Furosemide

Pharmacological properties

furosemide is a fast-acting loop diuretic, which causes a relatively strong and short-term diuretic effect. furosemide blocks the na + k + 2cl-cotransporter, which is located in the basement membranes of cells of a thick segment of the ascending part of the Henle loop: the effectiveness of the saluretic effect of furosemide, therefore, depends on whether the drug enters the tubules in the gaps by the anion transport mechanism. diuretic effect develops as a result of inhibition of reabsorption of sodium chloride in this segment of the loop of Henle. as a result, fractional sodium excretion can reach 35% glomerular filtration of sodium. the secondary effects of increased sodium excretion are increased urine excretion (due to osmotically bound water) and increased distal tubular secretion of potassium. excretion of calcium and magnesium ions also increases. furosemide causes dose-dependent stimulation of the renin-angiotensin-aldosterone system. in heart failure, furosemide leads to an acute decrease in cardiac preload (by narrowing of capacitive venous vessels). this early vascular effect is prostaglandin-mediated and suggests adequate renal function with activation of the renin-angiotensin system and intact prostaglandin synthesis. in addition, due to the natriuretic effect characteristic of it, furosemide reduces vascular reactivity relative to catecholamines, increased in patients with ag.

The antihypertensive effectiveness of furosemide is explained by increased sodium excretion, reduced blood volume and a decreased response of vascular smooth muscles to stimulation with vasoconstrictors or vasoconstrictors.

The onset of the diuretic effect is observed within 15 minutes after an iv dose of the drug.

A dose-dependent increase in diuresis and natriuresis was observed in healthy volunteers who received furosemide at a dose of 10-100 mg. The duration of action in healthy volunteers is about 3 hours after iv administration of 20 mg of furosemide.

In patients, the relationship between the concentrations of unbound (free) furosemide inside the tubular organs (determined based on the rate of excretion of furosemide with urine) and the natriuretic effect is expressed in the form of a sigmoid curve with a minimum effective rate of furosemide excretion, which is about 10 μg / min. Thus, continuous iv infusion of furosemide is more effective than repeated bolus injections. Moreover, in addition to a certain bolus dose of the drug, there is no significant increase in the severity of the effect. The effect of furosemide is reduced if reduced tubular secretion or binding of the drug to albumin inside the tubules occurs.

Pharmacokinetics Furosemide is rapidly absorbed in the digestive tract. The maximum absorption time is 1–1.5 hours. Absorption of the drug indicates significant individual variability.

The bioavailability of furosemide in healthy volunteers is about 50–70% for tablets. In patients, the bioavailability of a drug is influenced by various factors, including existing diseases. For example, with nephrotic syndrome, bioavailability can be reduced by up to 30%.

Eating simultaneously with furosemide may affect the absorption of furosemide.

The volume of distribution of furosemide is 0.1-0.2 l / kg of body weight. The volume of distribution may be higher depending on the disease.

Furosemide (more than 98%) forms strong compounds with plasma proteins, especially with albumin.

Furosemide is excreted mainly in the form of an unchanged drug by secretion into the proximal tubule.

The metabolite of furosemide - glucuronide - accounts for 10-20% of the substances contained in urine. The residual dose is excreted in the feces, probably by biliary secretion.

Furosemide passes into breast milk, through the placental barrier, and slowly passes into the fetus. Furosemide is determined in the fetus or in the newborn in the same concentrations as in the mother.

Kidney disease. In renal failure, the removal of furosemide is delayed, and T_½ - extended; final t_½ may be up to 24 hours in patients with severe renal failure.

In nephrotic syndrome, reduced plasma protein concentrations lead to an increase in the concentration of unbound (free) furosemide. On the other hand, the effectiveness of furosemide in these patients is reduced due to binding to intratubular albumin and reduced tubular secretion.

Furosemide does not respond well to dialysis in patients undergoing hemodialysis, peritoneal dialysis, and chronic peritoneal dialysis on an outpatient basis.

Liver failure. With liver failure T_½ furosemide increases by 30–90%, mainly due to the larger volume of distribution. In this group of patients there is a wide variety of all pharmacokinetic parameters.

Congestive heart failure, severe hypertension, elderly patients. Due to reduced kidney function in such patients, the removal of furosemide is slowed down.

Premature and full-term babies. Depending on the level of kidney formation, furosemide excretion may be delayed. The metabolism of the drug also decreases if the ability to glucuronidation is impaired in infants. Final t_½ lasts less than 12 hours in a fetus older than 33 weeks after fertilization of the egg. In infants over the age of 2 months, the final clearance is the same as in adult patients.

