Bendroflumethiazide is a thiazide diuretic. Thiazides are moderately potent diuretics and exert their diuretic effect by reducing the reabsorption of electrolytes from the renal tubules, thereby increasing the excretion of sodium and chloride ions, and consequently water.
They act mainly at the beginning of the distal tubules. The excretion of further electrolytes notably potassium and magnesium, is also increased. The excretion of calcium is reduced. Their hypotensive effects is probably partly due to a reduction in peripheral resistance; they also enhance the effects of other antihypertensives. Paradoxically, thiazides have an antidiuretic effect in patients with diabetes insipidus.
Bendroflumethiazide has been reported to be completely absorbed from the gastro-intestinal tract and to have a plasma half-life of about 3 or 4 hours. It is highly bound to plasma proteins. There are indications that Bendroflumethiazide is fairly extensively metabolized about 30% is excreted unchanged in the urine.
Benduric is used in the treatment of oedema, including that associated with heart failure and for hypertension. Other indications have included the suppression of lactation. It is used for hypertension either alone or with other antihypertensives such as ACE inhibitors and beta blockers.
Dosage and administration
Adults: 2.5 mg daily, either alone or with other antihypertensives. In the treatment of Oedema dose is 5 to 10 mg by mouth daily or on alternative days; in some cases initial dose of up to 20 mg may be necessary.
Children: Initial dose for children is up to 400mcg per kg weight, daily reduced to 50 to 100mcg per kg for maintenance.
All diuretics produce changes in fluid and electrolyte balance. They should be used with caution in patients with existing fluid and electrolyte disturbances or who are at risk from changes in fluid and electrolyte balance, such as the elderly.
They should be avoided in patients with severe hepatic impairment, in whom encephalopathy may be precipitated. Patients with hepatic cirrhosis are also more likely to develop hypokalemia. All patients should be carefully observed for signs of fluid and electrolyte imbalance, especially in the presence of vomiting or during parenteral fluid therapy. Thiazide diuretics should not be given to patients with Addison’s disease. Diuretics should also be given with caution in renal impairment.
Bendroflumethiazide and other thiazides may cause a number of metabolic disturbances especially at high doses. They may provoke hyperglycemia and glycosuria in diabetic and other susceptible patients. They may cause hyperuricaemia and precipitate attacks of gout in some patients.
Other adverse effects include anorexia, gastric irritation, nausea, vomiting, constipation, diarrhea, headache, dizziness, photosensitivity reactions, orthostatic hypotension, paraesthesia, impotence and yellow vision. Hypersensitivity reactions include skin rashes, fever, pulmonary oedema and pneumonitis. Cholestatic jaundice, pancreatitis and blood dyscrasias have been reported