BUMETANIDE: 2,144 Adverse Event Reports & Safety Profile

DESCRIPTION Bumetanide is a loop diuretic, available as scored tablets. Chemically, bumetanide is 3-(butylamino)-4-phenoxy-5-sulfamoylbenzoic acid. It is a practically white powder having a calculated molecular weight of 364.42, and the following structural formula: Each bumetanide tablet intended for oral administration contains 0.5 mg, 1 mg or 2 mg of bumetanide. In addition, each tablet contains the following inactive ingredients: colloidal silicon dioxide, corn starch, lactose monohydrate, magnesium stearate, povidone and talc. In addition, each 0.5 mg tablet contains D&C Yellow No. 10 aluminum lake, FD&C Blue No. 1 aluminum lake and ferric oxide black; each 1 mg tablet contains D&C Yellow No. 10 aluminum lake and ferric oxide red; each 2 mg tablet contains mg D&C Yellow No. 10 aluminum lake and ferric oxide red. Bumetanide tablet meets USP Dissolution Test 2. figure 1

INDICATIONS AND USAGE Bumetanide tablets USP are indicated for the treatment of edema associated with congestive heart failure, hepatic and renal disease, including the nephrotic syndrome. Almost equal diuretic response occurs after oral and parenteral administration of bumetanide. Therefore, if impaired gastrointestinal absorption is suspected or oral administration is not practical, bumetanide should be given by the intramuscular or intravenous route. Successful treatment with bumetanide tablets USP following instances of allergic reactions to furosemide suggests a lack of cross-sensitivity.

Contraindications

Bumetanide is contraindicated in anuria. Although bumetanide tablets can be used to induce diuresis in renal insufficiency, any marked increase in blood urea nitrogen or creatinine, or the development of oliguria during therapy of patients with progressive renal disease, is an indication for discontinuation of treatment with bumetanide tablets. Bumetanide is also contraindicated in patients in hepatic coma or in states of severe electrolyte depletion until the condition is improved or corrected. Bumetanide is contraindicated in patients hypersensitive to this drug.

AND ADMINISTRATION ENBUMYST is for nasal route only. ( 2 ) Individualize dosage based on patient response. The recommended total daily dosage of ENBUMYST is 0.5 mg to 2 mg administered once daily. ( 2.1 ) ENBUMYST is not intended for chronic use; replace with oral diuretics as soon as practical. ( 2.1 )

2.1 Recommended Dosage Each unit-dose nasal spray contains 0.5 mg of bumetanide. The usual total daily dosage of ENBUMYST is 0.5 mg to 2 mg once daily. The number of nasal spray devices needed for a single dose depends upon the prescribed dose. Individualize dosage based on patient response up to a maximum dose of 2 mg/day. ENBUMYST is not intended for chronic use and should be replaced with oral diuretics as soon as practical. ENBUMYST can be substituted at approximately a 1:40 ratio to oral furosemide and a 1:20 ratio to intravenous furosemide.

2.2 Administration Instructions ENBUMYST is for nasal use only. Each ENBUMYST unit is for single use and delivers 0.5 mg bumetanide upon actuation. Do not prime or attempt to reuse ENBUMYST for more than one administration. Administer ENBUMYST directly into the nose and not against the wall of the nose. If prescribed dose requires more than one nasal spray, alternate between right and left nostrils. Refer patients and caregivers to the Instructions for Use for detailed administration instructions.

CONTRAINDICATIONS Bumetanide tablets are contraindicated in anuria. Although bumetanide tablets can be used to induce diuresis in renal insufficiency, any marked increase in blood urea nitrogen or creatinine, or the development of oliguria during therapy of patients with progressive renal disease, is an indication for discontinuation of treatment with bumetanide tablets. Bumetanide tablets are also contraindicated in patients in hepatic coma or in states of severe electrolyte depletion until the condition is improved or corrected. Bumetanide tablets are contraindicated in patients hypersensitive to this drug.

REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: Fluid, electrolyte, and metabolic abnormalities [see Warnings and Precautions (5.1) ]

Worsening Renal

Function [see Warnings and Precautions (5.2) ] Ototoxicity [see Warnings and Precautions (5.3) ]

Potential Altered

Absorption in Patients with Nasal Mucosal or Structural Abnormalities [see Warnings and Precautions (5.4) ] Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of ENBUMYST is supported by clinical trials and postmarketing reports of oral bumetanide, as well as open-label, single- and repeat-dose studies of ENBUMYST in healthy subjects.