Indications

Edema in chronic congestive heart failure (if treatment with diuretics is necessary).

Edema in acute congestive heart failure.

Edema in chronic renal failure.

Acute renal failure, including in pregnant women or during childbirth.

Edema in liver diseases (if necessary, to supplement treatment with aldosterone antagonists).

Hypertensive crisis (as a support agent).

Injection solution - support for forced diuresis.

Application

Tablets. The doctor sets the dosage regimen individually, depending on the severity of the water-electrolyte balance disorders, glomerular filtration rate, and the severity of the patients condition. the drug is usually used on an empty stomach.

For adults, the maximum total daily dose of Furosemide-Darnitsa should not exceed 1500 mg.

Special dosage recommendations for adults

For edema in chronic congestive heart failure, the recommended initial dose of the drug for oral administration is 40 mg / day. If necessary, you can adjust the dose depending on the therapeutic response of the patient. It is recommended to take a daily dose divided into 2 or 3 doses.

For edema in chronic renal failure, the dose should be carefully titrated to ensure a gradual initial loss of fluid. For adult patients, this means the introduction of a dose that leads to a daily decrease in body weight of about 2 kg (about 280 mmol Na⁺) The recommended initial daily dose for oral administration is 40–80 mg. If necessary, you can adjust the dose depending on the therapeutic response of the patient. The total daily dose can be assigned at a time or divided into 2 doses. For patients on hemodialysis, the total daily oral dose is 250-1500 mg.

In acute renal failure, before starting the use of furosemide, hypovolemia, hypotension, and a significant electrolyte and acid-base imbalance should be compensated. It is recommended as soon as possible to make the transition from iv administration to oral administration.

For edema with nephrotic syndrome, the recommended initial dose for oral administration is 40–80 mg / day. If necessary, you can adjust the dose depending on the therapeutic response of the patient. The total daily dose can be assigned at a time or divided into several doses.

For edema with liver diseases, Furosemide-Darnitsa is prescribed as an addition to therapy with aldosterone antagonists in cases where the use of aldosterone antagonists alone is not enough. To prevent complications such as orthostatic hypotension or electrolyte and acid-base imbalances, the dose should be carefully titrated to ensure a gradual initial loss of fluid. For adult patients, this means the appointment of a dose that leads to a daily decrease in body weight of about 0.5 kg. The recommended initial daily oral dose is 40–80 mg. If necessary, you can adjust the dose depending on the therapeutic response of the patient. The daily dose can be prescribed once or divided into several doses.

The drug in this dosage form is prescribed for children with a body weight of 10 kg. For children, the recommended oral dose of furosemide is 2 mg / kg body weight, but the maximum daily dose should not exceed 40 mg.

Rr for injections. The regimen of use is determined by the doctor individually, depending on the severity of violations of the water-electrolyte balance, the value of glomerular filtration, the severity of the patients condition. During the use of the drug, the indicators of the water-electrolyte balance should be adjusted taking into account diuresis and the dynamics of the general condition of the patient.

Furosemide is prescribed iv only if the ingestion is impractical or ineffective (for example, with malabsorption in the intestine) or if necessary, a quick effect. When using iv therapy, it is recommended that as soon as possible the transition to the administration of a medicinal product for oral use.

In order to achieve optimal efficiency and inhibit counter regulation in general, continuous furosemide infusion is preferred over repeated bolus injections.

In cases where continuous infusion of furosemide is impractical for further treatment after the administration of one or more bolus doses, a further treatment regimen is preferred with the appointment of low doses that are administered at short time intervals (about 4 hours), compared with high bolus doses that are introduced at large intervals.

For adults, the recommended maximum daily dose of furosemide is 1500 mg.

For children, the recommended dose of furosemide for parenteral administration is 1 mg / kg body weight, but the maximum daily dose should not exceed 20 mg.

Special dosage recommendations. Adult dosage is generally based on the use of the recommendations below.

Edema in chronic congestive heart failure. The recommended initial dose of the drug is 20-50 mg / day. If necessary, you can adjust the dose in accordance with the therapeutic response of the patient. It is recommended to take a daily dose distributed in 2 or 3 doses.

Edema in acute congestive heart failure. The recommended initial dose of the drug is 20-40 mg / day and is prescribed as a bolus injection. If necessary, you can adjust the dose based on the therapeutic response of the patient.

