amphotericin B Lipid -  (Amphotec ® and ABELCET):

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AMPHOTEC ® (Amphotericin B) injection, lipid complex

Microbiology

Mechanism of Action
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The active ingredient of AMPHOTEC, amphotericin B, is a polyene antibiotic that acts by binding to sterols (primarily ergosterol) in cell membranes of sensitive fungi, with subsequent leakage of intracellular contents and cell death due to changes in membrane permeability. Amphotericin B also binds to the sterols (primarily cholesterol) in mammalian cell membranes, which is believed to account for its toxicity in animals and humans.

Activity in vitro and in vivo
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AMPHOTEC is active in vitro against Aspergillus and Candida species. One hundred and twelve clinical isolates of four different Aspergillus species and 88 clinical isolates of five different Candida species were tested, with a majority of minimum inhibitory concentrations (MICs) < 1 µg/mL. AMPHOTEC is also active in vitro against other fungi. In vitro, AMPHOTEC is fungistatic or fungicidal, depending upon the concentration of the drug and the susceptibility of the fungal organism. However, standardized techniques for susceptibility testing for antifungal agents have not been established, and results of susceptibility studies do not necessarily correlate with clinical outcome.

AMPHOTEC is active in murine models against Aspergillus fumigatus, Candida albicans, Coccidioides immitis and Cryptococcus neoformans, and in an immunosuppressed rabbit model of aspergillosis in which endpoints were prolonged survival of infected animals and clearance of microorganisms from target organ(s). AMPHOTEC also was active in a hamster model of visceral leishmaniasis, a disease caused by infection of macrophages of the mononuclear phagocytic system by a protozoal parasite of the genus Leishmania. In this hamster model the endpoints were also prolonged survival of infected animals and clearance of microorganisms from target organ(s).


Drug Resistance
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Variants with reduced susceptibility to amphotericin B have been isolated from several fungal species after serial passage in cell culture media containing the drug and from some patients receiving prolonged therapy with amphotericin B deoxycholate. Although the relevance of drug resistance to clinical outcome has not been established, fungal organisms that are resistant to amphotericin B may also be resistant to AMPHOTEC.

Indications

INDICATIONS AND USAGE
AMPHOTEC is indicated for the treatment of invasive aspergillosis in patients where renal impairment or unacceptable toxicity precludes the use of amphotericin B deoxycholate in effective doses, and in patients with invasive aspergillosis where prior amphotericin B deoxycholate therapy has failed.

Dosage and Administration

DOSAGE AND ADMINISTRATION
The recommended dose for adults and pediatric patients is 3 - 4 mg/kg as required, once a day.

AMPHOTEC, reconstituted in Sterile Water for Injection, is administered diluted in 5% Dextrose for Injection by intravenous infusion at a rate of 1 mg/kg/hour. A test dose immediately preceding the first dose is advisable when commencing all new courses of treatment. A small amount of drug (e.g., 10 mL of the final preparation containing between 1.6 to 8.3 mg) should be infused over 15 to 30 minutes and the patient carefully observed for the next 30 minutes.

The infusion time may be shortened to a minimum of 2 hours for patients who show no evidence of intolerance or infusion-related reactions. If the patient experiences acute reactions or cannot tolerate the infusion volume, the infusion time may be extended.
 

ABELCET ®

Microbiology

Mechanism of Action
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The active component of ABELCET®, amphotericin B, acts by binding to sterols in the cell membrane of susceptible fungi, with a resultant change in the permeability of the membrane. Mammalian cell membranes also contain sterols, and damage to human cells is believed to occur through the same mechanism of action.

Activity in vitro and in vivo
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ABELCET® shows in vitro activity against Aspergillus sp.(n=3) and Candida sp.(n=10), with MICs generally < 1 µg/mL. Depending upon the species and strain of Aspergillus and Candida tested, significant in vitro differences in susceptibility to amphotericin B have been reported (MICs ranging from 0.1 to > 10 µg/mL). However, standardized techniques for susceptibility testing for antifungal agents have not been established, and results of susceptibility studies do not necessarily correlate with clinical outcome.

ABELCET® is active in animal models against Aspergillus fumigatus, Candida albicans, C. guillermondii, C. stellatoideae, and C. tropicalis, Cryptococcus sp., Coccidioidomyces sp., Histoplasma sp., and Blastomyces sp. in which end-points were clearance of microorganisms from target organ (s) and/or prolonged survival of infected animals.

Drug Resistance
Fungal species with decreased susceptibility to amphotericin B have been isolated after serial passage in culture media containing the drug, and from some patients receiving prolonged therapy. Although the relevance of drug resistance to clinical outcome has not been established, fungal species which are resistant to amphotericin B may also be resistant to ABELCET®.

Indications

ABELCET® is indicated for the treatment of invasive fungal infections in patients who are refractory to or intolerant of conventional amphotericin B therapy. This is based on open-label treatment of patients judged by their physicians to be intolerant to or failing conventional amphotericin B therapy

Dosage and Administration

The recommended daily dosage for adults and children is 5 mg/kg given as a single infusion. ABELCET® should be administered by intravenous infusion at a rate of 2.5 mg/kg/h. If the infusion time exceeds 2 hours, mix the contents by shaking the infusion bag every 2 hours.

Renal toxicity of ABELCET®, as measured by serum creatinine levels, has been shown to be dose dependent. Decisions about dose adjustments should be made only after taking into account the overall clinical condition of the patient.

Preparation of Admixture for Infusion
Shake the vial gently until there is no evidence of any yellow sediment at the bottom. Withdraw the appropriate dose of ABELCET® from the required number of vials into one or more sterile 20 mL syringes using an 18-gauge needle. Remove the needle from each syringe filled with ABELCET® and replace with the 5-micron filter needle supplied with each vial. Each filter needle may be used to filter the contents of up to four vials. Insert the filter needle of the syringe into an IV bag containing 5% Dextrose Injection USP, and empty the contents of the syringe into the bag. The final infusion concentration should be 1 mg/mL. For pediatric patients and patients with cardiovascular disease the drug may be diluted with 5% Dextrose Injection to a final infusion concentration of 2 mg/mL. Before infusion, shake the bag until the contents are thoroughly mixed. Do not use the admixture after dilution with 5% Dextrose Injection if there is any evidence of foreign matter. Vials are for single use. Unused material should be discarded. Aseptic technique must be strictly observed throughout handling of ABELCET®, since no bacteriostatic agent or preservative is present.

DO NOT DILUTE WITH SALINE SOLUTIONS OR MIX WITH OTHER DRUGS OR ELECTROLYTES as the compatibility of ABELCET® with these materials has not been established. An existing intravenous line should be flushed with 5% Dextrose Injection before infusion of ABELCET®, or a separate infusion line should be used. DO NOT USE AN IN-LINE FILTER.

The diluted ready-for-use admixture is stable for upto 48 hours at 2° to 8°C (36° to 46°F) and an additional 6 hours at room temperature.
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David F. McAuley, Pharm.D., R.Ph.  GlobalRPh Inc.