.
Bronchoconstriction may occur in patients suffering from asthma, bronchitis and other chronic pulmonary diseases when HEXA-BLOK is administered.
Abrupt discontinuation of therapy with HEXA-BLOK may cause exacerbation of angina pectoris in patients suffering from ischaemic heart disease.
The administration of beta-blockers to pregnant mothers shortly before gibing birth or during labour has resulted in the newborn infants being born hypnotic, collapsed and hypoglycaemic.
NOTE: Adverse reactions to beta-blockers are more common in elderly patients with renal decompensation and in patients who receive the drug intravenously.
Interactions
Interactions may occur when beta-blocking agents are administered in conjunction with digitalis (potentially dangerous bradycardia and heart block may result), antediabetic agents including insulin and the oral hypoglycaemic agents, the phenothiazines (the phenothiazines and the beta-blockers have hypotensive effects which could be additive), quinidine (both may have a negative inotropic action on the heart) and other antiarrhythmic agents such as procainamide, lignocaine and verapamil.
Special note: Digitalisation of certain patients receiving long-term beta-blocker therapy can be valuable, particularly in those patients in whom congestive cardiac failure is likely to develop. This combination can be considered despite the potentiation of negative chronotropic effects of the two medicines. Careful control of dosages and of the individual patient’s response (and notably pulse rate) is essential in this situation.
Special precautions:
Particular caution should be exercised in administering HEXA-BLOK to patients suffering from peripheral vascular diseases and from Raynaud’s phenomenon.
The normal dose of HEXA-BLOK should be reduced in elderly patients and in patients suffering from renal dysfunction. In the perioperative period it is generally unwise to reduce the dosage of HEXA-BLOK therapy to which the patient is accustomed as there may be danger of aggravation of angina pectoris or of hypertension during the surgical period. A patient’s normal tachycardic response to hypovolaemia or blood loss may be obscured during or after surgery by beta-blocker therapy. Particular caution should be taken in this regard.
Discontinuation of therapy with beta-blockers should be gradual rather than abrupt and patients are advised to limit the extent of their physical activity during the period that the medicine is being discontinued.

KNOWN SYMPTOMS OF OVERDOSAGE AND PARTICULARS OF ITS TREATMENT:
Overdosage with HEXA-BLOK may produce bradycardia and severe hypotension. Bronchospasm and heart failure may be produced in certain individuals. Cases of mild overdose should be observed for at lease 4 hours as apnoea and cardiovascular collapse may appear suddenly. Gastric lavage should be performed if within 4 hours of suspected overdose. Repeated activated charcoal is necessary in severe overdose.
Atropine may be used to treat bradycardia. If the response is inadequate, glucagon may be given intravenously. Alternatively, dobutamine or isoprenaline may be used for the management of hypotension. Large doses of insoprenaline may be required to counteract the beta-blockade. Transvenous cardiac pacing may be required for severe bradycardia. Bronchospasm should be treated with IV aminophylline or inhaled or IV beta-agonist, e.g. Salbutamol.

IDENTIFICATION:
HEXA-BLOK 50 mg is a round, white, film-coated tablet and scored on one side.
HEXA-BLOK 100 mg is a round, white, film-coated tablet and scored on one side.

PRESENTATION:
HEXA-BLOK 50 mg is in calender packs of 30 tablets.
HEXA-BLOK 100 mg is in calender packs of 30 tablets.

STORAGE INSTRUCTIONS:
Store in well-closed containers below 25°C.
KEEP OUT OF REACH OF CHILDREN.

REGISTRATION NUMBER:
HEXA-BLOK 50 mg - 27/5.2/0468
HEXA-BLOK 100 mg - 27/5.2/0469

NAME AND BUSINESS ADDRESS OF THE APPLICANT:
Hexal Pharma (SA) (PTY) Ltd
Unit A
10 Fangio Road
Mahogany Ridge
Westmead

DATE OF PUBLICATION OF THIS PACKAGE INSERT:
October 1993

Updated on this site: February 2000

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