Gatifloxacin-induced hyperglycemia

Dysglycemia associated with quinolones

Antimicrobial therapy is well known to be associated with fluctuations of blood glucose levels. This review aims at exploring the association between glycemic fluctuations and antibiotics mainly focusing on quinolones. Quinolones are associated with hypoglycemia and hyperglycemia. Several mechanism are proposed to explain this causality.

Gatifloxacin-induced hyperglycemia: a case report and summary of the current literature

BACKGROUND

Gatifloxacin is a fluoroquinolone antibiotic that has been associated with severe hypoglycemic and hyperglycemic events.

OBJECTIVE

The purpose of this report was to describe a new case of gatifloxacin-associated hyperglycemia in an elderly patient and to provide a summary of case reports.

CASE SUMMARY

A male patient, aged 86 years, was hospitalized with small bowel obstruction due to adhesions from a previous appendectomy. At the time of admission, the patient weighed 78.5 kg (ideal body weight, 73 kg), had a body mass index of 24.8 kg/m2, and had a calculated creatinine clearance of 45.6 mL/min. The patient's hospital medications were metoprolol, diltiazem, subcutaneous heparin, ranitidine, vancomycin, piperacillin/tazobactam, and aspirin. He also was treated with gatifloxacin 400 mg QD for suspected pneumonia during the hospital stay. After 4 days of the gatifloxacin regimen, the patient's mean blood glucose concentration increased from 133 mg/dL at the time of admission to 537 mg/dL. Although the patient exhibited signs of glycosuria (ie, urine glucose concentration >1000 mg/dL), he did not complain of symptoms of hyperglycemia, such as polyuria, polyphagia, or polydipsia. The hyperglycemia resolved after administration of gatifloxacin was discontinued and the patient had received regular insulin 15 U SC over 5 hours.

DISCUSSION

The exact mechanism by which gatifloxacin induces hyperglycemia is unknown, but it may be related to vacuolation of pancreatic beta-cells, leading to a decrease in insulin secretion. This case, along with the 15 other summarized cases, adds to the evidence for an association between gatifloxacin and hyperglycemia. These patients had other risk factors that may have contributed to the development of hyperglycemia, including age >65 years and renal impairment.

CONCLUSION

An elderly patient with no history of diabetes developed severe hyperglycemia after receiving doses of gatifloxacin 400 mg that had not been adjusted for age-related renal impairment. The hyperglycemia resolved after discontinuation of gatifloxacin.

Gatifloxacin-Induced Hyperglycemia: A Review of 4 Cases and the Literature

Gatifloxacin, a broad-spectrum fluoroquinolone, has recently been voluntarily withdrawn by Bristol-Myers Squibb from the market secondary to dysglycemic events associated with this agent. Risk factors for this adverse event include diabetes and those who are elderly (65 years of age or older), have renal insufficiency, or take glucose altering medications. The mechanism for this adverse reaction is not fully understood. However, it is theorized that there is an association between accumulation of gatifloxacin (particularly in elderly patients or those with renal insufficiency) and dysglycemic events with gatifloxacin. A review of the literature found 13 reported cases of hyperglycemia induced by gatifloxacin and 2 clinical trials evaluating gatifloxacin's association with hyperglycemia. Similarly to other reported cases, the authors' 4 outpatients were initiated on gatifloxacin therapy and subsequently had developed hyperglycemia during gatifloxacin therapy. Prior to the multiple observations of dysglycemias associated with gatifloxacin, this medication was widely used and thought to have an excellent safety profile. Hence, clinicians should be vigilant and exercise caution with newly approved medications.

Gatifloxacin-induced dysglycemia

PURPOSE

The development of gatifloxacin-induced dysglycemia in 13 patients is described; the details of the 3 most severe cases are presented.

SUMMARY

Three elderly patients developed dysglycemia after initiation of gatifloxacin therapy. Both patients who developed hypoglycemia were receiving concomitant insulin or oral antidiabetic agents. Repeated doses of dextrose were required for management. The Naranjo et al. probability rating scale revealed that gatifloxacin was the probable cause in the majority of the 13 cases, primarily because of the temporal relationship with gatifloxacin and, in some instances, resolution of dysglycemia after drug discontinuation. Although the mechanism of gatifloxacin-induced hyperglycemia is not known, in vitro studies have found that certain quinolone antimicrobials can lower serum glucose levels by blocking adenosine 5'-triphosphate-dependent potassium channels in the pancreatic beta-cell, stimulating insulin release. It is difficult to unequivocally implicate gatifloxacin as the only cause of dysglycemia in the cases presented, as there are many explanations for poor glycemic control in hospitalized patients, such as stress, infection, decreased renal function, and concomitant drug therapies. However, the patients' medication regimens appeared to be stable before gatifloxacin administration.

