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

Logo ATENOBLOK 100 TABLETS
ATENOBLOK 50 TABLETS

SCHEDULING STATUS:
S3

PROPRIETARY NAME
(and dosage form):

ATENOBLOK 100 TABLETS
ATENOBLOK 50 TABLETS

COMPOSITION:
ATENOBLOK 100:
Atenolol 100 mg per tablet.
ATENOBLOK 50: Atenolol 50 mg per tablet.

PHARMACOLOGICAL CLASSIFICATION:
A 5.2 Adrenolytics (sympathicolytics)

PHARMACOLOGICAL ACTION:
Atenolol is a beta1-selective antagonist which acts preferentially on beta-adrenergic receptors in the heart.
It has no intrinsic sympathomimetic nor membrane stabilising activity.
Absorption of atenolol following oral dosing is consistent but incomplete (approximately 40 - 50%) with peak plasma concentrations occurring 2 - 4 hours after dose. The plasma half-life is about 6 hours but this may rise in severe renal impairment since the kidney is the major route of elimination.
Atenolol is very hydrophilic and appears to penetrate the brain to only a limited extent.

INDICATIONS:
Management of angina pectoris and hypertension. Myocardial infarction, early intervention in the acute phase.

CONTRA-INDICATIONS:
Hypersensitivity to any of the ingredients.
ATENOBLOK should not be given to patients with bronchospasm or asthma or to those with a history of obstructive airways disease. Other contra-indications include metabolic acidosis, sinus bradycardia or partial heart block. ATENOBLOK should not be given to patients with congestive heart failure unless their heart failure is controlled and even then great care is still necessary.
Similarly patients with phaeochromacytoma should not receive ATENOBLOK without concomitant alpha-adrenoceptor blocking therapy.
Contra-indicated in patients with cardiogenic shock, contra-indicated after prolonged fasting.
Pregnancy: Atenolol crosses the placental barrier and appears in cord blood.
Administration to pregnant women has been associated with intra-uterine growth retardation.
Administration of atenolol to pregnant mothers shortly before giving birth or during labour may result in the newborn infants being born hypotonic, collapsed and hypoglycaemic.
Lactation: There is significant accumulation in breast milk. Breast-feeding patients must not take atenolol.

WARNINGS:
While taking atenolol, patients with a history of anaphylactic reactions to a variety of allergens, may have a more severe reaction on repeated challenge. Such patients may be unresponsive to the usual dose of adrenaline used to treat allergic reactions.
Particular caution should be exercised with patients suffering from the following: Bradycardia of less than 50 pulse beats per minute, peripheral vascular disease and Raynaud's phenomenon.
The normal dose should be reduced in elderly patients or in patients suffering from renal dysfunction.
Elderly patients may not respond as well to atenolol as younger patients.
In the peri-operative period it is generally unwise to reduce the dosage to which the patient is accustomed as there may be danger of aggravation of angina pectoris or of hypertension. A patient's normal tachycardiac response to hypovolemia or blood loss may be obscured during or
after surgery. Particular caution should be taken in this regard.

DOSAGE AND DIRECTIONS FOR USE:
Hypertension:
In the treatment of hypertension atenolol is given by mouth in a dose of 50 - 100 mg daily as a single dose, although 50 mg daily is generally adequate. The full effect is usually evident within 1 - 2 weeks.
Angina Pectoris:
The usual dose for angina pectoris is 50 - 100 mg daily given as a single dose or in divided doses.
Although up to 200 mg daily has been given for angina pectoris, additional benefit is not usually obtained from higher doses of atenolol.
When control is achieved after emergency treatment of cardiac arrhythmias with IV injection of atenolol, maintenance doses of 50 - 100 mg daily may be given by mouth.
Reduced doses may be required in patients with impaired renal function, as follows. When creatinine clearance is 15 to 35 mL per minute suggested doses are 50 mg daily by mouth or 10 mg once every two days intravenously. When creatinine clearance is less than 15 mL per minute suggested doses are 25 mg daily or 50 mg on alternate days by mouth or 10 mg once every four days intravenously.

