Pharmacology: Pharmacological action – diuretic, natriuretic. It operates throughout the thick segment of the ascending knee of the Henle loop and blocks the reabsorption of 15-20% of filtered sodium ions. It is secreted into the lumen of the proximal renal tubules. Increases the excretion of bicarbonates, phosphates, calcium, magnesium and potassium, increases the pH of urine. Has secondary effects due to the release of intrarenal mediators and redistribution of the intrarenal blood flow. Quickly and fairly fully absorbed in any route of administration. Bioavailability with oral administration is usually 60-70%. Binding to plasma proteins is 91-97%. T_1 / 2 0.5-1 h. In the liver it undergoes biotransformation with the formation of inactive metabolites (mainly – glucuronide). Excreted by 88% of the kidneys and 12% – with bile.
Side effects: Hypotension, incl. postural, collapse, thromboembolism, thrombophlebitis (especially in the elderly), hypokalemia, hypomagnesemia, hyponatremia, glucose intolerance, hyperuricemia, gout, increased LDL cholesterol (at higher doses), violation of KHS (hypochloraemic alkalosis), hypercalciuria, the liver , intrahepatic cholestasis, pancreatitis, diarrhea, constipation, nausea, vomiting, anorexia, inner ear damage, hearing loss, blurred vision, confusion, nervousness, headache, dizziness, paresthesia I, weakness, muscle spasms, bladder spasms, chills, fever, thrombocytopenia, aplastic anemia, leukopenia, systemic vasculitis, interstitial nephritis, hematuria, necrotizing vasculitis, exfoliative dermatitis, erythema multiforme, impotence, Photosensitivity, hives, itching.
Dosing and Administration
In / in (rarely in / m), parenteral administration is advisable to implement in cases where there is no possibility of taking it inside – in urgent situations or with a pronounced edematic syndrome. Edema syndrome: the initial dose is 40 mg. In / in the introduction is carried out for 1-2 minutes; In the absence of a diuretic response every 2 hours, injected in an increased 50% dose until an adequate diuresis is achieved. The average daily dose for intravenous administration in children is 0.5-1.5 mg / kg, the maximum dose is 6 mg / kg. Patients with reduced glomerular filtration and low diuretic response are prescribed in large doses – 1-1.5 g. The maximum single dose is 2 g. Inside, in the morning, before meals, the average single initial dose is 20-80 mg; In the absence of a diuretic response, the dose is increased by 20-40 mg every 6-8 hours until an adequate diuretic response is obtained. A single dose, if necessary, can be increased to 600 mg or more (required with a decrease in glomerular filtration and hypoproteinemia). With arterial hypertension, 20-40 mg is prescribed, in the absence of a sufficient reduction in blood pressure, other antihypertensive drugs must be added to the treatment. When furosemide is added to the already prescribed antihypertensive drugs, their dose should be reduced by a factor of 2. The initial single dose in children is 2 mg / kg, the maximum dose is 6 mg / kg.
In case of an overdose of Lasix, arterial hypotension, electrolyte balance disturbance, dizziness, dry mouth, and visual impairment are most often observed. The treatment is aimed at restoring the water-electrolyte balance and normalizing the BCC.