(and dosage form):
Each ADCO-LOTEN tablet contains atenolol 100 mg and chlorthalidone 25 mg.
A 7.1.3 Other Hypotensives.
Atenolol is a beta-adrenoceptor blocking agent which acts preferentially on beta-adrenergic receptors in the myocardium. Atenolol has no intrinsic activity and minimal membrane stabilising properties. It does not cross the blood-brain-barrier to a significant extent. Chlorthalidone is a thiazide diuretic. The thiazide diuretics act directly on the kidney to increase the excretion of sodium chloride and an accompanying volume of water, they also increase the excretion of potassium.
Management of mild to moderate hypertension.
Sensitivity to any of the active ingredients. ADCO-LOTEN should not be given to patients with bronchospasm or obstructive airways disease, metabolic acidosis, sinus bradycardia, or partial heart block. It should be given to patients with congestive heart failure only when they are fully digitalised and only then with great caution. It should never be given to patients with phaeochromocytoma without concomitant alpha adrenoceptor blocking therapy.
Great care should be exercised in administering ADCO-LOTEN to patients undergoing anaesthesia, and myocardial depressants such as halothane, cyclopropane, or ether should be avoided.
ADCO-LOTEN should not be used with myocardial depressant agents such as quinidine, procainamide, lignocaine or phenytoin which may enhance the effects of the atenolol. Nor should it be used with verapamil; neither medicine should be administered within several days of discontinuing the other.
Atenolol should not be used in patients with peripheral vascular disease and Raynauds Phenomenon.
Atenolol should not be used after prolonged fasting.
The normal dosage of ADCO-LOTEN should be reduced in elderly patients or in patients suffering from renal dysfunction.
In the peri-operative period, it is generally unwise to reduce the dosage of ADCO-LOTEN therapy to which the patient is accustomed, as there may be danger of aggravation of angina pectoris or hypertension during the surgical period. The patients normal tachycardiac response to hypovolaemia, or blood loss may be obscured during or after surgery by ADCO-LOTEN therapy. Particular caution should be taken in this regard.
Safety in pregnancy and lactation has not been established.
ADCO-LOTEN is not recommended for use in children.
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 the withdrawal of the beta-blocker as severe rebound hypertension may occur.
Atenolol is excreted into breast milk. Consult your physician.
DOSAGE AND DIRECTIONS FOR USE:
One tablet daily.
There is little or no further fall in blood pressure with increased dosage.
SIDE-EFFECTS AND SPECIAL PRECAUTIONS:
The most common adverse events experienced with atenolol are nausea, vomiting and other gastro-intestinal disturbances, fatigue and dizziness. Cardiovascular effects include bradycardia, hypotension, or paradoxical hypertension; cold extremities and Raynauds phenomenon; 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. Paraesthesia and loss of hearing have been reported. Bronchospasm may occur, particularly in susceptible individuals. Blood disorders and skin rashes may also occur. Other adverse events reported include impaired sexual function, allergic reactions, metabolic disturbances, fluid retention and mass gain, alopecia, myopathies, dry eyes, and stomatitis.
Chlorthalidone may provoke hyperglycaemia and glycosuria in diabetic and other susceptible patients. It may cause hyperuricaemia and precipitate attacks of gout in some patients. Administration of thiazide diuretics may be associated with electrolyte imbalances including hypochloraemic alkalosis, hyponatraemia, and hypokalaemia. Hypokalaemia intensifies the effect of digitalis on cardiac muscle and administration of digitalis or it's glycosides may have to be temporarily suspended. The urinary excretion of calcium is reduced. Hypomagnesaemia has also occurred.
Other side-effects occuring with chlorthalidone include anorexia, gastric irritation, nausea, vomiting, constipation, diarrhoea, headache, dizziness, postural hypotension, paraesthesia, impotence and yellow vision. Hypersensitivity reactions include skin rashes, photosensitivity, pulmonary oedema, and pneumonitis. Cholestatic jaundice, pancreatitis and blood dyscrasias including thrombocytopenia, granulocytopenia, leukopenia and aplastic and haemolytic anaemia have been reported.
Atenolol may mask the symptoms of hyperthyroidism and hypoglycaemia as well as enhancing the effects of hypoglycaemic agents in patients with diabetes mellitus.
The effects of atenolol are diminished by beta-adrenoceptor stimulating agents such as isoprenaline; the hypotensive effects 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.
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 currently taking a beta-blocker.
Chlorthalidone should be used with caution in patients with impaired hepatic function since they may increase the risk of hepatic encephalopathy. It should also be given with caution in renal impairment since it can further reduce renal function.
All patients should be carefully observed for signs of fluid and electrolyte imbalance especially in the presence of vomiting or during parenteral fluid therapy. Thiazides may exacerbate or activate systemic lupus erythematosus in susceptible patients.
Thiazide diuretics may enhance the neuromuscular blocking action of competitive muscle relaxants such as tubocurarine. They may enhance the effect of antihypertensive agents, while postural hypotension associated with thiazide diuretic therapy may be enhanced by concomitant ingestion of alcohol, barbiturates or opioids. The potassium-depleting effect of chlorthalidone may be enhanced by corticosteroids, corticotrophin or carbenoxolone.
Concomitant administration of thiazide diuretics and lithium is not generally recommended since the association may lead to toxic blood concentrations of lithium. Blood glucose concentrations should be monitored in patients taking antidiabetic agents since requirements might change.
Chlorthalidone may interfere with a number of diagnostic tests including tests for parathyroid function; serum concentrations of protein bound iodine may increase without signs of thyroid disturbance.
Treatment with chlorthalidone can inhibit lactation.
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.
Cases of mild overdose should be observed for at least four hours, as apnoea and cardiovascular collapse may appear suddenly.
Gastric lavage should be performed if within four hours of suspected overdose. 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 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.
With overdosage of chlorthalidone, treatment should be symptomatic and supportive and directed at fluid and electrolyte replacement.
ADCO-LOTEN tablets are round white film coated tablets.
Securitainers with 28 tablets.
Store below 25°C. Protect from light. Keep out of reach of children.
NAME AND BUSINESS ADDRESS OF THE APPLICANT:
Adcock Ingram Limited
Adcock Ingram Park
17 Harrison Ave
Private Bag X69
DATE OF PUBLICATION OF THIS PACKAGE INSERT:
18 December 1991
New addition to this site: April 2004
Source: Pharmaceutical Industry
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