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NEO-NACLEX Tablets 2.5mg: small, circular, white, biconvex tablets, 5.6mm in diameter, engraved 'NEO NACLEX 2.5 DF' on one face. Each tablet contains 2.5mg bendrofluazide.
NEO-NACLEX Tablets 5mg: circular, white, biconvex tablets, 6.4mm in diameter, engraved 'NEO NACLEX 5.0 DF' on one face. Each tablet contains 5mg bendrofluazide.
NEO-NACLEX inhibits the renal tubular absorption of salt and water. Sodium and chloride ions are excreted in equivalent proportions, and there is little or no disturbance of the acid/base equilibrium. There is no important effect upon carbonic anhydrase. NEO-NACLEX initiates diuresis in about 2 hours and maintains a steady diuresis lasting for about 12 hours.
The mechanism whereby the thiazides exert their antihypertensive effect has not been clearly established. In non-oedematous patients there may be little noticeable diuretic effect.
The following data apply to NEO-NACLEX tablets.
Since bendrofluazide is completely absorbed from the gastrointestinal tract and only about 30% is excreted unchanged in the urine, the majority of an oral dose being eliminated by non-renal mechanisms, it has been inferred that bendrofluazide is extensively metabolised. It has been suggested that metabolites, some of which may be active, accumulate during chronic treatment and compete with bendrofluazide for pathways of tubular secretion. Bendrofluazide is estimated to have a plasma half-life of about 3 or 4 hours, its biological half-life being much longer. It is 94% bound to human serum albumin in vitro. The time to reach peak concentration is 2 to 2.5 hours.
NEO-NACLEX is indicated in the treatment of oedema associated with conditions such as: congestive heart failure, nephrotic syndrome and cirrhosis of the liver.
NEO-NACLEX is indicated in the treatment of essential hypertension where it may be used as the sole antihypertensive agent, or as an adjunct to other medicines whose action it potentiates.
When bendrofluazide is added to other antihypertensive agents, the dosage of the latter can usually be reduced gradually as bendrofluazide takes effect.
Oedema: 5mg given orally once daily in the morning usually produces the desired effect without diuresis interfering with sleep, but this dose can be increased to 10mg if required. During the first few days of treatment there is usually a large increase in urinary volume, which diminishes as treatment continues.
Essential hypertension: 2.5mg to 10mg once daily, alone or in conjunction with other antihypertensive agents.
Maintenance: many patients will respond adequately to a daily dose of 2.5mg or 5mg on only two or three days in the week.
For children up to 12 years of age, 50-100 mcg/kg bodyweight daily.
Severe renal or hepatic failure, hypersensitivity to the product or other sulphonamide-like medicines, Addison's disease, diabetic keto-acidosis and hypercalcaemia.
Treatment with lithium carbonate.
When treatment with bendrofluazide is intensive or continuous, periodic estimations of serum electrolytes (especially potassium) should be carried out. Some loss of potassium may occur and, in these circumstances, potassium chloride supplements may be required in the following cases:
- if the patient is vomiting, has diarrhoea or is suffering from an acute febrile or chronic illness (especially cirrhosis of the liver or heart failure).
- to prevent hypokalaemia, possible arrhythmias and other ECG changes in patients receiving digitalis especially if diuretic treatment is prolonged.
- in patients at risk of myocardial infarction.
- in patients admitted for cardiac surgery.
- in patients receiving concurrent therapy with carbenoxolone or corticosteroids.
Potassium depletion may cause polyuria, malaise, muscle weakness or cramp, decreased tendon reflexes, anorexia, dizziness, nausea or vomiting. Also, sensitivity to digitalis may increase and signs of overdosage appear. Prolonged potassium deficiency may induce chronic pyelonephritis.
Potassium supplements must not be given in renal insufficiency complicated by hypokalaemia. In renal insufficiency, renal function should be monitored. In prolonged therapy it is necessary to test for glycosuria and investigate polyuria. The possibility of magnesium depletion should be considered.
