Furosemide, tablets 40 mg 56 pcs

Pharmacotherapeutic group: Diuretic.

ATC code: C03CA01

Pharmacological properties

Pharmacodynamics

Furosemide is a fast-acting diuretic that is a sulfonamide derivative. Furosemide blocks the transport system of sodium, potassium, chlorine ions in the thick segment of ascending knee of Genle loop, due to which its diuretic action depends on entering the drug into renal tubules lumen (due to mechanism of anion transport). Diuretic effect of Furosemide is associated with inhibition of sodium chloride reabsorption in this part of the Genle loop. Secondary effects to the increase in sodium excretion are: increase in the amount of excreted urine (due to osmotically bound water) and increased potassium secretion in the distal part of the renal tubule. At the same time the excretion of calcium and magnesium ions increases.

If tubular secretion is decreased or if furosemide binds to albumin in the tubular lumen (e.g., in nephrotic syndrome), the effect of furosemide is reduced.

Furosemide does not decrease diuretic activity when administered as a course because furosemide interrupts the tubule-glomerular feedback in Macula densa (a tubular structure closely associated with the juxtaglomerular complex). Furosemide causes dose-dependent stimulation of the renin-angiotensin-aldosterone system.

In heart failure, furosemide rapidly reduces preload (through vein dilation), reduces pulmonary artery pressure and left ventricular filling pressure. This rapidly developing effect appears to be mediated through the effects of prostaglandins, and therefore a condition for its development is the absence of disturbances in prostaglandin synthesis, in addition to which sufficient preservation of renal function is also required to realize this effect.

Furosemide has hypotensive effect due to increase in sodium excretion, decrease in circulating blood volume and decrease in vascular smooth muscle response to vasoconstrictor stimuli (due to the natriuretic effect furosemide reduces vascular response to catecholamines which concentration is increased in patients with arterial hypertension).

After oral administration of 40 mg of Furosemide, the diuretic effect develops within 60 minutes and lasts about 3-6 hours. When increasing the dosage of Furosemide from 10 to 100 mg, a dose-dependent increase in diuresis and natriuresis is observed.

Pharmacokinetics

Intake

Furosemide is rapidly absorbed in the gastrointestinal tract. The time to reach maximum blood concentration (T_max) is 1 to 1.5 hours. Bioavailability of furosemide in healthy volunteers is approximately 50-70%. In patients, the bioavailability of furosemide may decrease up to 30%, as it may be affected by various factors, including the underlying disease.

Distribution

The volume of distribution of furosemide is 0.1-0.2 L/kg body weight. Furosemide binds to plasma proteins (more than 98%), mainly to albumin.

Metabolism/Exhaustion

Furosemide is excreted predominantly unchanged and mainly by secretion in the proximal tubules. Glucuronized metabolites of furosemide account for 10-20% of the drug excreted by the kidneys. The remaining dose is excreted through the intestine, apparently by biliary secretion. Final elimination half-life of furosemide is approximately 1-1.5 hours. Furosemide penetrates the placental barrier and is excreted in the mother’s milk. Its concentrations in the fetus and the newborn are the same as in the mother.

Peculiarities of pharmacokinetics in selected groups of patients

In renal failure elimination of furosemide is delayed and the elimination half-life is prolonged; in severe renal insufficiency, the final elimination half-life may be prolonged up to 24 hours.

In nephrotic syndrome, decreased plasma protein concentrations lead to increased concentrations of unbound furosemide (its free fraction), thereby increasing the risk of ototoxic effects. On the other hand, the diuretic effect of furosemide in these patients may be reduced due to the binding of furosemide to albumin in the tubules and decreased tubular secretion of furosemide.

In hemodialysis and peritoneal dialysis, and continuous ambulatory peritoneal dialysis, furosemide is marginally excreted.

In hepatic insufficiency, the half-life of furosemide is increased by 30-90%, mainly due to increased volume of distribution. Pharmacokinetic parameters in this category of patients may vary significantly.

In heart failure, severe arterial hypertension and in elderly patients excretion of furosemide is delayed due to decreased renal function.

Indications

• Oedematous syndrome in chronic heart failure;
• edematous syndrome in chronic renal failure;
• acute renal failure, including those in pregnancy and burns (to maintain fluid excretion)
• Oedematous syndrome in chronic renal failure.edematous syndrome in nephrotic syndrome (in nephrotic syndrome, treatment of the underlying disease is the first priority);
• edematous syndrome in liver disease (if necessary in addition to treatment with aldosterone antagonists);
• arterial hypertension.

