BENDROFLUAZIDE 5MG TABLET

Indications

• Hypertension
• Heart failure
• Edema associated with renal disorders
• Cirrhosis of the liver

Dosage

Children: Refer to the BNF for Children for specific dosing information for paediatric patients.

Adults: The usual adult dose for hypertension is 5-10 mg once daily, which may be adjusted based on patient response and blood pressure control.

Mechanism of action

Bendrofluazide inhibits active chloride reabsorption at the early distal tubule via the Na-Cl cotransporter. This mechanism results in increased excretion of sodium, chloride, and water. Additionally, it may cause vasodilation through its action on carbonic anhydrases and large-conductance calcium-activated potassium channels in smooth muscle. The diuretic effect is enhanced by the inhibition of sodium and chloride reabsorption, which also affects potassium and uric acid levels.

Pharmacodynamics

As a thiazide diuretic, bendrofluazide increases urine output by inhibiting Na+/Cl- reabsorption in the distal convoluted tubules of the kidneys. This leads to a reduction in blood volume and blood pressure. Although primarily used for hypertension, it also prevents complications related to high blood pressure through mechanisms that may involve vascular smooth muscle relaxation.

Pharmacokinetics

Bendrofluazide is well absorbed from the gastrointestinal tract, with peak plasma concentrations occurring within 1-2 hours after oral administration. The drug is primarily excreted unchanged in urine, with a half-life of approximately 6-15 hours. It is not extensively metabolized by the liver. It may affect electrolyte levels, leading to increased potassium loss and elevated serum uric acid levels.

Adverse effects

• Hypokalemia
• Hyponatremia
• Hyperuricemia
• Dehydration
• Dizziness
• Gastrointestinal disturbances
• Allergic reactions

Interactions

• Non-steroidal anti-inflammatory drugs (NSAIDs) may reduce the diuretic effect.
• Lithium levels may increase due to decreased clearance.
• Corticosteroids may exacerbate electrolyte imbalances.
• Antidiabetic agents may have reduced effectiveness.

Precautions

• Monitor electrolytes regularly, especially potassium levels.
• Use cautiously in patients with renal impairment.
• Consider the risk of dehydration in elderly patients.
• Assess for a history of gout due to the risk of hyperuricemia.

Pregnancy

Bendroflumethiazide should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is not recommended as it may affect fetal electrolyte balance.

Breast-feeding

Bendroflumethiazide is excreted in breast milk. Caution is advised when administering to nursing mothers.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Formulations

• Tablets: 2.5 mg, 5 mg

Mechanism of action

As a diuretic, bendroflumethiazide inhibits active chloride reabsorption at the early distal tubule via the Na-Cl cotransporter, resulting in an increase in the excretion of sodium, chloride, and water. Thiazides like bendroflumethiazide also inhibit sodium ion transport across the renal tubular epithelium through binding to the thiazide sensitive sodium-chloride transporter. This results in an increase in potassium excretion via the sodium-potassium exchange mechanism. The antihypertensive mechanism of bendroflumethiazide is less well understood although it may be mediated through its action on carbonic anhydrases in the smooth muscle or through its action on the large-conductance calcium-activated potassium (KCa) channel, also found in the smooth muscle. ...BENZOTHIADIAZIDES HAVE DIRECT EFFECT ON RENAL TUBULAR TRANSPORT OF SODIUM & CHLORIDE...INDEPENDENT OF ANY EFFECT ON CARBONIC ANHYDRASE. /THIAZIDE DIURETICS/ NATURE OF CHEM INTERACTION BETWEEN THIAZIDES & SPECIFIC RENAL RECEPTORS RESPONSIBLE FOR CHLORURETIC EFFECT IS NOT KNOWN; NO CRITICAL ENZYMATIC REACTIONS HAVE BEEN IDENTIFIED. /THIAZIDE DIURETICS/ ...MAY DECR EXCRETION OF URIC ACID IN MAN, THUS INCR ITS CONCN IN PLASMA. HYPERURICEMIC EFFECT RESULTS PRIMARILY FROM INHIBITION OF TUBULAR SECRETION OF URATE. ... UNLIKE MOST OTHER NATRIURETIC AGENTS...DECR RENAL EXCRETION OF CALCIUM RELATIVE TO THAT OF SODIUM... /ENHANCE/ EXCRETION OF MAGNESIUM... /THIAZIDE DIURETICS/ THIAZIDES INHIBIT REABSORPTION OF SODIUM &...CHLORIDE IN DISTAL SEGMENT. ... AS CLASS...HAVE IMPORTANT ACTION ON EXCRETION OF POTASSIUM THAT RESULTS FROM INCR SECRETION OF CATION BY DISTAL TUBULE. ... GLOMERULAR FILTRATION RATE MAY BE REDUCED BY THIAZIDES, PARTICULARLY WITH IV ADMIN FOR EXPTL PURPOSES. /THIAZIDE DIURETICS/ For more Mechanism of Action (Complete) data for BENDROFLUMETHIAZIDE (11 total), please visit the HSDB record page.

Pharmacodynamics

Bendroflumethiazide, a thiazide diuretic, removes excess water from the body by increasing how often you urinate (pass water) and also widens the blood vessels which helps to reduce blood pressure. It inhibits Na⁺/Cl^- reabsorption from the distal convoluted tubules in the kidneys. Thiazides also cause loss of potassium and an increase in serum uric acid. Thiazides are often used to treat hypertension, but their hypotensive effects are not necessarily due to their diuretic activity. Thiazides have been shown to prevent hypertension-related morbidity and mortality although the mechanism is not fully understood. Thiazides cause vasodilation by activating calcium-activated potassium channels (large conductance) in vascular smooth muscles and inhibiting various carbonic anhydrases in vascular tissue.