Adverse

Reactions in Two Clinical Pharmacology Studies with ENBUMYST in Adult Subjects In open-label studies of ENBUMYST in healthy subjects (n = 84), the most common adverse reaction that occurred with ENBUMYST was hypovolemia (4.8%) [see Warnings and Precautions (5.1) ] . Headache occurred in 3% of subjects. There were no adverse reactions specifically associated with the nasal route of administration such as nasal irritation or pain. There was a single case of nasal dryness.

Adverse

Reactions in Studies with Oral Bumetanide The following adverse reactions were identified in clinical studies or postmarketing reports with the use of oral bumetanide. Because some of these reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. The most frequent clinical adverse reactions considered probably or possibly related to oral bumetanide are muscle cramps (seen in 1.1% of treated patients), dizziness (1.1%), hypotension (0.8%), headache (0.6%), nausea (0.6%) and encephalopathy (in patients with pre-existing liver disease) (0.6%). One or more of these adverse reactions have been reported in approximately 4.1% of patients treated with bumetanide. The following additional adverse reactions have been reported with bumetanide. Blood and Lymphatic System Disorders: Deviations in hemoglobin, prothrombin time, hematocrit, WBC and differential counts, thrombocytopenia Cardiac Disorders: Chest pain, electrocardiogram changes Ear and Labyrinth Disorders: Ear discomfort, impaired hearing, vertigo Gastrointestinal Disorders: Abdominal pain, diarrhea, dry mouth, GI upset, vomiting General Disorders and Administration Site Conditions: Fatigue, weakness Investigations: Changes in LDH, total serum bilirubin, serum proteins, SGOT, SGPT, alkaline phosphatase, cholesterol, creatinine clearance, urinary glucose, and urinary protein Metabolism and Nutrition Disorders: Dehydration Musculoskeletal and Connective Tissue Disorders: Arthritic pain, musculoskeletal pain Nervous System Disorders: Asterixis Renal and Urinary Disorders: Renal failure Reproductive System and Breast Disorders: Erectile dysfunction, nipple tenderness, premature ejaculation Respiratory, Thoracic and Mediastinal Disorders: Hyperventilation Skin and Subcutaneous Tissue Disorders: Pruritus, rash, Stevens-Johnson syndrome, sweating, toxic epidermal necrolysis Most common adverse reactions (incidence > 0.5%) are hypovolemia, headache, muscle cramps, dizziness, hypotension, nausea and encephalopathy (in patients with pre-existing liver disease). ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Corstasis Therapeutics at 1-877-300-5339 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

WARNINGS Click here to enter Warnings Volume and Electrolyte Depletion The dose of bumetanide should be adjusted to the patient's need. Excessive doses or too frequent administration can lead to profound water loss, electrolyte depletion, dehydration, reduction in blood volume and circulatory collapse with the possibility of vascular thrombosis and embolism, particularly in elderly patients.

Hypokalemia

Hypokalemia can occur as a consequence of bumetanide administration. Prevention of hypokalemia requires particular attention in the following conditions: patients receiving digitalis and diuretics for congestive heart failure, hepatic cirrhosis and ascites, states of aldosterone excess with normal renal function, potassium-losing nephropathy, certain diarrheal states, or other states where hypokalemia is thought to represent particular added risks to the patient, i.e., history of ventricular arrhythmias. In patients with hepatic cirrhosis and ascites, sudden alterations of electrolyte balance may precipitate hepatic encephalopathy and coma. Treatment in such patients is best initiated in the hospital with small doses and careful monitoring of the patient's clinical status and electrolyte balance. Supplemental potassium and/or spironolactone may prevent hypokalemia and metabolic alkalosis in these patients. Ototoxicity In cats, dogs and guinea pigs, bumetanide has been shown to produce ototoxicity. In these test animals bumetanide was 5 to 6 times more potent than furosemide and, since the diuretic potency of bumetanide is about 40 to 60 times furosemide, it is anticipated that blood levels necessary to produce ototoxicity will rarely be achieved. The potential exists, however, and must be considered a risk of intravenous therapy, especially at high doses, repeated frequently in the face of renal excretory function impairment Potentiation of aminoglycoside ototoxicity has not been tested for bumetanide. Like other members of this class of diuretics, bumetanide probably shares this risk. Allergy to Sulfonamides Patients allergic to sulfonamides may show hypersensitivity to bumetanide.

