| Indication |
For the treatment of edema associated with congestive heart failure, hepatic and renal disease including the nephrotic syndrome. |
| 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. It is said to be a more predictable
diuretic, meaning that the predictable absorption is reflected in a more
predictable effect. Bumetanide is 40 times more potent than furosemide
(for patients with normal renal function). |
| 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. |
| Absorption |
Bumetanide is completely absorbed (80%), and the absorption is not
altered when taken with food. Bioavailability is almost complete. |
| Volume of distribution |
Not Available |
| Protein binding |
97% |
| Metabolism |
45% is secreted unchanged. Urinary and biliary metabolites are formed by oxidation of the N-butyl side chain. |
| Route of elimination |
Oral administration of carbon-14 labeled Bumex to human volunteers
revealed that 81% of the administered radioactivity was excreted in the
urine, 45% of it as unchanged drug. Biliary excretion of Bumex amounted
to only 2% of the administered dose. |
| Half life |
60-90 minutes |
| Clearance |
- 0.2 – 1.1 mL/min/kg [preterm and full-term neonates with respiratory disorders]
- 2.17 mL/min/kg [neonates receiving bumetanide for volume overload]
- 1.8 +/- 0.3 mL/min/kg [geriatric subjects]
- 2.9 +/- 0.2 mL/min/kg [younger subjects]
|
| 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. |