Edema in chronic renal failure. The natriuretic effect of furosemide depends on a certain number of factors, including the severity of renal failure and sodium balance. Thus, it is impossible to accurately predict the effectiveness of the dose. Patients with chronic renal failure should carefully titrate the dose to ensure a gradual initial fluid loss. For adult patients, this means the use of a dose that leads to a daily decrease in body weight of about 2 kg (about 280 mmol Na⁺).

In the case of iv administration, the dose of furosemide can be determined as follows: treatment begins with the introduction of a continuous iv infusion of 0.1 mg for 1 min, then the infusion rate increases every half hour depending on the patients response.

In acute renal failure, before using furosemide, hypovolemia, hypotension, and significant electrolyte and acid-base imbalances should be compensated.

It is recommended that as soon as possible switch from iv administration to oral administration.

The recommended starting dose is 40 mg and is given as an iv injection. If the administration of this dose does not lead to the desired increase in fluid excretion, furosemide can be prescribed as a continuous iv infusion, starting with the introduction of 50-100 mg of the drug for 1 hour.

Edema with liver disease. Furosemide is prescribed as an adjunct to therapy with aldosterone antagonists in those cases where the use of only aldosterone antagonists is insufficient. To prevent complications, such as orthostatic hypotension or electrolyte and acid-base imbalance, the dose should be carefully titrated to ensure a gradual initial loss of fluid. For adult patients, this means the introduction of a dose that leads to a daily decrease in body weight of about 0.5 kg. If iv administration is absolutely necessary, the initial single dose is 20–40 mg.

Hypertensive crisis. The recommended starting dose of 20–40 mg is given as an iv bolus injection. If necessary, you can adjust the dose depending on the therapeutic response of the patient.

Support for forced diuresis in case of poisoning. Furosemide is prescribed iv in addition to the introduction of infusion of electrolyte solutions. The dose depends on the therapeutic response to furosemide. Loss of fluid and electrolytes should be adjusted during initiation and during treatment. In case of poisoning with acid or alkaline substances, the elimination of fluid can be accelerated by alkalization or oxidation of urine, respectively.

The recommended starting dose is 20–40 mg and is given iv.

Special recommendations for use

IV injection / infusion: in the case of IV injection, furosemide should be prescribed as a slow injection or infusion at a rate of not more than 4 mg per 1 minute. Patients with severe hepatic impairment (creatinine in plasma 5 mg / dl) are recommended to infuse at a rate of not more than 2.5 mg per 1 min.

Intramuscular injection: the administration of a drug in the form of an intravenous injection should be limited only to exceptional cases when oral and / or intravenous administration is not practical. It should be noted that the method of administering the drug in the form of an intramuscular injection is not indicated for the treatment of acute conditions, such as pulmonary edema.

The infusion of the drug Furosemide-Darnitsa should not be carried out together with other drugs!

Furosemide-Darnitsa is a solution with a pH level of 8.8–9.8, which does not have a buffer capacity. Thus, the active component may precipitate at pH 7. In case of dilution of this solution, attention should be paid to ensuring the pH of the dilute solution ranging from slightly alkaline to neutral.

0.9% sodium chloride solution can be used as a solvent. It is recommended to use diluted solutions as soon as possible.

Contraindications

Hypersensitivity to furosemide or other components that make up the drug. in patients allergic to sulfonamides (e.g. sulfonamide antibiotics or sulfonylurea), cross-sensitivity to furosemide may occur.

Hypovolemia or dehydration.

Renal failure in the form of anuria, if no therapeutic response to furosemide has been identified.

Renal failure due to poisoning with nephrotoxic or hepatotoxic drugs.

Severe hypokalemia.

Severe hyponatremia.

Precomatous or comatose conditions that are associated with hepatic encephalopathy.

Side effects

On the part of the hearing organs and the vestibular apparatus: hearing impairments, usually passing, especially in patients with renal failure, hypoproteinemia (for example, with nephrotic syndrome) and / or in case of too rapid iv administration of furosemide. cases of deafness, sometimes irreversible, have been reported after oral administration or administration of furosemide. tinnitus.

From the digestive system: nausea, vomiting, diarrhea, acute pancreatitis.

From the liver and biliary tract: cholestasis, increased levels of transaminases.

On the part of the kidneys and urinary system: tubulo-interstitial nephritis, an increase in urine volume, an increase in sodium in the urine, an increase in the level of chlorine in the urine, urinary retention (in patients with partial obstruction of the outflow of urine), nephrocalcinosis / nephrolithiasis in premature infants, renal failure.