Thrombocytopenia

Since there have been rare spontaneous reports of thrombocytopenia from post marketing experience, patients should be observed regularly for possible occurrence of thrombocytopenia.

PRECAUTIONS General Serum potassium should be measured periodically and potassium supplements or potassium sparing diuretics added if necessary. Periodic determinations of other electrolytes are advised in patients treated with high doses or for prolonged periods, particularly in those on low-salt diets. Hyperuricemia may occur; it has been asymptomatic in cases reported to date. Reversible elevations of the BUN and creatinine may also occur, especially in association with dehydration and particularly in patients with renal insufficiency. Bumetanide tablets may increase urinary calcium excretion with resultant hypocalcemia. Diuretics have been shown to increase the urinary excretion of magnesium; this may result in hypomagnesemia.

Laboratory Tests

Studies in normal subjects receiving bumetanide tablets revealed no adverse effects on glucose tolerance, plasma insulin, glucagon and growth hormone levels, but the possibility of an effect on glucose metabolism exists. Periodic determinations of blood sugar should be done, particularly in patients with diabetes or suspected latent diabetes. Patients under treatment should be observed regularly for possible occurrence of blood dyscrasias, liver damage or idiosyncratic reactions, which have been reported occasionally in foreign marketing experience. The relationship of these occurrences to bumetanide tablets use is not certain.

Drug Interactions

Drugs with Ototoxic Potential (see WARNINGS) Especially in the presence of impaired renal function, the use of parenterally administered bumetanide in patients to whom aminoglycoside antibiotics are also being given should be avoided, except in life-threatening conditions. Drugs with Nephrotoxic Potential There has been no experience with the concurrent use of bumetanide tablets with drugs known to have a nephrotoxic potential. Therefore, the simultaneous administration of these drugs should be avoided.

Lithium

Lithium should generally not be given with diuretics (such as bumetanide tablets) because they reduce its renal clearance and add a high risk of lithium toxicity.

Probenecid

Pretreatment with probenecid reduces both the natriuresis and hyperreninemia produced by bumetanide tablets. This antagonistic effect of probenecid on bumetanide tablets natriuresis is not due to a direct action on sodium excretion but is probably secondary to its inhibitory effect on renal tubular secretion of bumetanide. Thus, probenecid should not be administered concurrently with bumetanide tablets.

Indomethacin

Indomethacin blunts the increases in urine volume and sodium excretion seen during bumetanide tablets treatment and inhibits the bumetanide-induced increase in plasma renin activity. Concurrent therapy with bumetanide tablets are thus not recommended.

Antihypertensives

Bumetanide tablets may potentiate the effect of various antihypertensive drugs, necessitating a reduction in the dosage of these drugs.

Digoxin

Interaction studies in humans have shown no effect on digoxin blood levels.

Anticoagulants

Interaction studies in humans have shown bumetanide tablets to have no effect on warfarin metabolism or on plasma prothrombin activity. Carcinogenesis, Mutagenesis and Impairment of Fertility Bumetanide tablets were devoid of mutagenic activity in various strains of Salmonella typhimurium when tested in the presence or absence of an in vitro metabolic activation system.

An

18-month study showed an increase in mammary adenomas of questionable significance in female rats receiving oral doses of 60 mg/kg/day (2000 times a 2-mg human dose). A repeat study at the same doses failed to duplicate this finding. Reproduction studies were performed to evaluate general reproductive performance and fertility in rats at oral dose levels of 10, 30, 60 or 100 mg/kg/day. The pregnancy rate was slightly decreased in the treated animals; however, the differences were small and not statistically significant.

