Bumetanide

Absorption

Bumetanide is completely absorbed (80%), and the absorption is not altered when taken with food. Bioavailability is almost complete.

Toxicity

Overdosage can lead to acute profound water loss, volume and electrolyte depletion, dehydration, reduction of blood volume and circulatory collapse with a possibility of vascular thrombosis and embolism. Electrolyte depletion may be manifested by weakness, dizziness, mental confusion, anorexia, lethargy, vomiting and cramps. Treatment consists of replacement of fluid and electrolyte losses by careful monitoring of the urine and electrolyte output and serum electrolyte levels.

Chemical properties

Crystalline Solid

Originator

Burinex,Leo,UK,1973

The Uses of Bumetanide

Bumetanide is a diuretic.

The Uses of Bumetanide

antineoplastic, alkylating agent

The Uses of Bumetanide

Bumetanide is used for relieving edema associated with cardiac insufficiency, for liver and kidney diseases including nephrotic syndrome, for ascites, and hypertension.

What are the applications of Application

Bumetanide (Ro 10-6338) is a specific inhibitor of Na+-K+-2Cl- cotransporter NKCC1

Background

Bumetanide is a sulfamyl diuretic.

Indications

For the treatment of edema associated with congestive heart failure, hepatic and renal disease including the nephrotic syndrome.

Definition

ChEBI: A member of the class of benzoic acids that is 4-phenoxybenzoic acid in which the hydrogens ortho to the phenoxy group are substituted by butylamino and sulfamoyl groups. Bumetanide is a diuretic, and is used for treatment of oedema associated with congestive heart failure, hepatic and renal disease.

Manufacturing Process

Preparation of 3-Nitro-4-Phenoxy-5-Sulfamylbenzoic Acid: A mixture of 4- chloro-3-nitro-5-sulfamylbenzoic acid (140 grams), phenol (100 grams), sodium hydrogencarbonate (170 grams), and water (1.000 ml) was heated to 85°C while stirring and kept at this temperature for 16 hours. After cooling to 4°C, the precipitated sodium salt of 3-nitro-4-phenoxy-5-sulfamylbenzoic acid was filtered off and washed with ice water. The sodium salt was dissolved in boiling water (3,000 ml), and the 3-nitro-4-phenoxy-5-sulfamylbenzoic acid was precipitated by addition of 4N hydrochloric acid. After cooling, the acid was isolated by suction and dried. The melting point was 255°-256°C.
Preparation of 3-Amino-4-Phenoxy-5-Sulfamylbenzoic Acid: A suspension of 3- nitro-4-phenoxy-5-sulfamylbenzoic acid (20 grams) in water (100 ml) was adjusted to pH 8 by addition of 1N lithium hydroxide. The resulting solution was hydrogenated at room temperature and 1.1 atmospheres hydrogen pressure after addition of Pd on carbon catalyst (0.6 grams catalyst containing 10% Pd). After the hydrogen uptake had become negligible, the catalyst was removed by filtration, and the 3-amino-4-phenoxy-5-sulfamylbenzoic acid was precipitated from the filtrate by addition of 4N hydrochloric acid to pH 2.5. After recrystallization from aqueous ethanol and drying, the melting point was 255°-256°C.
Preparation of 3-n-Butylamino-4-Phenoxy-5-Sulfamylbenzoic Acid: To a suspension of 3-amino-4-phenoxy-5-sulfamyibenzoic acid (10 grams) in nbutanol (200 ml), concentrated sulfuric acid (2 ml) was added while stirring. The reaction mixture was heated under reflux under conditions in which the water formed during the reaction could be removed. When, after dilution with n-butanol, the NMR-spectrum of a sample of the reaction mixture showed at the two doublets of the aromatic protons in ring A that the butyl-3-amino-4- phenoxy-5-sulfamylbenzoate formed as an intermediate was more than 90% converted to the corresponding 3-n-butylaminobenzoate, 2 N sodium hydroxide (200 ml) was added and the boiling was continued for 45 minutes. After the saponification, the reaction mixture was neutralized to pH 8 by addition of concentrated hydrochloric acid.
By cooling, the sodium salt of 3-n-butylamino-4-phenoxy-5-sulfamylbenzoic acid precipitated. It was filtered off and recrystallized from water (100 ml). The sodium salt, crystallizing with 3 molecules of water, was then dissolved in boiling water (200 ml), 1N hydrochloric acid was added to pH 2.5, and after cooling the precipitated 3-n-butylamino-4-phenoxy-5-sulfamylbenzoic acid was collected by filtration. After recrystallization from aqueous ethanol and drying, the pure compounds were obtained with melting point 230°-231°C.

brand name

Bumex (Roche).

