Synercid^® I.V.
(quinupristin and dalfopristin for injection)

Rx only

One of Synercid's approved indications is for the treatment of patients with serious or life-threatening infections associated with vancomycin-resistant Enterococcus faecium (VREF) bacteremia. Synercid has been approved for marketing in the United States for this indication under FDA's accelerated approval regulations that allow marketing of products for use in life-threatening conditions when other therapies are not available. Approval of drugs for marketing under these regulations is based upon a demonstrated effect on a surrogate endpoint that is likely to predict clinical benefit.

Approval of this indication is based upon Synercid's ability to clear VREF from the bloodstream, with clearance of bacteremia considered to be a surrogate endpoint. There are no results from well-controlled clinical studies that confirm the validity of this surrogate marker. However, a study to verify the clinical benefit of therapy with Synercid on traditional clinical endpoints (such as cure of the underlying infection) is presently underway.

Synercid^® (quinupristin and dalfopristin powder for injection) I.V., a streptogramin antibacterial agent for intravenous administration, is a sterile lyophilized formulation of two semisynthetic pristinamycin derivatives, quinupristin (derived from pristinamycin I) and dalfopristin (derived from pristinamycin IIA) in the ratio of 30:70 (w/w).

Quinupristin is a white to very slightly yellow, hygroscopic powder. It is a combination of three peptide macrolactones. The main component of quinupristin (>88.0%) has the following chemical name: N-[(6R,9S,10R,13S,15aS,18R,22S,24aS)-22-[p-(dimethyl-amino)benzyl]-6-ethyldocosahydro-10,23-dimethyl-5,8,12,15,17,21,24-heptaoxo-13-phenyl-18-[[(3S)-3-quinuclidinylthio] methyl]-12H-pyrido[2,1-f]pyrrolo-[2,1-l][1,4,7,10,13,16] oxapentaazacyclononadecin-9-yl]-3-hydroxypicolinamide.

The main component of quinupristin has an empirical formula of C₅₃H₆₇N₉O₁₀S, a molecular weight of 1022.24 and the following structural formula:

Dalfopristin is a slightly yellow to yellow, hygroscopic, powder. The chemical name for dalfopristin is: (3R,4R,5E,10E,12E,14S,26R,26aS)-26-[[2-(diethylamino)ethyl]sulfonyl]-8,9,14,15,24,25,26,26a-octahydro-14-hydroxy-3-isopropyl-4,12-dimethyl-3H-21,18-nitrilo-1H,22H-pyrrolo[2,1-c][1,8,4,19]-dioxadiazacyclotetracosine-1,7,16,22(4H,17H)-tetrone.

Dalfopristin has an empirical formula of C₃₄H₅₀N₄O₉S, a molecular weight of 690.85 and the following structural formula:

Elderly: The pharmacokinetics of quinupristin and dalfopristin were studied in a population of elderly individuals (range 69 to 74 years). The pharmacokinetics of the drug products were not modified in these subjects.

Quantitative methods are used to determine antimicrobial minimum inhibitory concentrations (MICs). These MICs provide estimates of the susceptibility of microorganisms to antimicrobial compounds. The MICs should be determined using a standardized procedure. Standardized procedures are based on a dilution¹ method (broth or agar) or equivalent using standardized inoculum concentrations, and standardized concentrations of quinupristin/dalfopristin (Synercid) in a 30:70 ratio made from powder of known potency. The MIC values should be interpreted according to the following criteria:

A report of “Susceptible” indicates that the pathogen is likely to be inhibited if the concentration of the antimicrobial compound in the blood reaches usually achievable levels. A report of “Intermediate” indicates that the result should be considered equivocal, and if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where high dosage of drug can be used. This category provides a buffer zone which prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of “Resistant” indicates that the pathogen is not likely to be inhibited if the antimicrobial compound in the blood reaches the concentrations usually achievable; other therapy should be selected.

Quantitative methods that require measurement of zone diameters also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. One such standardized procedure² requires the use of standardized inoculum concentrations. This procedure uses paper disks impregnated with 15 μg quinupristin/dalfopristin in a ratio of 30:70 (Synercid) to test the susceptibility of microorganisms to quinupristin/dalfopristin. Reports from the laboratory providing results of the standard single-disk susceptibility test with a 15 μg quinupristin/dalfopristin disk should be interpreted according to the following criteria:

Interpretation should be as stated above for results using dilution techniques. Interpretation involves correlation of the diameter obtained in the disk test with the MIC for quinupristin/dalfopristin.

Synercid is indicated in adults for the treatment of the following infections when caused by susceptible strains of the designated microorganisms.

Synercid is indicated for the treatment of patients with serious or life-threatening infections associated with vancomycin-resistant Enterococcus faecium (VREF) bacteremia. (See CLINICAL STUDIES.)

One of Synercid's approved indications is for the treatment of patients with serious or life-threatening infections associated with vancomycin-resistant Enterococcus faecium (VREF) bacteremia. Synercid has been approved for marketing in the United States for this indication under FDA's accelerated approval regulations that allow marketing of products for use in life-threatening conditions when other therapies are not available. Approval of drugs for marketing under these regulations is based upon a demonstrated effect on a surrogate endpoint that is likely to predict clinical benefit.