From the side of metabolism, metabolism: electrolyte imbalance (including with clinical manifestations), dehydration and hypovolemia, especially in elderly patients, hyponatremia, hypochloremia, hypokalemia, hypocalcemia, hypomagnesemia, metabolic alkalosis, increased levels of TG, cholesterol, creatinine, uric acid in the blood, attacks of gout, an increase in the level of urea in the blood, a decrease in glucose tolerance, the course of diabetes mellitus can go from a latent form to a pronounced, Barter pseudo-syndrome against the background of wrong flax and / or prolonged use of furosemide.

From the nervous system: paresthesia, hepatic encephalopathy in patients with hepatocellular insufficiency.

From the cardiovascular system: hypotension, including orthostatic, vasculitis, thrombosis.

On the part of the blood and lymphatic system: hemoconcentration, thrombocytopenia, leukopenia, eosinophilia, agranulocytosis, aplastic or hemolytic anemia.

On the part of the immune system: severe anaphylactic and anaphylactoid reactions (in particular, accompanied by shock).

On the part of the skin and subcutaneous tissue: itching, urticaria, rash, bullous dermatitis, erythema multiforme, pemphigoid, exfoliative dermatitis, purpura, photosensitivity reactions, Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalized exanthematous pustulosis (DRESS) eosinophilia and systemic symptoms).

General disorders and reactions at the injection site: fever, local reactions, for example, pain after injection.

Congenital and hereditary / genetic disorders: increased risk of obstruction of the ductus arteriosus if furosemide is given to premature babies during the first days of life.

special instructions

During treatment with furosemide, it is necessary to ensure a constant outflow of urine. patients with partial obstruction of the outflow of urine require close attention, especially in the initial stages of treatment.

Treatment with furosemide requires regular medical supervision. Particularly careful monitoring is required:

- patients with arterial hypotension;

- patients who are at particular risk due to a significant decrease in blood pressure, for example, patients with severe stenosis of the coronary arteries or blood vessels that feed the brain;

- patients with latent or severe diabetes mellitus;

- patients with gout;

- patients with hepatorenal syndrome, that is, with functional renal failure, which is associated with severe liver diseases;

- patients with hypoproteinemia, which is associated with nephrotic syndrome (the effect of furosemide may be weakened simultaneously with the potentiation of ototoxicity). Careful dose titration is necessary;

- premature babies (possibly the development of nephrocalcinosis / nephrolithiasis); kidney monitoring and kidney ultrasonography are required.

Regular monitoring of sodium, potassium, and creatinine in blood plasma is recommended during furosemide therapy. Particularly careful monitoring is required for patients at high risk of electrolyte imbalances or in the event of significant additional fluid loss (for example, as a result of vomiting, diarrhea, or intense sweating). Hypovolemia or dehydration, as well as any significant disturbances in the electrolyte and acid-base balance, should be adjusted. This may require a temporary discontinuation of furosemide therapy.

Factors such as existing diseases (for example, cirrhosis of the liver, heart failure), concomitant use of drugs, and nutrition influence the development of electrolyte imbalance. For example, potassium deficiency may result from vomiting or diarrhea.

When using furosemide, it is advisable to recommend to the patient to eat foods high in potassium (baked potatoes, bananas, tomatoes, spinach, dried fruits). It should be remembered that when using furosemide, there may be a need for drug compensation for potassium deficiency.

Concomitant use with risperidone. In placebo-controlled studies of risperidone in elderly patients with dementia, a higher mortality rate was observed in patients receiving both furosemide and risperidone, compared with patients receiving only risperidone or only furosemide.

Caution should be exercised and the risks and benefits carefully considered before deciding on the use of such a combination or simultaneous treatment using other powerful diuretics. Dehydration should be avoided.

The drug contains lactose, so patients with rare hereditary galactose intolerance, lactase deficiency or glucose-galactose malabsorption syndrome should not use this drug.

Use during pregnancy and lactation. Pregnancy. Furosemide crosses the placental barrier. It should not be prescribed during pregnancy.

The period of breastfeeding. Furosemide passes into breast milk and may inhibit lactation. Women should stop breast-feeding during treatment with furosemide.

Children. For children, the dose should be reduced in accordance with body weight (see APPLICATION).

For children who cannot take the dosage form for oral administration, for example, premature infants and newborns, the possibility of using the form for parenteral administration should be considered.

The ability to influence the reaction rate when driving vehicles or other mechanisms. Some side effects (for example, an unexpected significant decrease in blood pressure) can impair the patient’s ability to concentrate and speed his reaction, so for the period of treatment you should refrain from driving vehicles or working with mechanisms.

