In the U.S.—

• Antibacterial, systemic

Quinupristin ( qui-NYOO-pris-tin) and dalfopristin (dal-FOE-pris-tin ) belong to the family of medicine called antibiotics. Antibiotics are medicines used in the treatment of infections caused by bacteria. They work by killing bacteria or preventing their growth. Quinupristin and dalfopristin will not work for colds, flu, or other virus infections.

Quinupristin and dalfopristin injection is used to treat infection of the skin or the blood. It may also be used for other conditions as determined by your doctor. It is given by injection and is used mainly for serious infection for which other medicine may not work.

Quinupristin and dalfopristin injection is available only with your doctor's prescription, in the following dosage form:

Parenteral
• Injection (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For quinupristin and dalfopristin, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to quinupristin or dalfopristin. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Quinupristin and dalfopristin have not been studied in pregnant women. However, they have not been shown to cause birth defects or other problems in animal studies.

Breast-feeding—It is not known whether quinupristin and dalfopristin pass into breast milk. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breast-feeding. Mothers who are taking this medicine and who wish to breast-feed should discuss this with their doctor.

Children—Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of quinupristin and dalfopristin in children under 16 years old with use in other age groups.

Older adults—In studies of patients 65 years or older, quinupristin and dalfopristin have not been shown to cause different side effects or problems than they do in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving quinupristin and dalfopristin it is especially important that you tell your doctor if you are taking any of the following:

• Cyclosporine (e.g., Sandimmune) or
• Midazolam (e.g., Versed) or
• Nifedipine (e.g., Adalat) or
• Terfenadine (e.g., Seldane)—Use of these medicine with quinupristin and dalfopristin may increase their effects because of slower removal of the medicine from the body.

• Liver disease—Liver disease may increase blood levels of this medicine, increasing the chance of side effects

Some medicine given by injection may sometimes be given at home to patients who do not need to be in the hospital. If you are using this medicine at home, make sure you clearly understand and carefully follow your doctor's instructions.

To help clear up your infection completely, this medicine must be given for the full time of treatment, even if you begin to feel better after a few days. Also, it works best when there is a constant amount in the blood. To help keep the amount constant, quinupristin and dalfopristin must be given on a regular schedule.

Dosing—

The dose of quinupristin and dalfopristin will be different for different patients. The dose that is used may depend on a number of things, including what the medicine is being used for, the patient's size, and whether or not other medicines are also being taken. If you are receiving quinupristin and dalfopristin at home, follow your doctor's orders or the directions on the label.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• More common
  • Swelling, redness, or pain at the injection area 
  
  

• Less common
  • Joint pain;  muscle pain;  redness, burning sensation, or pain under the skin usually in the area of injection 
  
  

• Rare
  • Chest pain;  fast heartbeat;  blood in urine;  redness, burning sensation, or pain in vagina;  severe bloody diarrhea;  skin rash with red patches;  hives 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.