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

Logo TEN-BLOKA 50 TABLETS
TEN-BLOKA 100 TABLETS

SCHEDULING STATUS:
S3

PROPRIETARY NAME
(and dosage form):

TEN-BLOKA 50 TABLETS
TEN-BLOKA 100 TABLETS

COMPOSITION:
Each tablet contains 50 or 100 mg of
Atenolol.

PHARMACOLOGICAL CLASSIFICATION:
A 5.2 Adrenolytics (Sympatholytics).

PHARMACOLOGICAL ACTION:
Ten-bloka (atenolol) is a cardioselective beta1-adrenergic blocking agent, with insignificant partial agonist activity and weak membrane-stabilizing properties. It is incompletely absorbed when administered orally and is excreted largely unchanged in the urine. Ten-bloka has a half-life in plasma of approximately 6 to 8 hours. As Ten-bloka is highly hydrophilic it does not readily cross the blood-brain barrier.

INDICATIONS:
Ten-bloka is used in the management of angina pectoris and hypertension.

CONTRA INDICATIONS:
Ten-bloka should not be given to patients with partial heart block, and should never be given to patients with phaeochromocytoma without concomitant alpha-adrenoceptor blocking therapy. It should not be given together with verapamil or within several days of discontinuing treatment and vice versa.
Ten-bloka is contra-indicated in patients with bronchial asthma, bronchitis, bronchospasm or chronic respiratory diseases, a history of obstructive airways disease, metabolic acidosis, atrioventricular block, marked bradycardia, (less than 50 per minute), sinus bradycardia, partial heart block heart failure refractory to digitalis, uraemia, pregnancy, lactation, hypoglycaemia, second and third degree heart block, peripheral vascular diseases and Raynaud's phenomenon.
Ten-bloka should not be given to patients with heart failure unless the heart failure is controlled and even then great care is still necessary.
It is contra-indicated after prolonged fasting.
Hypersensitivity to any of the ingredients.
In patients with cardiogenic shock.

WARNING:
Ten-bloka should be given to patients with congestive heart failure only when they are fully digitalised and only then with great caution. Great care should be exercised in giving Ten-bloka to patients undergoing general anaesthesia, and myocardial depressants, such as chloroform and ether must be avoided.
Atenolol is excreted into breast milk. Consult your physician.

DOSAGE AND DIRECTIONS FOR USE:
Angina Pectoris
The usual dose is 100 mg daily, given as a single or divided dose. It is unlikely that additional benefit will be obtained by increasing the dose.
Hypertension
The usual dose is 100 mg daily, as a single dose. It is unlikely that additional benefit will be obtained by increasing the dose.
The dosage should be decreased in patients with severe impairment of renal function.
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.

