Chelation Agents: Antacids, Sucralfate, Metal Cations, Multivitamins
LEVAQUIN® Tablets and Oral Solution
While the chelation by divalent cations is less marked than with other fluoroquinolones, concurrent administration of LEVAQUIN® Tablets and Oral Solution with antacids containing magnesium, or aluminum, as well as sucralfate, metal cations such as iron, and multivitamin preparations with zinc may interfere with the gastrointestinal absorption of levofloxacin, resulting in systemic levels considerably lower than desired. Tablets with antacids containing magnesium, aluminum, as well as sucralfate, metal cations such as iron, and multivitamin preparations with zinc or didanosine may substantially interfere with the gastrointestinal absorption of levofloxacin, resulting in systemic levels considerably lower than desired. These agents should be taken at least two hours before or two hours after oral LEVAQUIN® administration.
There are no data concerning an interaction of intravenous fluoroquinolones with oral antacids, sucralfate, multivitamins, didanosine, or metal cations. However, no fluoroquinolone should be co-administered with any solution containing multivalent cations, e.g., magnesium, through the same intravenous line [see Dosage and Administration].
No significant effect of LEVAQUIN® on the peak plasma concentrations, AUC, and other disposition parameters for R- and S- warfarin was detected in a clinical study involving healthy volunteers. Similarly, no apparent effect of warfarin on levofloxacin absorption and disposition was observed. However, there have been reports during the postmarketing experience in patients that LEVAQUIN® enhances the effects of warfarin. Elevations of the prothrombin time in the setting of concurrent warfarin and LEVAQUIN® use have been associated with episodes of bleeding. Prothrombin time, International Normalized Ratio (INR), or other suitable anticoagulation tests should be closely monitored if LEVAQUIN® is administered concomitantly with warfarin. Patients should also be monitored for evidence of bleeding [see Adverse Reactions
Patient Counseling Information].
Disturbances of blood glucose, including hyperglycemia and hypoglycemia, have been reported in patients treated concomitantly with fluoroquinolones and an antidiabetic agent. Therefore, careful monitoring of blood glucose is recommended when these agents are co-administered [see Warnings and Precautions
Patient Counseling Information].
Non-Steroidal Anti-Inflammatory Drugs
The concomitant administration of a non-steroidal anti-inflammatory drug with a fluoroquinolone, including LEVAQUIN®, may increase the risk of CNS stimulation and convulsive seizures [see Warnings and Precautions].
No significant effect of LEVAQUIN® on the plasma concentrations, AUC, and other disposition parameters for theophylline was detected in a clinical study involving healthy volunteers. Similarly, no apparent effect of theophylline on levofloxacin absorption and disposition was observed. However, concomitant administration of other fluoroquinolones with theophylline has resulted in prolonged elimination half-life, elevated serum theophylline levels, and a subsequent increase in the risk of theophylline-related adverse reactions in the patient population. Therefore, theophylline levels should be closely monitored and appropriate dosage adjustments made when LEVAQUIN® is co-administered. Adverse reactions, including seizures, may occur with or without an elevation in serum theophylline levels [see Warnings and Precautions].
No significant effect of LEVAQUIN® on the peak plasma concentrations, AUC, and other disposition parameters for cyclosporine was detected in a clinical study involving healthy volunteers. However, elevated serum levels of cyclosporine have been reported in the patient population when co-administered with some other fluoroquinolones. Levofloxacin Cmax and ke were slightly lower while Tmax and t½ were slightly longer in the presence of cyclosporine than those observed in other studies without concomitant medication. The differences, however, are not considered to be clinically significant. Therefore, no dosage adjustment is required for LEVAQUIN® or cyclosporine when administered concomitantly.
No significant effect of LEVAQUIN® on the peak plasma concentrations, AUC, and other disposition parameters for digoxin was detected in a clinical study involving healthy volunteers. Levofloxacin absorption and disposition kinetics were similar in the presence or absence of digoxin. Therefore, no dosage adjustment for LEVAQUIN® or digoxin is required when administered concomitantly.
Probenecid and Cimetidine
No significant effect of probenecid or cimetidine on the Cmax of levofloxacin was observed in a clinical study involving healthy volunteers. The AUC and t½ of levofloxacin were higher while CL/F and CLR were lower during concomitant treatment of LEVAQUIN® with probenecid or cimetidine compared to LEVAQUIN® alone. However, these changes do not warrant dosage adjustment for LEVAQUIN® when probenecid or cimetidine is co-administered.
Interactions with Laboratory or Diagnostic Testing
Some fluoroquinolones, including LEVAQUIN®, may produce false-positive urine screening results for opiates using commercially available immunoassay kits. Confirmation of positive opiate screens by more specific methods may be necessary.
In the event of an acute overdosage, the stomach should be emptied. The patient should be observed and appropriate hydration maintained. Levofloxacin is not efficiently removed by hemodialysis or peritoneal dialysis.
LEVAQUIN® exhibits a low potential for acute toxicity. Mice, rats, dogs and monkeys exhibited the following clinical signs after receiving a single high dose of LEVAQUIN®: ataxia, ptosis, decreased locomotor activity, dyspnea, prostration, tremors, and convulsions. Doses in excess of 1500 mg/kg orally and 250 mg/kg IV produced significant mortality in rodents.