Patient warning issued about new drug linezolid

FDA warns about effects on immune system

Linezolid — a heralded new weapon against drug-resistant infections — may cause some types of immune suppression in certain patients, according to a recent warning by the manufacturer and the Food and Drug Administration (FDA).

A label-change warning was issued by the
distributor of the drug (brand name Zyvox, Pharmacia and UpJohn, Kalamazoo, MI) and posted on the FDA’s web site.

Linezolid (injection and tablets for oral suspension) is a synthetic antibacterial agent of the oxazolidinone class. It is indicated for the treatment of adult patients with vancomycin-resistant Enterococcus faecium (VRE), including cases with concurrent bacteremia; nosocomial pneumonia; complicated and uncomplicated skin and skin structure infections; and community-acquired pneumonia, including cases with concurrent bacteremia.

Calls to the company seeking additional clarification were not successful, but the letter states that the Food and Drug Administration (FDA) has received reports from the spontaneous reporting system of myelosuppression in patients receiving the drug.

To communicate this important safety information, the following information has been added to the warnings section of the labeling for linezolid:

"Myelosuppression (including anemia, leukopenia, pancytopenia, and thrombocytopenia) has been reported in patients receiving linezolid. In cases where the outcome is known, when linezolid was discontinued, the affected hematologic parameters have risen toward pretreatment levels.

"Complete blood counts should be monitored weekly in patients who receive linezolid, particularly in those who receive linezolid for longer than two weeks, those with pre-existing myelosuppression, those receiving concomitant drugs that produce bone marrow suppression, or those with a chronic infection who have received previous or concomitant antibiotic therapy.

"Discontinuation of therapy with linezolid should be considered in patients who develop or have worsening myelosuppression.

"Changes consistent with the added warning have also been made to the adverse reactions section, which states in part that the events have been chosen for inclusion due to either their seriousness, frequency of reporting, possible causal connection to linezolid, or a combination of these factors.

"Because they are reported voluntarily from
a population of unknown size, estimates of frequency cannot be made and a causal relationship cannot be precisely established," the label change states.

[Infection control professionals who suspect any cases of myelosuppression in patients treated with linezolid may contact Pharmacia at (800) 253-8600, ext. 38244. Contact the FDA MedWatch program at MedWatch, HF-2, FDA, 5600 Fishers Lane, Rockville, MD 20857. Telephone: (800) FDA-1088. Fax: (800) FDA-0178. Web site: http://www.accessdata.fda.gov/scripts/medwatch/.]

Mouthwash may pose patient risk

In other FDA action that may be important to ICPs, a voluntary product recall is under way for contaminated mouth rinse that could pose an infection risk to immunocompromised hospital patients.

A letter posted on the FDA’s web site states that a product recall initiated on Feb. 28, 2001, by Chester Labs in Cincinnati has been expanded
to include additional lots of System TLC 4 oz Mouth Rinse, product number 535-4. Lot number 0049001 is being recalled due to contamination with Burkholderia cepacia.

The product presents a serious adverse health situation, as infections from these bacteria are difficult to treat, and can be associated with high morbidity and mortality rates, especially in immunocompromised hospital patients, the company states.

The recall also has been expanded to include these lot numbers: 0049002, 0053003, 0054004, 0055005, 0056006, 0060007, and 0131009.

The other lot numbers are being recalled because they do not meet the manufacturer’s product specifications.

Chester Labs is contacting all distributors that may have received these lot numbers.

The company advises that purchasers of the product examine their stock and remove any containers of the mouth rinse.

More details on the recall are available from the company at (800) 354-9709.