SIDE-EFFECTS AND SPECIAL PRECAUTIONS:
Side-effects
Adverse gastro-intestinal effects include nausea and vomiting, diarrhoea, constipation and abdominal cramping. Fatigue and dizziness also occur. Cardiovascular effects include bradycardia, hypotension, or paradoxical hypertension, cold extremities and Raynaud's phenomenon and congestive heart failure or heart block may be precipitated in patients with underlying cardiac disorders.
Central nervous system effects include depression, hallucinations, confusion, psychotic episodes, and disturbances of sleep and vision. Paraesthesia and loss of hearing have been reported.
Blood disorders, nonthrombocytopenic purpura, thrombocytopenia, transient eosinophilia and less frequently agranulocytosis may also occur. Other adverse effects reported include impaired sexual function, allergic reactions, skin rashes, pruritus, metabolic disturbances, fluid retention and weight gain, reversible alopecia, myopathies and stomatitis.
Decreased tear production, blurred vision and soreness are among the ocular symptoms which have been reported.
Other adverse effects reported include a lupus-like syndrome, male impotence, sclerosing peritonitis and retroperitoneal fibrosis. Bronchospasm may be precipitated in susceptible patients due to blockade of beta2 receptors in bronchial smooth muscle. Pneumonitis, pulmonary fibrosis and pleurisy have also been reported.
Metabolic changes affect glucose control and cholesterol concentrations.
Pareasthesia, peripheral neuropathy and myopathies have been reported.
Side-effects may be minimised by starting treatment with a small dose and gradually increasing, although serious reactions have been reported after small doses.
Abrupt withdrawal of beta blockers may exacerbate angina and may lead to sudden death.
Special precautions
Atenolol may mask the symptoms of hyperthyroidism. It may also mask the symptoms of hypoglycaemia, as well as enhancing the effects of hypoglycemic agents in patients with diabetes mellitus.
Ten-Bloka may unmask myasthenia gravis. Psoriasis may be aggravated.. Patients with a history of anaphylaxis to an antigen may be more reactive to repeated challenge with the antigen while taking atenolol.
The normal dose should be reduced in elderly patients, or in patients suffering from renal or hepatic dysfunction.
In the peri-operative period, it is generally unwise to reduce the dosage to that which the patient is accustomed, as there may be danger of aggravation of angina pectoris or of hypertension. A patients normal tachycardiac response to hypovolaemia or blood loss may be obscured during or after surgery. Particular caution should be taken in this regard.
Important
Digitalization of patients receiving long-term beta-blocker therapy may be necessary if congestive heart failure is likely to develop. This combination can be considered despite the potentiation of the 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.
Abrupt discontinuation of therapy has sometimes resulted in angina, myocardial infarction, ventricular arrhythmias and death. Discontinuation of therapy should be gradual over a period of one to two weeks and patients should be advised to limit the extent of their physical activity during the period that the medicine is being discontinued.
Administration to pregnant mothers shortly before giving birth, or during labour may result in the newborn infants being born hypotonic, collapsed and hypoglycaemic.
Administration of Ten-Bloka to pregnant women shortly before delivery has ocassionally resulted in bradycardia and other adverse effects in the Neonate.
Ten-bloka should not be administered to patients with phaeochromocytoma without concurrent alpha-adrenergic blocking therapy. If Ten-bloka 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.
INTERACTIONS:
The effects of other myocardial depressant agents, including anti-arrhythmics such as quinidine, procainamide, or lignocaine, phenytoin, and medicines which interfere with calcium transport, such as verapamil, may also be enhanced by atenolol.
The effects of atenolol are diminished by beta-adrenoceptor stimulating agents such as isoprenaline; the hypotensive effects of atenolol may be dangerously reversed and the peripheral vasoconstrictor effects enhanced by alpha-adrenoceptor stimulating agents such as noradrenaline or those with mixed alpha-and beta-adrenoceptor stimulating properties such as adrenaline; bradycardia may also occur.
Anaesthetics agents causing myocardial depression, such as ether, cyclopropane, and trichloroethylene are best avoided and anaesthetists should be made aware that Ten-Bloka are being taken.
Bradycardia, cardiac arrest, and ventricular fibrillation have been reported after initiation of beta-blocker treatment in patients receiving amiodarone.
Serum-atenolol concentrations were reduced by concurrent administration of ampicillin given in oral doses of 1 gram.
The effects of atenolol may be enhanced by adrenergic neurone blocking agents such as guanethidine or bethanidine, or catecholamine-depleting agents such as reserpine, and the hypotensive effects by diuretics.
Atenolol may enhance some of the cardiac effects of digitalis and diminish others. It has been suggested that clonidine withdrawal symptoms may be exacerbated in patients who are concurrently taking a beta-blocker.
Please note: Such interactions can have life-threatening consequences.
Concurrent administration of calcium-channel blockers and beta blockers has resulted in hypotension, bradycardia, conduction defects, and cardiac failure. Ten-Bloka should be avoided in combination with cardio-depressant calcium-channel blockers such as verapamil and diltiazem. Heart failure and severe hypotension have been reported in combination with Nifedipine. Reduced clearance of disopyramide by concomitant administration of atenolol has occurred.
There is an increased risk of peripheral vasoconstriction during concomitant administration of ergotamine and beta blockers.
The anti-hypertensive effect of beta blockers may be impaired by concurrent administration of some nonsteroidal anti-inflammatory medicines, possibly due to their inhibition of renal synthesis of vasodilatory prostaglandins.

KNOWN SYMPTOMS OF OVERDOSAGE AND PARTICULARS OF ITS TREATMENT:
Overdosage with atenolol may produce bradycardia and severe hypotension. Bronchospasm and heart failure may be produced in certain individuals.
Coma and convulsions have been reported following beta-blocker overdosage.
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 if within 4 hours of suspected overdose. Repeated activated charcoal is necessary in severe overdosage.
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 may be required to counteract the beta-blockade. Transvenous-cardiac pacing may be required for severe bradycardia. Bronchospasm should be treated with intravenous aminophylline or inhaled, or intravenous beta-agonist, eg salbutamol.

IDENTIFICATION:
50 mg tablet: A white, film-coated, biconvex tablet, bisected on one side and engraved with "TEN-BLOKA 50" on the other side.
100 mg tablet: An orange-red, film coated, biconvex tablet, bisected on one side and engraved with "TEN-BLOKA 100" on the other side.

PRESENTATION:
Ten-Bloka 50: Securitainers of 30 and 500 tablets.
Ten-Bloka 100: Securitainers of 28 and 500 tablets.

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

REGISTRATION:
50 mg tablets:         V/5.2/56
100 mg tablets:         V/5.2/57

NAME AND BUSINESS ADDRESS OF APPLICANT:
Pharmacare Limited
7 Fairclough Road
Korsten
PORT ELIZABETH
6020.

DATE OF PUBLICATION OF THIS PACKAGE INSERT:
11/07/1991

                D745
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Updated on this site: May 2002
Current: September 2004
Source: Community Pharmacy

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