Pregnancy Teratogenic Effects

Bumetanide tablets are neither teratogenic nor embryocidal in mice when given in doses up to 3400 times the maximum human therapeutic dose. Bumetanide tablets have been shown to be nonteratogenic, but it has a slight embryocidal effect in rats when given in doses of 3400 times the maximum human therapeutic dose and in rabbits at doses of 3.4 times the maximum human therapeutic dose. In one study, moderate growth retardation and increased incidence of delayed ossification of sternebrae were observed in rats at oral doses of 100 mg/kg/day, 3400 times the maximum human therapeutic dose. These effects were associated with maternal weight reductions noted during dosing. No such adverse effects were observed at 30 mg/kg/day (1000 times the maximum human therapeutic dose). No fetotoxicity was observed at 1000 to 2000 times the human therapeutic dose. In rabbits, a dose-related decrease in litter size and an increase in resorption rate were noted at oral doses of 0.1 mg/kg/day and 0.3 mg/kg/day (3.4 and 10 times the maximum human therapeutic dose). A slightly increased incidence of delayed ossification of sternebrae occurred at 0.3 mg/kg/day; however, no such adverse effects were observed at the dose of 0.03 mg/kg/day. The sensitivity of the rabbit to bumetanide tablets parallels the marked pharmacologic and toxicologic effects of the drug in this species. Bumetanide tablets were not teratogenic in the hamster at an oral dose of 0.5 mg/kg/day (17 times the maximum human therapeutic dose). Bumetanide was not teratogenic when given intravenously to mice and rats at doses up to 140 times the maximum human therapeutic dose. There are no adequate and well-controlled studies in pregnant women. A small investigational experience in the United States and marketing experience in other countries to date have not indicated any evidence of adverse effects on the fetus, but these data do not rule out the possibility of harmful effects. Bumetanide tablets should be given to a pregnant woman only if the potential benefit justifies the potential risk to the fetus.

Nursing

Mothers It is not known whether this drug is excreted in human milk. As a general rule, nursing should not be undertaken while the patient is on bumetanide tablets since it may be excreted in human milk.

Pediatric Use

Safety and effectiveness in pediatric patients below the age of 18 have not been established. In vitro studies using pooled sera from critically ill neonates have shown bumetanide to be a potent displacer of bilirubin (see CLINICAL PHARMACOLOGY: Pediatric Pharmacology) . The administration of bumetanide could present a particular concern if given to critically ill or jaundiced neonates at risk for kernicterus.

Geriatric Use

Clinical studies of bumetanide tablets did not include sufficient numbers of subjects aged 65 and over to determine whether they responded differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy. This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

Drug Interactions Drugs with Ototoxic Potential ( See WARNINGS ) Especially in the presence of impaired renal function, the use of parenterally administered bumetanide in patients to whom aminoglycoside antibiotics are also being given should be avoided, except in life-threatening conditions. Drugs with Nephrotoxic Potential There has been no experience with the concurrent use of bumetanide with drugs known to have a nephrotoxic potential. Therefore, the simultaneous administration of these drugs should be avoided.

Lithium

Lithium should generally not be given with diuretics (such as bumetanide) because they reduce its renal clearance and add a high risk of lithium toxicity.

Probenecid

Pretreatment with probenecid reduces both the natriuresis and hyperreninemia produced by bumetanide. This antagonistic effect of probenecid on bumetanide natriuresis is not due to a direct action on sodium excretion but is probably secondary to its inhibitory effect on renal tubular secretion of bumetanide. Thus, probenecid should not be administered concurrently with bumetanide.

Indomethacin

Indomethacin blunts the increases in urine volume and sodium excretion seen during bumetanide treatment and inhibits the bumetanide-induced increase in plasma renin activity. Concurrent therapy with bumetanide is thus not recommended.

Antihypertensives

Bumetanide may potentiate the effect of various antihypertensive drugs, necessitating a reduction in the dosage of these drugs.

Digoxin

Interaction studies in humans have shown no effect on digoxin blood levels.

Anticoagulants

Interaction studies in humans have shown bumetanide to have no effect on warfarin metabolism or on plasma prothrombin activity.

Carcinogenesis , Mutagenesis and Impairment of Fertility Bumetanide was devoid of mutagenic activity in various strains of Salmonella typhimurium when tested in the presence or absence of an in vitro metabolic activation system.

An

18-month study showed an increase in mammary adenomas of questionable significance in female rats receiving oral doses of 60 mg/kg/day (2000 times a 2-mg human dose). A repeat study at the same doses failed to duplicate this finding. Reproduction studies were performed to evaluate general reproductive performance and fertility in rats at oral dose levels of 10 mg/kg/day, 30 mg/kg/day, 60 mg/kg/day or 100 mg/kg/day. The pregnancy rate was slightly decreased in the treated animals; however, the differences were small and not statistically significant.