Stronger Warnings for the Fluoroquinolone Antibiotic Gatifloxacin (TEQUIN)

Stronger warnings have been added to the professional product label, or “package insert,” for the fluoroquinolone antibiotic gatifloxacin (TEQUIN) about possible heart rhythm disturbances and problems with blood sugar control. This drug was approved by the Food and Drug Administration (FDA) in October 2001 and its marketing brought to nine the number of fluoroquinolone antibiotics on the market.

Gatifloxacin is produced by the Bristol-Myers Squibb Company of Princeton, NJ.

We listed gatifloxacin as a Do Not Use drug because it joined sparfloxacin (ZAGAM) and moxifloxacin (AVELOX) as fluoroquinolone antibiotics that can cause a dangerous abnormality in the heart’s electrical conduction known as QT_c prolongation that can lead to fatal heart rhythm disturbances (see Worst Pills, Best Pills News July 2002).

The QT interval is the length of time it takes the ventricles (large chambers of the heart) to discharge and recharge electrically. The QT_c interval is measured on an electrocardiogram (EKG or ECG) in milliseconds (msec); the subscript “c” indicates that the QT interval has been corrected for the patient’s heart rate. Prolongation of the QT interval can lead to heart rhythm disturbances (cardiac arrhythmias) such as torsade de pointes. Torsade de pointes is a French phrase that means “twisted point” that describes the appearance of this type of rhythm disturbance on the EKG tracing.

The bolded warning in gatifloxacin’s professional product labeling has been strengthened with the boxed statement below.

The professional product labeling for gatifloxacin also warns that it has not been studied in combination with other drugs that prolong the QT interval and should be used with caution when given with drugs such as cisapride (PROPULSID), erythromycin (EES), antipsychotic drugs such as thioridazine (MELLARIL) and tricyclic antidepressants such as amitriptyline (ELAVIL) and imipramine (TOFRANIL). We do not think it is worth the risk of taking gatifloxacin together with these drugs when there are other antibiotics that are safer and just as effective.

The new warnings also include an expanded section on problems with blood sugar control associated with the use of gatifloxacin. Disturbances of blood sugar, including high blood sugar (hyperglycemia) and low blood sugar (hypoglycemia), have been reported in diabetic patients using gatifloxacin. In addition, elderly patients with other medical problems or who are taking drugs to treat type 2, or adult onset, diabetes appear to be at an increased risk of developing high blood sugar levels.

Patients who develop low blood sugar while on gatifloxacin should take immediate measures to increase their blood sugar by eating, stopping gatifloxacin, and contacting their physician at once. The signs of low blood sugar include: anxiety, blurred vision, cold sweats or cool, pale skin, confusion, difficulty concentrating, drowsiness, increased hunger, headache, nausea, nervousness, nightmares and restless sleep, rapid heart beat, shakiness, slurred speech, unsteady walk, abnormal tiredness or weakness and unusual weight gain.

Those who may develop high blood sugar while on gatifloxacin should contact their physician at once before taking additional gatifloxacin. The signs of high blood sugar include: blurred vision, drowsiness, dry, flushed skin, breath smells of fruit, increased urination, loss of appetite, tiredness, abnormal thirst, deep rapid breathing, dizziness, dry mouth, headache, stomach ache, nausea, vomiting and swelling of feet and/or legs.

The new warnings also recommend careful monitoring of blood sugar levels when gatifloxacin is prescribed to patients with diabetes or patients at risk for developing high blood sugar. We can think of no reason why this antibiotic should be prescribed to a diabetic.

All fluoroquinolone antibiotics can cause inflammation of tendons and sometimes rupture, most commonly in the Achilles tendon that connects the back of the heel to the calf muscle. Tendon rupture can require surgical repair or may result in prolonged disability. Gatifloxacin or any fluoroquinolone antibiotic should be stopped immediately if unexpected tendonitis occurs, and your doctor should be contacted as soon as possible. The Health Research Group petitioned the FDA in 1996 to require a tendonitis and tendon rupture warning in the labeling of all fluoroquinolone antibiotics and as a result, all these drugs now carry this warning, including gatifloxacin.

Gatifloxacin is a triumph of Bristol-Myers Squibb’s marketing department over science and the principles of good medical care. Over 3.2 million prescriptions were dispensed for the drug in 2001, after being on the market for only a few months.

What You Can Do

There is no medical reason for you to be taking gatifloxacin. There are numerous other, safer antibiotics approved to treat the same infections as this drug.