Before Using This Medicine

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.

Other medical problems—The presence of other medical problems may affect the use of quinupristin and dalfopristin. Make sure you tell your doctor if you have any other medical problems, especially:

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