Amfucin

Amphotericin B.

Each vial contains Amphotericin B 50 mg.

Pharmacology: Pharmacokinetics: There is little or no absorption of amphotericin B from the gastrointestinal tract. When given intravenously in the conventional colloidal form and in the usual increasing dosage regimens, peak plasma concentrations of 0.5 to 4 micrograms/mL have been reported; the average plasma concentration with maintenance doses of 400 to 600 micrograms/kg daily tends to be 500 nanograms/mL. Amphotericin B is highly bound to plasma proteins and is widely distributed, but passes into the Cerebrospinal Fluid only in small quantities. The plasma half-life is about 24 hours; with long-term use the terminal half-life increases to 15 days. Unchanged amphotericin B is excreted in small amounts slowly in the urine. Traces are present in the serum and urine several weeks after completion of treatment. Amphotericin B is not removed by haemodialysis.

Severe systemic fungal infections including aspergillosis, blastomycosis, candidiasis, coccidioidomycosis, cryptococcosis, histoplasmosis, mucormycosis, paracoccidioidomycosis, sporotrichosis, and the usual treatment of choice in fungal endocarditis, meningitis, peritonitis, or severe respiratory-tract infections.

Amphotericin B is given by intravenous infusion conventionally as a colloidal complex with sodium deoxycholate. Before starting therapy with any form of intravenous amphotericin B a test dose is usually advised and the patient observed carefully for about 30 minutes. An initial test dose (1 mg infused over 20 to 30 minutes) treatment usually starts with a daily dose of 250 mcg/kg, increased gradually to a maximum of 1 mg/kg daily; in seriously ill patients up to 1.5 mg/kg daily or on alternate days may be necessary. If treatment is stopped for longer than 7 days, it should be resumed at a dose of 250 micrograms/kg daily and increased gradually. The daily dose is infused over 2 to 4 hours at a concentration of 100 micrograms/mL in glucose 5%. Slower infusion, over up to 6 hours, may be necessary to reduce the incidence of acute toxic effects or as prescribed by the physician.
Directions for Reconstitution: Add 12 mL of sterile water for injection into the vial yielding 4mg/mL of amphotericin.
Shake the vial vigorously to completely disperse amphotericin. A yellow-colored suspension will be form.
Calculate amount of reconstituted amphotericin to be further diluted. Withdraw computed amount of reconstituted amphotericin into a sterile syringe.
Inject the syringe contents through into the appropriate amount of 5% Dextrose.
Amphotericin must be diluted with 5% Dextrose Injection to a final concentration of 1 to 2 mg/mL prior to administration. Lower concentrations (0.2 to 0.5 mg/mL) may be appropriate for infants and small children, so as to provide sufficient volume for infusion.
Note: Do not reconstitute with saline, add saline to the reconstituted solution nor mix with other drugs; presence of bacteriostatic agent in solution may cause precipitation. Reconstituted solution should be refrigerated (2 to 8°C) and use within 24 hours. Do not freeze. Discard any unused solution.

Contraindicated to the patients with pre-existing renal impairment and patients with hypersensitivity to the drug or any of its components.

Severe systemic reaction can occur with rapid intravenous infusion; potentially nephrotoxic, thus can cause and aggravate renal insufficiency especially in dehydrated state.

It is advisable to give a test dose and then to observe the patient carefully for about 30 minutes before starting treatment. Patients experiencing acute toxic reactions in whom treatment is essential may be given prophylactic treatment to ameliorate the reactions. To reduce the risk of vein irritation and infusion related adverse effects, the rate of intravenous infusion of conventional amphotericin B should be slow. Patients given any parenteral form of amphotericin B should be monitored for changes in renal function, liver function, serum electrolytes, and hematological status. If the Blood Urea Nitrogen or creatinine concentrations increase to clinically significant levels amphotericin B therapy should be interrupted or the dose reduced until renal function improves. Alternatively, a lipid amphotericin B preparation may be substituted. Treatment should be stopped if liver function tests are abnormal. Acute pulmonary, reactions have been noted in patients given amphotericin B during or shortly after leucocyte transfusions. Care should be taken not to confuse the dosage regimens for individual preparations, and in particular those of conventional and lipid formulations.

Common adverse effects which occur during or after intravenous infusion of amphotericin B include headache, nausea, vomiting, chills, fever, malaise, muscle and joint pains, anorexia, diarrhea, and gastrointestinal cramp. Hypertension, hypotension, cardiac arrhythmias including ventricular fibrillation and cardiac arrest, skin rashes, flushing, anaphylactoid reactions including bronchospasm and dyspnoea, blurred vision, tinnitus, hearing loss, vertigo, gastrointestinal bleeding, liver disorders, peripheral neuropathy, and convulsions have been reported occasionally. Some degree of nephrotoxicity occurs in almost all patients given amphotericin B intravenously.
Both tubular and glomerular damage occur; there may be improvement on cessation of therapy, but there is a risk of permanent renal impairment, particularly in patients given large cumulative doses (over 5 g). Renal tubular acidosis without systemic acidosis may develop. Use of amphotericin B is associated with increased urinary excretion of potassium and magnesium resulting in hypokalaemia and hypomagnesaemia respectively. Uric acid excretion is increased and nephrocalcinosis can occur. Reversible, normocytic, normochromic anemia develops in most patients given amphotericin B, possibly due to a direct suppressive effect on erythropoietin production. There are rare reports of thrombocytopenia, leucopenia, agranulocytosis, eosinophilia, and coagulation defects. Leukoencephalopathy has been reported rarely in patients also receiving total body irradiation. Amphotericin B solutions irritate the venous endothelium and may cause pain and thrombophlebitis at the injection site. Extravasation may cause tissue damage. After intrathecal injection amphotericin B may also cause irritation of the meninges, neuropathy with pain, impaired vision, and retention of urine. In general, adverse effects of lipid formulations have been similar to those of conventional amphotericin B, but are less frequent and less severe. Brief reversible episodes of renal impairment have been observed but these formulations have been considered to be safe enough to use in patients with renal impairment who could not be given conventional amphotericin B. Anaphylaxis has been reported rarely.

Most interactions involving amphotericin B have been observed during treatment with conventional formulations. Since lipid formulations appear to be less toxic, it may be anticipated that they will produce fewer serious interactions. Use of nephrotoxic antibacterials, ciclosporin or other nephrotoxic immunosuppressants, or parenteral pentamidine may lead to an increased risk of nephrotoxicity. Amphotericin B should not be given to patients receiving antineoplastics. Diuretics should generally be avoided in patients taking amphotericin B. If a diuretic has to be given then volume and electrolyte depletion should be monitored carefully. The potassium-depleting effect of amphotericin B may enhance the effects of neuromuscular blocking drugs and may increase the toxicity of digitalis glycosides; corticosteroids may enhance the depletion of potassium and their immunosuppressive effects may be detrimental in patients with severe fungal infections. Amphotericin B may increase the toxicity of flucytosine, but the combination is nonetheless used in severe infections for its synergistic activity. Renal excretion of zalcitabine may be reduced by amphotericin B.

Store at temperatures between 2°-8°C.

Antifungals

J02AA01 - amphotericin B ; Belongs to the class of antibiotics. Used in the systemic treatment of mycotic infections.

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