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Active ingredient

Furosemide

Composition

Active ingredient: Furosemide 40.00 mg

Excipients:

Potato starch 56.88 mg

Lactose monohydrate 53.00 mg

Pregelatinized corn starch 7.00 mg

talt 2.40 mg

silica colloidal silica (aerosil) 0.40 mg

magnesium stearate 0.32 mg

How to take, the dosage

General recommendations

The tablets should be taken on an empty stomach, without chewing and with plenty of water.

When Furosemide is prescribed, it is recommended that it be taken in the lowest dose sufficient to have the desired therapeutic effect.

The recommended maximum daily dose for adults is 1500 mg, and in children it is 40 mg.

The duration of treatment is determined by the physician individually depending on the indications.

Special dosing recommendations

Children

In children, the recommended daily dose for oral administration is 2 mg/kg body weight (but no more than 40 mg per day).

Adults

• Oedema syndrome in liver disease

Interaction

Unrecommended combinations

• Chloral hydrate – Intravenous infusion of furosemide within 24 hours of chloral hydrate administration may result in skin hyperemia, profuse sweating, restlessness, nausea, increased blood pressure, and tachycardia. Therefore, the use of furosemide together with chloral hydrate is not recommended.
• Aminoglycosides – slowing of renal excretion of aminoglycosides when used simultaneously with furosemide and increased risk of ototoxic and nephrotoxic effects of aminoglycosides. For this reason, the use of this drug combination should be avoided unless it is necessary for vital indications, in which case correction (reduction) of maintenance doses of aminoglycosides is required.

Combinations in which caution should be exercised

• Ototoxic drugs -furosemide potentiates their ototoxicity. This medicine should only be used concomitantly with furosemide for strict medical indications because its combined use may cause permanent damage to the ear.
• Cisplatin – when used concomitantly with furosemide there is a risk of ototoxicity. In addition, the nephrotoxic effects of cisplatin may be enhanced when furosemide is used for forced diuresis during cisplatin treatment, unless furosemide is used at a low dose (e.g., 40 mg in patients with normal renal function) and in combination with appropriate hydration of the patient.
• Sucralfate – reduced absorption of furosemide when taken together orally and weakened its effect (furosemide and sucralfate must be taken at least two hours apart when taken orally).
• Lithium salts – Furosemide reduces lithium excretion and thereby increases serum lithium levels, which increases the risk of its toxic effects, including cardiotoxic and neurotoxic effects. Therefore, monitoring of serum lithium levels is required when using this combination.
• Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor antagonists – use of ACE inhibitors or angiotensin II receptor antagonists in patients
  previously treated with furosemide may lead to excessive lowering of blood pressure with worsening of renal function, and in some cases, the development of acute renal failure, so 3 days before starting treatment or increasing the dose of ACE inhibitors or angiotensin II receptor antagonists, it is recommended to cancel furosemide or reduce its dose.
• Risperidone – Care should be taken, carefully weighing the risk-benefit ratio, before deciding to use a combination of risperidone with furosemide or other strong diuretics, as increased mortality has been observed in elderly patients with dementia who received concurrent treatment with risperidone and furosemide.
• Levothyroxine – Furosemide at high doses may inhibit the binding of thyroid hormones to carrier proteins and thus lead initially to a transient increase in free thyroid hormone concentrations and then generally to a decrease in total thyroid hormone concentrations. Thyroid hormone concentrations should be monitored when using this combination.

Interactions to consider

• Nonsteroidal anti-inflammatory drugs (NSAIDs) – NSAIDs, including acetylsalicylic acid, may decrease the diuretic effect of furosemide.

In patients with hypovolemia and dehydration (including those taking Furosemide), NSAIDs may cause acute renal failure. Furosemide may increase the toxicity of salicylates.