CONCLUSION

Thirteen patients developed dysglycemia after receiving gatifloxacin. Gatifloxacin was found to be the probable cause in the majority of cases.

Levofloxacin 750-mg for 5 days for the treatment of hospitalized Fine Risk Class III/IV community-acquired pneumonia patients

BACKGROUND

The efficacy and safety of 750-mg, 5-day levofloxacin was recently shown to be comparable to 500-mg, 10-day levofloxacin in a randomized, double-blind, multicentre clinical trial for mild-to-severe community-acquired pneumonia (CAP). This subgroup analysis attempted to compare the safety and efficacy of a short-course levofloxacin regimen with traditional levofloxacin dosing for PSI Class III/IV patients.

METHODS

This retrospective, subgroup analysis focused on Pneumonia Severity Index Class III and IV patients enrolled in the study. Measurements included clinical and microbiological success rates, adverse events, and symptom resolution by day 3 of therapy.

RESULTS

Of the 528 patients in the ITT population, 219 (41.5%) were categorized as PSI Class III/IV and included in this analysis. Among the clinically evaluable patients, 90.8% (69/76) of patients treated with the 750-mg regimen achieved clinical success, compared with 85.5% (71/83) treated with 500-mg levofloxacin (95% CI,-15.9 to 5.4). Eradication rates in the microbiologically evaluable population were comparable for the 750- and 500-mg regimens (88.9% vs 87.5%, respectively; 95% CI,-18.3 to 15.6). Both regimens were well tolerated and had comparable safety profiles. A greater proportion of patients in the 750-mg treatment group experienced resolution of fever (48.4% vs 34.0%; P=.046) and purulent sputum (48.4% vs 27.5%; P=.007) by day 3 of therapy.

CONCLUSIONS

The 750-mg, 5-day levofloxacin course achieved comparable clinical and microbiologic efficacy to the 500-mg, 10-day regimen. By day 3 of therapy, a greater proportion of patients in the 750-mg group had objective and subjective resolution of fever. Further research is needed to determine the economic significance of short-course levofloxacin therapy.

Comparison of the adverse event profiles of levofloxacin 500 mg and 750 mg in clinical trials for the treatment of respiratory infections

OBJECTIVE

To compare safety data with levofloxacin 500 mg and 750 mg from clinical trials for the treatment of respiratory infections.

METHODS

We compared adverse event data for levofloxacin 500 mg and 750 mg from clinical trials in acute bacterial sinusitis, acute bacterial exacerbation of chronic bronchitis, and community-acquired pneumonia. Adverse events occurring after the initiation of therapy were classified as treatment-emergent adverse events (TEAE); drug-related adverse events (DRAE) were TEAE assessed by the clinical investigator as definitely/very likely or probably related to levofloxacin therapy.

RESULTS

Overall, the safety profile of the two doses was similar but not identical. TEAE occurred in 49.0% (1601/3268) of those treated with 500 mg and in 45.5% (519/1141) of those treated with 750 mg (p = 0.042); the corresponding rates of DRAE were 7.6% (248/3268) and 8.0% (91/1141) (p = 0.699). There was no statistically significant difference in terms of overall TEAE and DRAE rates within each of the three infectious conditions, but there were in specific events, all of which are expected with levofloxacin therapy. The limitations of this analysis include that it utilized a subset of available safety data, that it includes data only from clinical trials, and that we report primarily on events occurring in > or = 2% of patients.

CONCLUSIONS

Given similar adverse event profiles and the advantages of higher dose therapy, including shorter courses of therapy and potential impact on preventing resistance, clinicians should consider utilizing the 750 mg dose of levofloxacin when choosing between dosage strengths for treatment of indicated infections.

Outpatient gatifloxacin therapy and dysglycemia in older adults

BACKGROUND

Gatifloxacin has been associated with both hypoglycemia and hyperglycemia. We examined dysglycemia-related health outcomes associated with various antibiotics in a population of approximately 1.4 million Ontario, Canada, residents 66 years of age or older.

METHODS

We conducted two population-based, nested case-control studies. In the first, case patients were persons treated in the hospital for hypoglycemia after outpatient treatment with a macrolide, a second-generation cephalosporin, or a respiratory fluoroquinolone (gatifloxacin, levofloxacin, moxifloxacin, or ciprofloxacin). In the second, case patients were persons who received hospital care for hyperglycemia. For each case patient, we identified up to five controls matched according to age, sex, the presence or absence of diabetes, and the timing of antibiotic therapy.

