BENDROFLUMETHIAZIDE Tablet Ref.[6440] Active ingredients: Bendroflumethiazide

• Bendroflumethiazide may raise serum uric acid levels with consequent exacerbation of gout in susceptible patients.
• Thiazide diuretics should be used with caution in patients with mild or moderate renal or hepatic dysfunction. Renal function should be monitored during bendroflumethiazide therapy. Thiazides can cause electrolyte imbalance which is more severe in patients with hepatic and renal impairment and in those receiving higher or prolonged doses. Elderly patients and those on long term treatment need regular blood tests to monitor electrolyte levels. Hypokalaemia should be corrected by adding potassium supplements to the regimen. The risk of hypomagnesaemia is increased in alcoholic cirrhosis.
• Thiazides may decrease urinary calcium excretion and may cause intermittent and slight elevation of serum calcium. Marked hypercalcaemia may be evidence of hidden hyperparathyroidism. Thiazides should be discontinued before carrying out tests for parathyroid function
• Systemic lupus erythematosus (SLE) may be exacerbated by bendroflumethiazide.
• Diabetes Mellitus may be aggravated by bendroflumethiazide.
• Caution is required when treating patients with porphyria.
• Patients taking pimozide or thioridazine. (see section 4.5)
• Patients with rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption should not take this medicine.

Allopurinol: Bendroflumethiazide may antagonise the action of allopurinol by causing retention of urate in the kidney. Caution is advised when using this combination.

Anion exchange resins: Colestyramine and colestipol reduce absorption of bendroflumethiazide. This can be prevented by leaving an interval of two hours between doses of bendroflumethiazide and the anion exchange resin.

Antiarrhythmics: The cardiotoxicity of disopyramide, amiodarone, flecainide and quinidine is increased if hypokalaemia occurs following the administration of bendroflumethiazide. The actions of lidocaine and mexiletine are antagonised by hypokalaemia.

Antidepressants: There is an increased risk of postural hypotension if bendroflumethiazide is given with tricyclic antidepressants. There may also be a risk of hypokalaemia if thiazides are given with reboxetine. Concomitant use with MAOIs may result in an enhanced hypotensive effect.

Antidiabetics: Bendroflumethiazide antagonises the hypoglycaemic effects of sulfonylureas, with a potential loss of diabetic control.

Antiepileptics: There is an increased risk of hyponatraemia when bendroflumethiazide and carbamazepine are take concurrently.

Antifungals: The risk of hypokalaemia is increased when amphotericin and bendroflumethiazide are taken concurrently.

Antihypertensives: Bendroflumethiazide may enhance the antihypertensive effect of ACE inhibitors and angiotensin-II antagonists. There is an increased risk of first dose hypotension if prazosin is given to a patient taking bendroflumethiazide.

Antipsychotics: Hypokalaemia increases the risk of ventricular arrhythmias with pimozide or thioridazine so concomitant use should be avoided.

Calcium salts: Bendroflumethiazide reduces urinary excretion of calcium so there is an increase risk of hypercalcaemia when calcium salts are taken concurrently. Serum calcium levels should be monitored to ensure that they do not become excessive.

Calcium channel blockers and peripheral vasodilators: The hypotensive effect of calcium channel blockers and moxisylyte may be enhanced when co-administered with bendroflumethiazide.

Corticosteroids: Corticosteroids may exacerbate hypokalaemia associated with bendroflumethiazide and its diuretic activity may be antagonised.

Cytotoxics: Concomitant use with cisplatin can lead to an increased risk of nephrotoxicity and ototoxicity.

Digoxin: The hypokalaemic effect of bendroflumethiazide may enhance sensitivity to digoxin when taken concurrently. Patients should be monitored for signs of digoxin intoxication, especially arrhythmias. The dose of digoxin should be reduced and potassium supplements given, should digoxin toxicity develop.

Hormone antagonists: There is an increased risk of hyponatraemia when bendroflumethiazide is used concomitantly with aminoglutethamide. Bendroflumethiazide can cause an increased risk of hypercalcaemia when co-administered with toremifene.