• Phenytoin – decrease the diuretic effect of furosemide.
• Glucocorticosteroids, carbenoxolone, licorice preparations in large amounts and prolonged use of laxatives in combination with furosemide increase the risk of hypokalemia.
• Heart glycosides, drugs that cause prolongation of the QT interval – In case of development of electrolyte-water balance disorders (hypokalemia or hypomagnesemia) against furosemide use, the toxic effect of cardiac glycosides and QT prolongers (increase the risk of cardiac arrhythmias) increases.
• Hypotensive agents, diuretics or other agents capable of reducing blood pressure – when combined with furosemide, a more pronounced reduction in blood pressure is possible.
• Probenecid, methotrexate or other drugs which, like furosemide, are expressed in the renal tubules, can reduce the effects of furosemide (same renal excretion pathway); on the other hand, furosemide can lead to decreased renal excretion of these drugs. All this increases the risk of HP of both furosemide and the above medications taken concomitantly with furosemide.
• Hypoglycemic agents (both oral and insulin preparations), pressor amines (epinephrine, norepinephrine) – weakened effects when combined with furosemide.
• Theophylline, diazoxide, curare-like muscle relaxants – increased effects when combined with furosemide.
• Drugs with nephrotoxic effects – when combined with furosemide, the risk of their nephrotoxic effects increases.
• High doses of some cephalosporins (primarily excreted by the kidneys) – The risk of nephrotoxic effects of cephalosporins increases in combination with furosemide.
• Cyclosporine A – When combined with furosemide, the risk of gouty arthritis increases due to furosemide-induced hyperuricemia and impaired renal urate excretion by cyclosporine.
• Rentgen contrast agents. – patients at high risk of nephropathy after contrast agent treatment with furosemide had a higher incidence of renal dysfunction after contrast agent administration compared with patients at high risk of nephropathy after contrast agent administration who received only intravenous fluid administration (hydration) before contrast agent administration.

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Special Instructions

Symptomatic arterial hypotension leading to dizziness, fainting or loss of consciousness may occur in patients receiving furosemide, especially: in elderly patients; in patients taking other drugs that may lead to arterial hypotension; and in patients with other diseases that carry the risk of developing arterial hypotension. Caution should be exercised when treating such patients, and/or they may need to reduce the dose of furosemide.

Before starting treatment with Furosemide, the presence of severe urinary outflow disorders, including unilateral ones, should be excluded. Patients with partial urine outflow disorder require close monitoring, especially at the beginning of treatment with Furosemide.

With Furosemide treatment it is necessary to perform regular monitoring of sodium, potassium and creatinine concentration in serum; especially careful monitoring should be conducted in patients with high risk of electrolyte and fluid disturbances in cases of additional fluid and electrolyte losses (e.g., due to vomiting, diarrhea or heavy perspiration).

Before and during treatment with Furosemide, hypovolemia or dehydration as well as clinically significant electrolyte-water balance and/or acid-base balance disorders should be monitored and, if they occur, treatment with Furosemide may need to be discontinued for short periods.

When treating with Furosemide it is always advisable to eat food rich in potassium (lean meat, potatoes, bananas, tomatoes, cauliflower, spinach, dried fruits and so on). In some cases, the intake of potassium or the use of potassium-saving drugs may be indicated.

In patients with hypoproteinemia, such as that associated with nephrotic syndrome, the effectiveness of furosemide may be impaired and its ototoxicity increased. Caution is required to increase the dose.

A higher rate of death has been observed in elderly patients with dementia treated concomitantly with risperidone and furosemide compared with patients receiving either furosemide alone or risperidone alone. The pharmacophysiological mechanism of this effect has not been established. Concomitant use of risperidone with other diuretics (mainly low-dose thiazide diuretics) has not been associated with increased mortality in elderly patients with dementia. In elderly patients with dementia, furosemide and risperidone should be used with caution, carefully weighing the benefit-risk ratio. Because dehydration is a common risk factor for increased mortality, patient dehydration should be avoided when deciding to use this combination in elderly patients with dementia.

There is a possibility of worsening the course or exacerbation of systemic lupus erythematosus.

The dosing regimen of patients with ascites in cirrhosis should be chosen in hospital (impaired water-electrolyte balance can lead to hepatic coma).

Impact on driving, operating machinery

Some side effects (e.g., significant decrease in blood pressure) may impair ability to concentrate and decrease psychomotor reactions, which may be dangerous when driving vehicles or engaging in other potentially dangerous activities. This especially refers to the period of starting treatment or increasing the dose of the drug, as well as in cases of simultaneous intake of hypotensive drugs or alcohol. In such cases, it is not recommended to drive vehicles or engage in potentially dangerous activities.