RESULTS

Between April 2002 and March 2004, we identified 788 patients treated for hypoglycemia within 30 days after antibiotic therapy. As compared with macrolide antibiotics, gatifloxacin was associated with an increased risk of hypoglycemia (adjusted odds ratio, 4.3; 95 percent confidence interval, 2.9 to 6.3). Levofloxacin was also associated with a slightly increased risk (adjusted odds ratio, 1.5; 95 percent confidence interval, 1.2 to 2.0), but no such risk was seen with moxifloxacin, ciprofloxacin, or cephalosporins. We then identified 470 patients treated for hyperglycemia within 30 days after antibiotic therapy. As compared with macrolides, gatifloxacin was associated with a considerably increased risk of hyperglycemia (adjusted odds ratio, 16.7; 95 percent confidence interval, 10.4 to 26.8), but no risk was noted with the other antibiotics. Risks were similar in the two studies regardless of the presence or absence of diabetes.

CONCLUSIONS

As compared with the use of other broad-spectrum oral antibiotics, including other fluoroquinolones, the use of gatifloxacin among outpatients is associated with an increased risk of in-hospital treatment for both hypoglycemia and hyperglycemia.

A retrospective, comparative evaluation of dysglycemias in hospitalized patients receiving gatifloxacin, levofloxacin, ciprofloxacin, or ceftriaxone

STUDY OBJECTIVES

To compare rates of blood glucose abnormalities in hospitalized patients receiving fluoroquinolones or ceftriaxone, and to describe the characteristics of patients who develop blood glucose abnormalities while receiving these agents.

DESIGN

Retrospective chart review.

SETTING

Two community-based hospitals in the Houston, Texas, region.

PATIENTS

Seventeen thousand one hundred eight patients who received fluoroquinolones or ceftriaxone; of those, 101 received levofloxacin, gatifloxacin, or ceftriaxone and also had serum glucose concentrations above 200 or below 50 mg/dl within 72 hours of receiving the drug.

MEASUREMENTS AND MAIN RESULTS

Baseline demographics of patients with glucose abnormalities while receiving gatifloxacin, levofloxacin, or ceftriaxone were similar. Mean +/- SD patient age, weight, and estimated creatinine clearance were 67 +/- 17 years, 79 +/- 21 kg, and 52 +/- 32 ml/minute, respectively. Dysglycemia rates relative to treatment were as follows: gatifloxacin 76 (1.01%) of 7540 patients, levofloxacin 11 (0.93%) of 1179, ceftriaxone 14 (0.18%) of 7844, ciprofloxacin 0 (0%) of 545, and any fluoroquinolone 87 (0.94%) of 9264. Dysglycemia was more likely to occur in patients receiving any fluoroquinolone than in those receiving ceftriaxone (relative risk [RR] 3.32, 95% confidence interval (CI) 2.31-4.78, p < 0.05). The rate of dysglycemia did not differ with gatifloxacin and levofloxacin (RR 1.07, 95% CI 0.62-1.86, p = 0.8). Of the 101 patients with dysglycemias, hypoglycemia occurred in nine (9%) and hyperglycemia in 92 (91%). In a multivariate analysis of patients receiving fluoroquinolones, only concomitant sulfonylurea therapy was identified as an independent risk factor for development of hypoglycemia compared with patients who experienced hyperglycemia.

CONCLUSION

In the 17,108 patients receiving a fluoroquinolone or ceftriaxone, the rate of dysglycemia was greater in those receiving levofloxacin or gatifloxacin than in those receiving ceftriaxone. However, no difference was noted in the rate of glucose abnormalities with levofloxacin versus gatifloxacin. Clinicians should be aware of dysglycemic events that may occur in patients receiving fluoroquinolones, especially in those with diabetes mellitus or those receiving sulfonylureas.

Effects of Gatifloxacin on Serum Glucose Concentration in Normal and Diabetic Rats

To clarify the mechanisms of gatifloxacin (GFLX)-induced hypoglycemia and hyperglycemia, the effect of GFLX on serum glucose levels was investigated in normal and diabetic rats. Rats received an intravenous injection of GFLX and their arterial blood was sampled periodically. Diabetic rats were produced by the intraperitoneal injection of streptozotocin and nicotinamide. In normal rats, the serum glucose concentration was decreased by GFLX at 25 and 50 mg/kg, while it was elevated 0.25 h after the injection of 100 mg/kg of GFLX. Serum immunoreactive insulin (IRI) levels increased as the dose of GFLX increased. The serum epinephrine concentration rose rapidly after the injection of GFLX at 50 and 100 mg/kg. In diabetic rats, the serum glucose concentration was actually increased by GFLX at 50 mg/kg. The baseline concentration of IRI was lower and the degree of the elevation caused by GFLX was smaller in diabetic rats. Both diabetic and control rats showed an increase in the serum epinephrine concentration after the injection of 50 mg/kg of GFLX. In conclusion, GFLX-induced secretion of insulin and epinephrine would contribute to the abnormalities in glucose homeostasis. The response of serum glucose to GFLX may differ between diabetic and normal rats due to the alteration of insulin secretion.

