BETANID

Indications

• Oedema in heart failure
• Oedema in renal disease
• Oedema in hepatic disease
• Pulmonary oedema

Dosage

Adults: By mouth, the usual starting dose is 1 mg to 2 mg once daily, which may be adjusted based on the patient's response and severity of edema. In cases of severe edema, doses may be increased, but monitoring of electroly

Mechanism of action

Bumetanide exerts its diuretic effects by inhibiting the Na+-K+-2Cl- cotransporter located in the thick ascending limb of the loop of Henle in the nephron. This action disrupts the reabsorption of sodium, chloride, and potassium, resulting in increased diuresis and subsequent reduction in blood volume, which is beneficial in conditions characterized by fluid overload.

Pharmacodynamics

The pharmacodynamic effects of bumetanide include significant diuresis, electrolyte imbalances (notably hypokalemia), and potential metabolic alkalosis. The drug's potency is higher than that of thiazide diuretics, offering a rapid onset of action and a more substantial diuretic effect. However, it also has a higher potential for side effects such as dehydration and electrolyte disturbances due to its mechanism of action.

Pharmacokinetics

Bumetanide is rapidly absorbed following oral administration, with peak plasma concentrations typically achieved within 1 to 2 hours. It is extensively bound to plasma proteins (approximately 95%), which influences its distribution and elimination. The drug is primarily excreted via the kidneys, and its elimination half-life ranges from 1 to 2 hours in patients with normal renal function, extending in those with renal impairment. Monitoring of renal function and electrolytes is essential during treatment to mitigate the risk of adverse effects.

Contra-indications

• Hypersensitivity to bumetanide or any of its excipients
• Severe electrolyte depletion
• Anuria

Adverse effects

• Dehydration
• Hypotension
• Hyperglycaemia
• Hyperuricaemia
• Hypokalaemia
• Dizziness
• Fatigue
• Headache
• Muscle spasms
• Nausea
• Tinnitus
• Hearing impairment
• Gastrointestinal discomfort
• Gynaecomastia
• Musculoskeletal pain
• Skin reactions
• Photosensitivity
• Severe cutaneous adverse reactions (SCARs)
• Blood disorders (e.g., thrombocytopenia, leucopenia)

Interactions

• Other diuretics may enhance the risk of electrolyte imbalance
• Corticosteroids may potentiate the electrolyte-depleting effect
• Non-steroidal anti-inflammatory drugs (NSAIDs) may reduce the diuretic effect
• Cardiac glycosides: hypokalaemia may increase the risk of toxicity
• Antibiotics like aminoglycosides may increase the risk of ototoxicity

Precautions

• Monitor electrolytes during treatment
• Correct any hypovolaemia or electrolyte imbalances before initiation
• Use with caution in hepatic impairment as hypokalaemia may precipitate encephalopathy
• Risk of acute urinary retention, especially in children
• Caution in patients with gout

Pregnancy

Bumetanide should not be used to treat gestational hypertension due to the risk of maternal hypovolaemia.

Breast-feeding

No information available. May inhibit lactation.

Storage

Store below 25 degrees Celsius. Protect from light and moisture.

Formulations

• Bumetanide 1 mg tablets
• Bumetanide 5 mg tablets
• Oral suspension
• Oral solution

Mechanism of action

Bumetanide interferes with renal cAMP and/or inhibits the sodium-potassium ATPase pump. Bumetanide appears to block the active reabsorption of chloride and possibly sodium in the ascending loop of Henle, altering electrolyte transfer in the proximal tubule. This results in excretion of sodium, chloride, and water and, hence, diuresis.

Pharmacodynamics

Bumetanide is a loop diuretic of the sulfamyl category to treat heart failure. It is often used in patients in whom high doses of furosemide are ineffective. There is however no reason not to use bumetanide as a first choice drug. The main difference between the two substances is in bioavailability. Bumetanide has more predictable pharmacokinetic properties as well as clinical effect. In patients with normal renal function, bumetanide is 40 times more effective than furosemide.