Synopsis

Round flat cylindrical tablets, white or white with a yellowish tint, with a bevel and a rib.

Contraindications

Hypersensitivity to the active ingredient or any of the excipients of the drug;

• patients with an allergy to sulfonamides (sulfonamide antimicrobials or sulfonylurea derivatives), since a “cross” allergy to furosemide may develop;
• renal failure with anuria (if there is no response to furosemide administration);
• hepatic coma and precoma associated with hepatic encephalopathy;
• severe hypokalemia (see side effects);
• severe hyponatremia;
• hypovolemia (with or without a decrease in blood pressure) or dehydration;
• explicit urinary outflow disorders of any etiology, including unilateral urinary tract involvement;
• intoxication with cardiac glycosides;
• acute glomerulonephritis;
• decompensated aortic and mitral stenosis, hypertrophic obstructive cardio-
  myopathy;
• increased central venous pressure (over 10 mmHg. sts.);
• common hereditary galactose intolerance, lactase deficiency, glucose-galactose malabsorption syndrome;
• children under 3 years of age (solid dosage form);
• breastfeeding period (see “Administration during pregnancy and breastfeeding”).

With caution

• Hypotension
• in conditions where an excessive decrease in blood pressure is particularly dangerous (marked stenosis of the coronary and/or cerebral arteries);
• in acute myocardial infarction (increased risk of cardiogenic shock);
• in latent or manifest diabetes;

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• in gout;
• in hepatorenal syndrome (functional renal failure associated with liver disease);
• in hypoproteinemia (e.g., nephrotic syndrome, where there may be a reduction in the diuretic effect and an increased risk of ototoxic effects of furosemide); dosage selection in such patients should be performed with special caution;
• in partial obstruction of the urinary tract (prostatic hyperplasia, narrowing of the urethra);
• in pancreatitis;
• in a history of ventricular arrhythmias;
• in systemic lupus erythematosus;
• in concomitant use of risperidone in elderly patients with dementia (risk of increased mortality).

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Side effects

The following are the adverse reactions (ARs) that have been identified in clinical trials as well as in the use of furosemide in clinical practice.

The following criteria were used to assess the frequency of NRs: “very common” (≥ 1/10); “common” (≥ 1/100, < 1/10); “infrequent” (≥ 1/1000, < 1/100); “rare” (≥ 1/10000, < 1/1000); “very rare” (< 1/10000). NRs are grouped according to the system-organ classes of the MedDRA Medical Regulatory Dictionary, within each class NRs are listed in descending order of frequency of occurrence, within each group allocated by frequency of occurrence, NRs are categorized in decreasing order of importance.

Blood and lymphatic system disorders

Frequently:

• hemoconcentration.

Infrequent:

• thrombocytopenia.

Rarely:

• leukopenia, eosinophilia.

Very rare:

• agranulocytosis, aplastic anemia or hemolytic anemia.

Disorders of the immune system

Rarely:

• severe anaphylactic or anaphylactoid reactions up to the development of anaphylactic shock.

Frequency unknown:

• serious course or exacerbation of systemic lupus erythematosus.

Metabolic and nutritional disorders

Very common:

• disorders of water-electrolyte balance, including disorders of water-electrolyte balance, occurring with clinical symptomatology. Symptoms indicative of the development of electrolyte-water balance disorders may include headache, seizures, tetany, muscle weakness, heart rhythm disorders, and dyspeptic disorders. These disorders may develop either gradually (over a long time) or rapidly (within a very short time, e.g., when high doses of Furosemide are used in patients with normal renal function). Factors contributing to the development of electrolyte balance disorders are underlying diseases (e.g., cirrhosis or heart failure), concomitant therapy with water-electrolyte changing agents, poor diet and drinking regime, vomiting, diarrhea, profuse sweating;
dehydration and hypovolemia (decreased circulating blood volume), especially in elderly patients, which may lead to hemoconcentration with increased risk of thrombosis (see below);
• increased blood creatinine concentration;
• increased serum triglyceride concentration.

Frequently:

• hyponatremia, hypochloremia, hypokalemia, increased blood cholesterol concentration;
• increased blood uric acid concentration and gout attacks.

Infrequent:

• decreased glucose tolerance. Latent diabetes mellitus may become manifest (see section “Special Indications”).