In cirrhosis of the liver, thiazides may precipitate hepatic encephalopathy.
Thiazides may aggravate existing diabetes mellitus and cause symptoms in patients with latent disease. Bendrofluazide may impair control of diabetes in patients receiving sulphonylureas. Thiazides should be used with caution in systemic lupus erythematosus.
Serum uric acid levels may be raised in some patients, with or without gout.
Thiazides may cause or aggravate hyperlipidaemia.
The elderly are sensitive to the effects of thiazides on blood pressure and electrolytes. Administration of supplementary potassium is particularly important in the elderly. Patients with prostatic hypertrophy may develop acute urinary retention.
Diuretics are best avoided in the management of oedema of pregnancy or hypertension in pregnancy as their use may be associated with hypovolaemia, increased blood viscosity and reduced placental perfusion. There is inadequate evidence of safety in human pregnancy.
There are rare reports of foetal and neonatal bone marrow depression, thrombocytopenia, electrolyte imbalance, hypoglycaemia and jaundice.
Expectant mothers who receive thiazide diuretics may be at increased risk from acute haemorrhagic pancreatitis.
In parturition, thiazides may cause uterine inertia and delay the onset of labour.
Thiazides are only indicated in pregnancy if oedema complicates a pathological lesion and, even then, after assessing risk versus benefit including the undesirability of administering medicines in the first trimester.
As thiazide diuretics are secreted in mothers' milk, breast feeding should be avoided.
The following have been reported: disturbances of electrolyte, acid-base balance, lipids, glucose and uric acid levels; thirst, polyuria, weakness, dizziness, muscle cramps and reversible impotence; nausea, vomiting, mild anorexia, gastric irritation, diarrhoea or constipation; rashes, skin reactions, purpura and blood dyscrasias including thrombocytopenia; hypocalciuria, precipitation of gout, pancreatitis, hepatic encephalopathy and postural hypotension.
The renal clearance of lithium carbonate is reduced. Bendrofluazide should not be administered concurrently with lithium carbonate.
Bendrofluazide may impair control of diabetes in patients receiving sulphonylureas.
The hypotensive effect of halothane is increased by thiazides.
Sensitivity to tubocurarine is increased in hypokalaemia. Plasma potassium should be monitored prior to its use in thiazide-treated patients.
Carbenoxolone, indomethacin, phenylbutazone and corticosteroids may both antagonise the hypotensive effect of thiazides and increase potassium loss. Monitoring and potassium supplements are recommended.
Enhanced hypotensive effects may follow the concomitant use of thiazides and barbiturates, alcohol, other antihypertensives (eg. beta-blocking agents, ACE inhibitors, calcium antagonists), MAOIs or narcotics.
The use of allopurinol and thiazides in patients with renal dysfunction should be avoided: severe hypersensitivity vasculitis has been reported.
Hypokalaemia secondary to the use of thiazides may increase the toxicity of cardiac glycosides and antagonise the effect of anti-arrhythmics.
Caution is required in the use of thiazides with any medicine/disease state which has a potential for producing potassium imbalance.
CNS depression (eg. Drowsiness, lethargy and coma) may occur without cardiovascular or respiratory depression. Hypovolaemia, hypokalaemia and mild hypoglycaemia are likely to be present. In the case of recent ingestion, gastric lavage should be carried out; activated charcoal may help reduce absorption. Treatment should be symptomatic and directed at fluid and electrolyte replacement which should be monitored together with the blood pressure and renal function. Hyponatraemia should be treated with water deprivation rather than the administration of NaCI. Cathartics should be avoided.
Store below 25°C. Protect from light.
Prescription Only Medicine
Containers of 500 tablets.
Nil.
GlaxoSmithKline NZ Ltd
Quay Tower
Cnr Albert & Customs Streets
Private Bag 106600
Downtown
Auckland
NEW ZEALAND
Telephone: (09) 367 2900
Facsimile: (09) 367 2506
4 December 2002
NEO-NACLEX™ is a trade mark of the GlaxoSmithKline Group of Companies.
Issue 07