Potentially Fatal Glucose Monitoring Errors with Icodextrin

The Institute for Safe Medication Practices (ISMP) is warning again about the possibility of potentially fatal glucose monitoring errors in patients receiving products that contain other sugars. These include oral xylose, parenterals that contain maltose or galactose, and peritoneal dialysis solutions that contain icodextrin. This issue was also reported in an earlier edition of FDA Patient Safety News.

The problem is that some point-of-care glucose meters use a type of test strip that cannot distinguish between glucose and other sugars. So in these cases, the meter's reading of the test strip will reflect both the patient's actual blood glucose and the other sugar the patient has received. This falsely elevated reading can lead to aggressive insulin treatment, which can result in hypoglycemic shock and death.

The latest ISMP report concentrates on Extraneal, a peritoneal dialysis solution containing icodextrin, which is metabolized in the body to maltose. The ISMP report notes that FDA has received 18 reports of hypoglycemic adverse events associated with Extraneal since it was first marketed in 2002. In three cases, the patient or a family member told the hospital staff about the potential problem, but the staff still relied on erroneous readings from portable monitors.

In one of the reported cases, a 62 year-old hospitalized dialysis patient on Extraneal therapy died from severe hypoglycemia because his treatment was based on falsely elevated glucose readings from an inappropriate meter. This occurred despite glucose readings from the hospital lab that were strikingly lower than those produced by the meter.

Test strips that cannot distinguish between glucose and other sugars contain reagents called GDH-PQQ or GDO. Other types of meters use reagents that are capable of distinguishing glucose from the other sugars. These reagents are called GDH-NAD, GDH-FAD, glucose oxidase and glucose hexokinase. It is important to check the package insert that comes with the test strips to determine which type of reagent they contain.

Here is what ISMP recommends to prevent these glucose monitoring errors in hospitals. Consider using only glucose meters that use test strips that can distinguish between glucose and other sugars. If you use meters and strips that cannot distinguish between the sugars, take these additional precautions:

• On admission and periodically during the hospital stay, find out whether the patient is receiving medications containing other sugars. If so, monitor glucose using only hospital laboratory methods.

• Periodically verify point-of-care blood glucose readings with laboratory results. This can detect errors in glucose meter readings early enough to prevent harm. This is especially important in patients who are unconscious or unable to communicate, since it may be difficult to ascertain the symptoms of hypoglycemia or the medication history.

• Educate the staff about this potentially fatal problem, and consider safeguards such as drug interaction alerts in computer order entry systems, patient profiles and charts.

Additional Information:

ISMP Medication Safety Alert! FDA Advise-ERR: Prevent dangerous drug-device interaction causing falsely elevated glucose levels. June 19, 2008.
http://www.ismp.org/Newsletters/acutecare/articles/20080619.asp

FDA Drug Safety Newsletter. Icodextrin (marketed as EXTRANEAL) and Point-of-Care Glucose Monitoring. Volume 1, Number 4. Summer 2008.
http://www.fda.gov/cder/dsn/2008_summer/postmarketing.htm#icodextrin

FDA Center for Biologics Evaluation and Research. Fatal Iatrogenic Hypoglycemia: Falsely Elevated Blood Glucose Readings with a Point-of-Care Meter Due to a Maltose-Containing Intravenous Immune Globulin Product. April 17, 2008.
http://www.fda.gov/cber/safety/glucfalse.htm

FDA MedWatch Safety Alert - Parenteral Maltose/Parenteral Galactose/Oral Xylose-Containing Products. 2005.
http://www.fda.gov/medwatch/safety/2005/safety05.htm#maltose