Interactions

Combinations that are not recommended. in some cases, taking furosemide within 24 hours after chloral hydrate can cause hot flashes, increased sweating, an excited state, nausea, increased hell and tachycardia. therefore, the simultaneous use of furosemide and chloral hydrate is not recommended.

Furosemide may enhance the ototoxicity of aminoglycosides and other ototoxic drugs. Since this can lead to irreversible damage, these drugs should not be used simultaneously with furosemide.

Combinations requiring precautionary measures. In the case of the simultaneous use of cisplatin and furosemide, there is a risk of ototoxic effects. In addition, nephrotoxicity of cisplatin may increase if furosemide is not prescribed in low doses (for example, 40 mg to patients with normal renal function) and a positive fluid balance when the drug is used to achieve the effect of forced diuresis during cisplatin therapy.

Furosemide reduces the excretion of lithium salts and can lead to an increase in lithium levels in blood plasma, resulting in an increased risk of lithium toxicity, including a higher risk of cardiotoxic and neurotoxic effects of lithium. Thus, it is recommended that careful monitoring of lithium levels in patients receiving this combination therapy.

Patients receiving diuretics may experience severe arterial hypotension and impaired renal function, including cases of renal failure, especially when using an ACE inhibitor or angiotensin II receptor antagonist for the first time, or when using these drugs for the first time in high doses. It is necessary to decide whether to temporarily stop the use of furosemide, or at least reduce the dose of furosemide 3 days before the start of treatment, increase the dose of an ACE inhibitor or angiotensin II receptor antagonist.

Risperidone: care should be taken and the risk and benefit should be carefully weighed before deciding whether to take combination therapy or be used simultaneously with furosemide or other powerful diuretics.

Combinations to be used with caution. The simultaneous use of NSAIDs, including acetylsalicylic acid, can reduce the severity of the action of furosemide. In patients with dehydration or hypovolemia, NSAIDs can lead to acute heart failure. Under the influence of furosemide, salicylate toxicity may increase.

A decrease in the effectiveness of furosemide may occur after combined use with phenytoin.

The use of corticosteroids, carbenoxolone, licorice root in high doses and prolonged use of laxatives may increase the risk of hypokalemia.

Some electrolyte imbalances (such as hypokalemia, hypomagnesemia) can increase the toxicity of some other drugs (for example, digitalis drugs and drugs that cause Q-T prolongation syndrome).

If antihypertensive drugs, diuretics or other drugs with the property of lowering blood pressure are used simultaneously with furosemide, an even greater decrease in blood pressure should be expected.

Probenecid, methotrexate and other drugs, such as furosemide, undergo significant tubular secretion in the kidneys, can reduce the effectiveness of furosemide. Conversely, furosemide may decrease the excretion of these drugs by the kidneys. Conducting treatment with high doses (in particular, both furosemide and other drugs) can lead to an increase in their levels in the blood serum and the risk of side effects caused by furosemide or the concomitant therapy used.

The effectiveness of antidiabetic drugs and sympathomimetics, which tend to increase blood pressure (for example, epinephrine, norepinephrine), may decrease. The effect of curariform muscle relaxants or theophylline may be enhanced.

Possible increased harmful effects of nephrotoxic drugs on the kidneys.

Impaired renal function may develop in patients who receive furosemide therapy and high doses of individual cephalosporins.

The simultaneous use of cyclosporin A and furosemide is associated with an increased risk of gouty arthritis secondary to hyperuricemia caused by furosemide and impaired renal excretion of urates caused by cyclosporine.

Patients who are at high risk of nephropathy as a result of therapy with radiocontrast agents, when treated with furosemide, recorded a higher frequency of deterioration of kidney function after receiving radiocontrast substances compared to that in patients at high risk who underwent only intravenous hydration before radiocontrast agents .

Overdose

Symptoms: the clinical picture of acute or chronic overdose depends mainly on the degree and consequences of the loss of electrolytes and fluid and includes signs such as hypovolemia, dehydration, blood concentration, cardiac arrhythmias (including av-block and ventricular fibrillation). Symptoms of these disorders include severe arterial hypotension (progressing to shock), medical problems, thrombosis, delirium, peripheral paralysis, apathy, and confusion.

Treatment: there are no specific antidotes of furosemide. Therapy is symptomatic.

Storage conditions

In the original packaging at a temperature not exceeding 25 ° C. injection solution do not freeze.