In this issue...
Revision to the Treatment Recommendations for Latent Tuberculosis Infection
World Drug-Resistance Information
The Golden Rule of Interjurisdictional Transfers, Both Intrastate and Interstate
New Antiviral Medications and the Treatment of TB
Hypoglycemia and Hyperglycemia with Fluoroquinolones
The August 8, 2003 Morbidity and Mortality Weekly Report (MMWR) provides an update on the guidelines for treating latent tuberculosis (TB) infection (LTBI). Specifically, these revised recommendations indicate that the 2-month regimen of Rifampin plus Pyrazinamide (RZ) should generally not be offered to LTBI patients. Note: The revised LTBI recommendation does not apply to the appropriate use of Rifampin and Pyrazinamide for patients with active TB disease.
Data from the Centers for Disease Control and Prevention (CDC) indicate that between October 2000 and June 2003, there were 48 cases of confirmed RZ-associated severe liver injuries, and 11 of these cases died. In another study, the administration of RZ for the treatment of LTBI resulted in high rates of hospitalization and death due to liver injury. Consequently, the ATS and CDC, with ISDA endorsement, now recommend against the general use of RZ for LTBI patients.
The treatment of LTBI remains a key step in the effort to eliminate tuberculosis. The preferred regimen for treating LTBI is the 9-month therapy with Isoniazid (INH). In light of the current RZ recommendation, it is important to note that alternative drug regimens for LTBI do exist, and are available and safe. Such regimens include INH for 6 months or Rifampin for 4 months.
The RZ recommendation resulted from reports of toxicity and not because of its efficacy. Therefore, patients receiving a 2-month course of 4 anti-TB drugs to treat suspected active TB disease, and who later receive a diagnosis of not having active TB disease, will have received adequate LTBI treatment after completing this two months of therapy.
The full MMWR article:
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5231a4.htm
Occasionally, the Division of TB Control (DTC) receives questions on drug resistance in other countries. These queries are frequently made before the initiation of treatment on foreign-born patients for active TB disease or LTBI.
Regardless of country of origin, all newly diagnosed TB cases and suspects should receive the standard 4-drug treatment regimen, until drug susceptibility tests indicate otherwise, unless there is reason to suspect drug resistance (e.g. previous TB treatment, link to a known resistant case). Please discuss with DTC - prior to the start of treatment - any TB case being considered for a regimen other the standard 4-drug therapy. The web site listed below provides the most recent data on drug resistance from countries around the world.
http://www.who.int/emc-documents/antimicrobial_resistance/whocdstb2000278c.html
Occasionally, DTC receives positive comments on the completeness of a TB referral, as well as the efficiency and high quality of the communication between jurisdictions. Just as occasionally, however, DTC receives complaints about the poor quality of TB referrals and the lack of information provided by other states. DTC would like to provide some tips to help these TB referrals go as smoothly, efficiently, and positively as possible.
When completing a TB referral...
• Please make sure to record all of the new patient-locator information accurately. Referral forms that only provide a city and state are not acceptable and are generally not forwarded without a telephone number of another contact information.
• Please correctly indicate the patient classification: case, suspect, contact, LTBI, etc.
• Please indicate if the lab information and medication list provided on the referral form is that of the referred individual or the index case.
• Attaching copies of select records can be helpful when transferring a confirmed case or suspect.
• Send all interstate referrals to DTC first, regardless of any contacts made with the jurisdiction receiving the transferring patient. Occasionally, some states have not acted upon referrals unless specifically sent by the state TB control office.
• Please complete and send your interjurisdictional referral the way in which you would like to receive one.
Recently, two new antiviral medications, Reyataz (atazanavir sulfate) and Emtriva (emtricitabine), were added to the Virginia Department of Health (VDH) formulary for the treatment of HIV-1 infection. The benefits of these medications is that they both allow for a once-a-day dosing schedule.
Current prescribing information for Reyataz, a protease inhibitor, states that Rifampin should not be administered concurrently. Rifabutin can be substituted for patients with active TB disease taking Reyataz, however, Rifabutin dose adjustments are necessary because Reyataz increases the serum concentration of rifabutin. Recommendations are that the Rifabutin dose should be reduced up to 75% - 150 mg every other day or 3 times per week. Full Reyataz prescribing information: Reyataz (pdf file)
Emtriva, a NRTI, does not inhibit any of the CYP 450 isoforms in vitro, including the CYP3A4 isoform which is key in the use of both Rifampin and rifabutin. Based on two studies, the potential for CYP450-mediated interactions involving Emtriva and other medicinal products is low.
Full Emtriva prescribing information: Emtriva (pdf file)
Recent Canadian reports indicate that episodes of both hypoglycemia and hyperglycemia following the use of gatifloxacin can occur. Similar episodes of hypoglycemia have been reported to the USFDA with the use of ciprofloxacin, levofloxacin and moxifloxacin. There have been deaths associated with these reactions even in patients without a history of diabetes. Additional patients have required insulin for the treatment of hyperglycemia. Typically, fluoroquinolones may be used in the treatment of drug resistant TB, or in cases of active TB disease where a patient is unable to tolerate one of the first line drugs. Patients taking any of these medications mentioned should be monitored regularly for hyperglycemic and hypoglycemic signs and symptoms, and evaluated further as necessary.
This information was published in "The Medical Letter," Vol. 45 (1162), 8/4/2003
http://www.medicalletter.org