Glucose Homeostasis Abnormalities Associated with Use of Gatifloxacin

BACKGROUND

More than 20 published case reports have described an association between the use of gatifloxacin and hypoglycemia or hyperglycemia. We compare the rates of glucose homeostasis abnormality (GHA) adverse event reports (AERs) associated with the use of gatifloxacin and comparator quinolones.

METHODS

We obtained spontaneous AERs associated with the use of ciprofloxacin, gatifloxacin, levofloxacin, and moxifloxacin from the US Food and Drug Administration that were reported between November 1997 and September 2003. We removed duplicate and foreign cases. We used specific coding terms to identify GHA AERs. We calculated GHA AER rates, using either the total number of AERs or estimated retail prescriptions as denominators.

RESULTS

The use of ciprofloxacin, gatifloxacin, levofloxacin, and moxifloxacin was associated with 10,025 unique AERs in the United States, including 568 GHA AERs, 25 of which had fatality. Use of gatifloxacin was associated with 453 GHA AERs (80%) and 17 GHA AERs with fatality (68%). GHA AERs comprised 24% of all AERs associated with gatifloxacin, compared with ciprofloxacin (1.3%), levofloxacin (1.6%), and moxifloxacin (1.3%) (P<.0001 for each comparison). Use of gatifloxacin was associated with 477 GHA AERs per 10(7) retail prescriptions, compared with ciprofloxacin (4 GHA AERs), levofloxacin (11 GHA AERs), and moxifloxacin (39 GHA AERs) (P<.0001 for each comparison). Patients with GHA AERs were older and more likely to be receiving concomitant treatment for diabetes. Limitations of the study include the use of spontaneous adverse event reporting, which is incomplete and potentially biased. This analysis cannot be used alone to demonstrate causality.

CONCLUSIONS

Use of gatifloxacin is associated with a much higher rate of GHA AERs than are comparator quinolones. This analysis is consistent with the results of in vitro analyses, animal studies, human volunteer studies, case reports, and a large randomized trial. Alternatives to gatifloxacin should be used in patients with diabetes.

Safety of Newer Parenteral Antibiotics

Several parenteral antimicrobials have been introduced into clinical practice over the course of the last decade. Some of these agents (e.g., linezolid, daptomycin, and tigecycline) are prototypes of new classes of compounds. In comparative clinical trials, these newer anti-infectives have been shown to be safe and to have low rates of discontinuation by patients. However, long-term use has revealed unique toxicities associated with the use of some of these drugs. The adverse events and potential drug interactions associated with the use of these antibiotics are variable and require familiarity with the safety profile of each drug. It is especially important that clinicians be able to recognize serious adverse events associated with the use of specific drugs, because most of the adverse events can be readily reversed by cessation of therapy.

Severe Hyperglycemia During Renally Adjusted Gatifloxacin Therapy

OBJECTIVE

To report a case of severe hyperglycemia in a nondiabetic patient receiving gatifloxacin that was properly dosed based on renal function.

CASE SUMMARY

A 65-year-old nondiabetic female with progressive renal dysfunction was admitted for severe hyperglycemia. The patient had received 9 days of a 10-day course of renally adjusted therapy with gatifloxacin 200 mg/day for bronchitis. Her blood glucose level on admission was 1121 mg/dL, at which point the gatifloxacin was discontinued. After several days of intensive insulin therapy, the blood glucose levels returned to normal, and the patient was subsequently discharged.

DISCUSSION

Gatifloxacin-induced hyperglycemia has been reported in the literature, but based on a MEDLINE search (1966–December 2004), no such cases were found in a nondiabetic patient receiving the proper gatifloxacin dose, adjusted for degree of renal insufficiency. The available case reports seem to suggest the increase in blood glucose concentrations could have been precipitated by high drug concentrations in patients not receiving the renally adjusted dose or in those with preexisting, undiagnosed diabetes. A definite mechanism of action for gatifloxacin-induced hyperglycemia is not known. The Naranjo probability scale revealed a probable adverse reaction of hyperglycemia associated with gatifloxacin therapy.

CONCLUSIONS

Healthcare professionals should be more aware of the possible development of hyperglycemia in all patients taking gatifloxacin, including those who are not diabetic and those receiving appropriately reduced doses for renal dysfunction.

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