Therapeutic Function

Diuretic

Biological Activity

Loop diuretic that inhibits the Na + /2Cl - /K + (NKCC) cotransporter. More potent than furosemide (5-(Aminosulfonyl)-4-chloro-2-([2-furanylmethyl]amino)benzoic acid ).

Biochem/physiol Actions

Inhibitor of Na+/K+/Cl- cotransporter.

Pharmacokinetics

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.

Clinical Use

A diuretic structurally related to furosemide is bumetanide. This compound also functions as a high-ceiling diuretic in the ascending limb of the loop of Henle. It has a duration of action of approximately 4 hours. The uses of this compound are similar to those described for furosemide. The dose of bumetanide is 0.5 to 2 mg/day given as a single dose.

Synthesis

Bumetanide, 3-butylamino-4-phenoxy-5-sulfamoylbenzoic acid (21.4.6), is synthesized from 4-chlorobenzoic acid. In the first stage of synthesis, it undergoes sulfonylchlorination by chlorosulfonic acid, forming 4-chloro-3-chlorosulfonylbenzoic acid (21.4.1), which is further nitrated with nitric acid to 4-chloro-3-chlorosulfonyl-5-nitrobenzoic acid (21.4.2). Reacting this with ammonia gives 5-aminosulfonyl-4-chloro-3-nitrobenzoic acid (21.4.3), which when reacted with sodium phenolate is transformed into 5-amino-sulfonyl-3-nitro-5-phenoxybenzoid acid (21.4.4). Reduction of the nitro group in this product by hydrogen using a palladium on carbon catalyst gives 3-amino-5-aminosulfonyl- 5-phenoxybenzoic acid (21.4.5). Finally, reacting this with butyl alcohol in the presence of sulfuric acid gives the desired bumetanide (21.4.6).

Drug interactions

Potentially hazardous interactions with other drugs
Analgesics: increased risk of nephrotoxicity with NSAIDs; antagonism of diuretic effect with NSAIDs.
Anti-arrhythmics: risk of cardiac toxicity with anti-arrhythmics if hypokalaemia occurs; effects of lidocaine and mexiletine antagonised.
Antibacterials: increased risk of ototoxicity with aminoglycosides, polymyxins and vancomycin; avoid with lymecycline.
Antidepressants: increased risk of hypokalaemia with reboxetine; enhanced hypotensive effect with MAOIs; increased risk of postural hypotension with tricyclics.
Antiepileptics: increased risk of hyponatraemia with carbamazepine.
Antifungals: increased risk of hypokalaemia with amphotericin.
Antihypertensives: enhanced hypotensive effect; increased risk of first dose hypotensive effect with alpha-blockers; increased risk of ventricular arrhythmias with sotalol if hypokalaemia occurs.
Antipsychotics: increased risk of ventricular arrhythmias with amisulpride or pimozide if hypokalaemia occurs - avoid with pimozide; enhanced hypotensive effect with phenothiazines.
Atomoxetine: increased risk of ventricular arrhythmias if hypokalaemia occurs.
Cardiac glycosides: increased toxicity if hypokalaemia occurs.
Cytotoxics: increased risk of ventricular arrhythmias due to hypokalaemia with arsenic trioxide; increased risk of nephrotoxicity and ototoxicity with platinum compounds.
Lithium: risk of toxicity.

Metabolism

45% is secreted unchanged. Urinary and biliary metabolites are formed by oxidation of the N-butyl side chain.

Metabolism

About 80% of a dose of bumetanide is excreted in the urine, about 50% as unchanged drug, and 10-20% in the faeces. No active metabolites are known. In patients with chronic renal failure the liver takes more importance as an excretory pathway although the duration of action is not markedly prolonged.

storage

Store at RT