Lithium: Bendroflumethiazide inhibits the tubular elimination of lithium, resulting in an elevated plasma lithium concentration and risk of toxicity. Plasma lithium concentrations must be monitored when these drugs are given concurrently.

Muscle relaxants: The hypotensive activity of bendroflumethiazide may be increased by baclofen and tizanidine. Bendroflumethiazide may enhance the neuromuscular blocking activity of non-depolarising muscle relaxants, such as tubocurarine, gallamine, alcuronium and pancuronium.

NSAIDs: Bendroflumethiazide may enhance the nephrotoxicity of NSAIDs. Indometacin and ketorolac antagonise the diuretic effect of bendroflumethiazide, this occurs to a lesser extent with ibuprofen, piroxicam and naproxen. The effects of concurrent use should be monitored and the dose of bendroflumethiazide modified if necessary.

Oestrogens and progestogens: Oestrogens and combined oral contraceptives antagonise the diuretic effect of bendroflumethiazide.

Sympathomimetics: Sympathomimetics can cause hypokalaemia. The risk of serious heart arrhythmias in asthmatic patients may be increased if bendroflumethiazide is added to their medication.

Theophylline: Concomitant administration of theophylline and bendroflumethiazide increases the risk of hypokalaemia.

Ulcer healing drugs: There is an increased risk of hypokalaemia and a decrease in diuretic activity when carbenoxolone and bendroflumethiazide are taken together. Patients should be monitored and given potassium supplements when required.

Vitamins: The risk of hypercalcaemia is increased if bendroflumethiazide is given with vitamin D.

Pregnancy

Bendroflumethiazide is best avoided for the management of oedema or hypertension in pregnancy as it crosses the placenta and its use may be associated with hypokalaemia, increased blood viscosity and reduced placental perfusion.

There is insufficient evidence of safety in human pregnancy and foetal bone marrow depression, thrombocytopenia and neonatal jaundice have been described.

Breast-feeding

Bendroflumethiazide suppresses lactation and, although the amounts passing into breast milk are small, it should be avoided in breast feeding mothers.

As bendroflumethiazide can cause dizziness, patients should make sure they are not affected before driving or operating machinery.

The following undesirable effects have been divided into the following categories: Very common: ≥1/10, Common: ≥1/100 to <1/10, Uncommon: ≥1/1,000 to<1/100 Rare: ≥1/10,000 to <1/1,000, Very rare: <1/10,000, not known (cannot be estimated from the available data).

Blood and the lymphatic system disorders

Rare:__ blood dyscrasias, including agranulocytosis, aplastic anaemia, thrombocytopenia and leucopenia

Immune system disorders

Not known: Rashes (including exfoliative dermatitis), photosensitivity, pneumonitis and pulmonary oedema have been reported occasionally.

Metabolism and nutrition disorders

Not known: Bendroflumethiazide may lower carbohydrate tolerance and the insulin dosage of some diabetic patients may require adjustment. Care is required when bendroflumethiazide is administered to patients with a known predisposition to diabetes. Bendroflumethiazide may raise serum uric acid levels and exacerbate gout in susceptible individuals. Plasma lipids may be altered in patients taking bendroflumethiazide.

Bendroflumethiazide administration may cause hypokalaemia, hypomangnesaemia, hyponatraemia, hypercalcaemia and hypochloraemic alkalosis. Hypokalaemia may result in polyuria, malaise, muscle weakness or cramp, dizziness, nausea, anorexia or vomiting.

Nervous system disorders

Not known: Dizziness

Vascular disorders

Not known: Postural hypotension.

Gastrointestinal disorders

Not known: Nausea, vomiting, diarrhoea, constipation and gastric irritation.

Hepatobiliary disorders

Not known: Pancreatitis, intrahepatic cholestasis

Reproductive system and breast disorders

Not known: impotence (reversible on discontinuing the drug)

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme; website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.

None known.