Approval of this indication is based upon Synercid's ability to clear VREF from the bloodstream, with clearance of bacteremia considered to be a surrogate endpoint. There are no results from well-controlled clinical studies that confirm the validity of this surrogate marker. However, a study to verify the clinical benefit of therapy with Synercid on traditional clinical endpoints (such as cure of the underlying infection) is presently underway.

Complicated skin and skin structure infections caused by Staphylococcus aureus (methicillin susceptible) or Streptococcus pyogenes. (See CLINICAL STUDIES.)

Synercid is contraindicated in patients with known hypersensitivity to Synercid, or with prior hypersensitivity to other streptogramins (e.g., pristinamycin or virginiamycin).

The safety of Synercid was evaluated in 1099 patients enrolled in 5 comparative clinical trials. Additionally, 4 non-comparative clinical trials (3 prospective and 1 retrospective in design) were conducted in which 1199 patients received Synercid for infections due to Gram-positive pathogens for which no other treatment option was available. In non-comparative trials, the patients were severely ill, often with multiple co-morbidities or physiological impairments, and may have been intolerant to or failed other antibacterial therapies.

There are four reports of patients receiving Synercid doses at up to three times that recommended (7.5 mg/kg). No adverse events were considered possibly or probably related to Synercid overdose. Signs of acute overdosage may include dyspnea, emesis, tremors, and ataxia as seen in animals given extremely high doses (50 mg/kg) of Synercid. Patients who receive an overdose should be carefully observed and given supportive treatment. Synercid is not removed by peritoneal dialysis or by hemodialysis.

Synercid should be administered by intravenous infusion in 5% Dextrose in Water solution over a 60-minute period. (See WARNINGS.) The recommended dosage for the treatment of infections is described in the table below. An infusion pump or device may be used to control the rate of infusion. If necessary, central venous access (e.g., PICC) can be used to administer Synercid to decrease the incidence of venous irritation.

The minimum recommended treatment duration for Complicated Skin and Skin Structure Infections is seven days. For Vancomycin-Resistant Enterococcus faecium infection, the treatment duration should be determined based on the site and severity of the infection.

• Reconstitute the 500 mg single dose vial by slowly adding 5 mL of 5% Dextrose in Water or Sterile Water for injection.

  Reconstitute the 600 mg single dose vial by slowly adding 6 mL of 5% Dextrose in Water or Sterile Water for injection.

• GENTLY swirl the vial by manual rotation without shaking to ensure dissolution of spans while LIMITING FOAM FORMATION.
• Allow the solution to sit for a few minutes until all the foam has disappeared. The resulting solution should be clear. Vials reconstituted in this manner will give a solution of 100 mg/mL. CAUTION: FURTHER DILUTION REQUIRED BEFORE INFUSION.
• According to the patient's weight, the reconstituted Synercid solution should be added to 250 mL of 5% Dextrose solution. An infusion volume of 100 mL may be used for central line infusions.
• If moderate to severe venous irritation occurs following peripheral administration of Synercid diluted in 250 mL of Dextrose 5% in water, consideration should be given to increasing the infusion volume to 500 or 750 mL, changing the infusion site, or infusing by a peripherally inserted central catheter (PICC) or a central venous catheter.
• The desired dose should be administered by intravenous infusion over 60 minutes.

NOTE: As for other parenteral drug products, Synercid should be inspected visually for particulate matter prior to administration.

DO NOT DILUTE WITH SALINE SOLUTIONS BECAUSE SYNERCID IS NOT COMPATIBLE WITH THESE AGENTS. Synercid should not be mixed with, or physically added to, other drugs except for the following drugs where compatibility by Y-site injection has been established:

If Synercid is to be given concomitantly with another drug, each drug should be given separately in accordance with the recommended dosage and route of administration for each drug.

With intermittent infusion of Synercid and other drugs through a common intravenous line, the line should be flushed before and after administration with 5% Dextrose in Water solution.

Synercid is supplied as a sterile lyophilized pyrogen-free preparation in single-dose 10 mL type I glass vials with gray elastomeric closure, and aluminum seal with a dark blue flip-off cap for the 500 mg vial and a red flip-off cap for the 600 mg vial.

In the non-comparative trials, patients often presented with multiple co-morbidities and/or physiologic impairments, and may have been intolerant to or failed other antibacterial therapies.

Discontinuations of therapy because of adverse reactions which were probably or possibly due to drug therapy occurred more than four times as often in the Synercid group than in the comparator group. Approximately half of the discontinuations in the Synercid arm were due to venous adverse events. (See ADVERSE REACTIONS: Clinical Reactions: Skin and Skin Structure Studies.)

Keep out of the reach of children.

• National Committee for Clinical Laboratory Standards, Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically– Fourth Edition; Approved Standard. NCCLS Document M7-A4 (ISBN 1-56238-309-4). NCCLS, 940 West Valley Road, Suite 1400, Wayne, PA 19087-1898, 1997.
• National Committee for Clinical Laboratory Standards, Performance Standards for Antimicrobial Disk Susceptibility Tests - Sixth Edition; Approved Standard. NCCLS document M2-A6 (ISBN 1-56238-308-6). NCCLS, 940 West Valley Road, Suite 1400, Wayne, PA 19087-1898, 1997.

Distributed by: Monarch Pharmaceuticals, Inc., Bristol, TN 37620

Manufactured by: DSM Pharmaceuticals, Inc., Greenville, NC 27834

Prescribing Information as of July 2003