SIDE-EFFECTS AND SPECIAL PRECAUTIONS:
Adverse effects:
Among the most serious adverse effects are heart failure, heart block and bronchospasm. Troublesome subjective side-effects include fatigue and coldness of the extremities.
Cardiovascular effects include bradycardia and hypotension; congestive heart failure or heart block maybe precipitated in patients with underlying cardiac disorders.
Abrupt withdrawal of ATENOBLOK may exacerbate angina and may lead to sudden death.
Pneumonitis, pulmonary fibrosis and pleurisy have also been reported.
Central nervous system effects include depression, hallucinations confusion and sleep disturbances. Fatigue is a common side-effect experienced with ATENOBLOK. Paraesthesia, peripheral neuropathy and myopathies have been reported.
Adverse gastro-intestinal effects include nausea and vomiting, diarrhoea, constipation, and abdominal cramping.
Skin rash, pruritus and reversible alopecia have occurred with the use of ATENOBLOK.
Decreased tear production, blurred vision and soreness are among the ocular symptoms which have been reported.
Haematological reactions include non-thrombocytopenia purpura, thrombocytopenia, and rarely agranulocytosis. Transient eosinophilia can occur.
Metabolic changes affect glucose control and cholesterol concentrations.
Abrupt withdrawal of ATENOBLOK has sometimes resulted in angina, myocardial infarction, ventricular arrhythmias and death. Patients undergoing long-term treatment with ATENOBLOK should have their medication discontinued gradually over a period of 1-2 weeks. Some authorities have advocated their gradual and temporary withdrawal prior to anaesthesia in order to provide better control of the circulatory system. If ATENOBLOK is not discontinued prior to anaesthesia, an agent such as atropine may be given to counter increases in vagal tone.
Precautions:
ATENOBLOK may mask the symptoms of hyperthyroidism and of hypoglycaemia. They may unmask myasthenia gravis. Psoriasis may be aggravated. Elderly patients with hypertension may not respond as well to ATENOBLOK as younger patients.
The dose may need to be reduced in patients with renal or hepatic dysfunction.
Interactions:
Care should be taken when using anaesthetic agents with atenolol. The anaesthetist should be informed.
It can be dangerous to administer this medicine concomitantly with the following medicines: hypoglycaemic agents, phenothiazines and Class I anti-arrhythmic agents such as disopyramide.
Such interactions can have life-threatening consequences.
Special note: Digitalisation of patients receiving long term atenolol therapy may be necessary if congestive cardiac failure is likely to develop. This combination can be considered despite the potentiation of the negative chronotropic effect of the two medicines. Careful control of dosages and of the individual patient's response (and notably pulse rate) is essential in this situation.
Combined use of atenolol and calcium channel blockers with negative inotropic effects eg verapamil and diltiazem can lead to an exaggeration of these effects particularly in patients with impaired ventricular function and/or SA or AV conduction abnormalities. Neither medicine should be administered intravenously within 48 hours of discontinuing the other.
Patients with a phaeochromocytoma require treatment with an alpha-adrenergic blocker.
If atenolol and clonidine are given concurrently the clonidine should not be discontinued until several days after the withdrawal of the atenolol as severe rebound hypertension may occur.

KNOWN SYMPTOMS OF OVERDOSAGE AND PARTICULARS OF ITS TREATMENT:
Coma and convulsions have been reported following ATENOBLOK overdosage.
Overdosage 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 least 4 hours, as apnoea and cardiovascular collapse may appear suddenly.
Gastric lavage should be performed within 4 hours of suspected overdosage. Repeated activated charcoal is necessary in severe overdoses.
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 isoprenaline maybe 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:
ATENOBLOK 100: White, round, flat-faced, bevelled tablet with "5778" printed on one side and DAN above 100 on the other side.
ATENOBLOK 50: White, round, flat-faced, bevelled tablet with "5777" printed on one side and
DAN above 50 on the other side

PRESENTATION:
ATENOBLOK 100 are packed in 30's, in white polypropylene containers with white caps.
ATENOBLOK 50 are packed in 30's, in white polypropylene containers with white caps.

STORAGE CONDITIONS:
Store below 25°C. Protect from light and moisture.
KEEP OUT OF REACH OF CHILDREN.

REGISTRATION NUMBERS:
ATENOBLOK 100:         30/5.2/0409
ATENOBLOK 50:         30/5.2/0408

NAME AND BUSINESS ADDRESS OF THE APPLICANT:
TRIOMED (Pty) Ltd
6B Phumelela Park
Montague Drive
Montague Gardens

DATE OF PUBLICATION OF THIS PACKAGE INSERT:
March 1997.

        PS032/A
        Britepak

Current: September 2003
Source: Community Pharmacy

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