Frequency is unknown:

• Hypocalcemia, hypomagnesemia, increased blood urea concentration, metabolic alkalosis, Bartter’s pseudosyndrome when furosemide is used improperly and/or prolonged.

Nervous system disorders

Frequently:

• hepatic encephalopathy in patients with hepatocellular insufficiency (see Contraindications).

Rarely:

• paresthesias.

Frequency unknown:

• dizziness, syncope (fainting) or loss of consciousness, headache.

Hearing and labyrinth disorders

Infrequent:

• Hearing impairment, usually transient, especially in patients with renal insufficiency,
  hypoproteinemia (e.g., in nephrotic syndrome) and/or rapid intravenous furosemide administration. Cases of deafness, sometimes irreversible, have been reported after oral or intravenous furosemide.

Rarely:

• Tinnitus.

Vascular disorders

Very common (for intravenous infusion):

• decrease in blood pressure, including orthostatic hypotension (this HP mainly refers to parenteral use of furosemide).

Rarely:

• vasculitis.

Frequency unknown:

• thrombosis.

Gastrointestinal disorders

Infrequent:

• Nausea.

Rarely:

• vomiting, diarrhea.

Very rare:

• acute pancreatitis.

Liver and biliary tract disorders

Very rare:

• cholestasis, increased activity of “hepatic” transaminases.

Skin and subcutaneous tissue disorders

Infrequent:

• cutaneous itching, urticaria, rash, bullous dermatitis, erythema multiforme, pemphigoid, exfoliative dermatitis, purpura, photosensitization reactions.

Frequency unknown:

• Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalized exanthematous pustulosis, DRESS syndrome: A drug-induced rash with eosinophilia and systemic symptoms.

Muscle, skeletal and connective tissue disorders

Frequency unknown:

• cases of rhabdomyolysis have been reported, often associated with severe hypokalemia (see Contraindications).

Renal and urinary tract disorders

Frequently:

• increased urine volume.

Rarely:

• tubulointerstitial nephritis.

Frequency unknown:

• increased sodium and chloride levels in the urine;
• lost urine (in patients with partial urinary tract obstruction, see “Special Instructions”);
• nephrocalcinosis/nephrolithiasis in premature infants (see Special Indications). This NR applies only to the injectable dosage form of Furosemide because it is contraindicated in children under 3 years of age;
• renal insufficiency (see section “Interaction with other medicinal products”).

Congenital, familial and genetic disorders

Frequency is unknown:

• increased risk of arterial duct obstruction when furosemide is given to premature infants during the first weeks of life (applies to parenteral dosage form only).

General disorders and reactions at the site of administration

Rarely:

• Fever.

Because some NRs (such as changes in blood patterns, severe anaphylactic or anaphylactoid reactions, severe skin allergic reactions) can be life-threatening in patients under certain conditions, if any NRs occur, they should be reported to a physician immediately.

Overdose

If an overdose is suspected, you should always consult a physician, as certain treatment measures may be necessary in case of an overdose.

Symptoms:The clinical picture of acute or chronic overdose of the drug depends mainly on the degree and consequences of fluid and electrolyte loss. Overdose can manifest itself as hypovolemia, dehydration, hemoconcentration, cardiac rhythm and conduction disorders (including atrioventricular blockade and ventricular fibrillation). Symptoms of these disorders are a pronounced decrease in blood pressure, progressing up to the development of shock, acute renal failure, thrombosis, delirium, flaccid paralysis, apathy and confusion.

Treatment:There is no specific antidote. If little time has elapsed after ingestion, to reduce absorption of furosemide from the gastrointestinal tract, attempt to induce vomiting or gastric lavage and then take activated charcoal orally.

The treatment is aimed at correction of clinically significant disorders of electrolyte-water balance and acid-base status with monitoring of serum electrolytes, acid-base status, hematocrit, and the prevention or therapy of possible severe complications arising from these disorders.

Pregnancy use

Pregnancy

Furosemide penetrates the placental barrier, therefore the drug should not be prescribed during pregnancy. Furosemide should only be taken if the anticipated benefit to the mother exceeds the potential risk to the fetus, in which case the fetus should be closely monitored.

Period of breastfeeding

The drug is contraindicated during lactation because furosemide may be excreted with breast milk and suppress lactation. Women taking furosemide should stop breastfeeding.