Drug information of quinupristin and dalfopristin

Mechanism of effect

Inhibition of mRNA translation by binding to the 50S subunit of bacterial ribosomes.

Pharmacodynamic

Predominantly independent of concentration once above four times the MIC of common Staphylococci and Streptococci

Pharmacokinetics

(7.5mg/kg dose at steady state) Cmax: 3.2 and 7.96mg/L (quinupristin and dalfopristin respectively) Half-life: 3.07 and 1.04 hours (quinupristin and dalfopristin respectively) Volume of distribution: 0.45 and 0.24L/kg (quinupristin and dalfopristin respectively)

Drug indications

This medication is a combination of 2 antibiotics. It is used to treat certain serious bacterial infections that have not responded to treatment with other antibiotics (resistant infections). This medication belongs to the class of antibiotics called streptogramins. Quinupristin/dalfopristin works by stopping the growth of bacteria.

Dosage

Skin & Skin Structure Infection

Indicated for complicated skin and skin structure infections caused by Staphylococcus aureus (methicillin susceptible) or Streptococcus pyogenes 

7.5 mg/kg IV q12hr for at least 7 days

Drug contraindications

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

Side effects

Nausea, vomiting, diarrhea, and headache may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you develop redness/swelling/pain/warming of the skin at the injection site. Flushing the IV line after each dose of this medication with dextrose 5 percent in water solution as directed will reduce the risk of vein irritation.

Tell your doctor right away if you have any serious side effects, including: joint/muscle pain, yellowing eyes/skin, blood in the urine.

Get medical help right away if you experience this rare but very serious side effect: chest pain.

This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Do not use anti-diarrhea or opioid medications if you have any of the following symptoms because these products may make them worse. Tell your doctor right away if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

Interactions

 In vitro drug interaction studies have shown that Synercid significantly inhibits cytochrome P450 3A4.

Points of recommendation

Prescribing Synercid in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.

Following completion of a peripheral infusion, the vein should be flushed with 5% Dextrose in Water solution to minimize venous irritation. DO NOT FLUSH with saline or heparin after Synercid administration because of incompatibility concerns.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver problems, high levels of bilirubin in the blood (hyperbilirubinemia).

This medication may cause live bacterial vaccines (such as typhoid vaccine) to not work as well. Do not have any immunizations/vaccinations while using this medication unless your doctor tells you to.

Pregnancy level

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.