Floxsafe/Floxsafe IV Drug Interactions

Floxsafe: Interactions with medicinal products: An additive effect on QT interval prolongation of moxifloxacin and other medicinal products that may prolong the QTc interval cannot be excluded. This might lead to an increased risk of ventricular arrhythmias, including torsade de pointes. Therefore, coadministration of moxifloxacin with any of the following medicinal products is contraindicated: anti-arrhythmics class IA (e.g. quinidine, hydroquinidine, disopyramide); anti-arrhythmics class III (e.g. amiodarone, sotalol, dofetilide, ibutilide); antipsychotics (e.g. phenothiazines, pimozide, sertindole, haloperidol, sultopride); tricyclic antidepressive agents; certain antimicrobial agents (saquinavir, sparfloxacin, erythromycin IV, pentamidine, antimalarials particularly halofantrine) certain antihistaminics (terfenadine, astemizole, mizolastine); others (cisapride, vincamine IV, bepridil, diphemanil).
Moxifloxacin should be used with caution in patients who are taking medication that can reduce potassium levels (e.g. loop and thiazide type diuretics, laxatives and enemas [high doses], corticosteroids, amphotericin B) or medication that is associated with clinically significant bradycardia.
An interval of about 6 hours should be left between administration of agents containing bivalent or trivalent cations (e.g. antacids containing magnesium or aluminium, didanosine tablets, sucralfate and agents containing iron or zinc) and administration of moxifloxacin.
Concomitant administration of charcoal with an oral dose of 400 mg moxifloxacin led to a pronounced prevention of drug absorption and a reduced systemic availability of the drug by more than 80%. Therefore, the concomitant use of these two drugs is not recommended (except for overdose cases).
After repeated dosing in healthy volunteers, moxifloxacin increased C_max of digoxin by approximately 30% without affecting AUC or trough levels. No precaution is required for use with digoxin.
In studies conducted in diabetic volunteers, concomitant administration of oral moxifloxacin with glibenclamide resulted in a decrease of approximately 21% in the peak plasma concentrations of glibenclamide. The combination of glibenclamide and moxifloxacin could theoretically result in a mild and transient hyperglycaemia. However, the observed pharmacokinetic changes for glibenclamide did not result in changes of the pharmacodynamic parameters (blood glucose, insulin). Therefore no clinically relevant interaction was observed between moxifloxacin and glibenclamide.
Changes in INR: A large number of cases showing an increase in oral anticoagulant activity have been reported in patients receiving antibacterial agents, especially fluoroquinolones, macrolides, tetracyclines, cotrimoxazole and some cephalosporins. The infectious and inflammatory conditions, age and general status of the patient appear to be risk factors. Under these circumstances, it is difficult to evaluate whether the infection or the treatment caused the INR (international normalised ratio) disorder. A precautionary measure would be to more frequently monitor the INR. If necessary, the oral anticoagulant dosage should be adjusted as appropriate.
Clinical studies have shown no interactions following concomitant administration of moxifloxacin with: ranitidine, probenecid, oral contraceptives, calcium supplements, morphine administered parenterally, theophylline, cyclosporine or itraconazole.
In vitro studies with human cytochrome P450 enzymes supported these findings. Considering these results a metabolic interaction via cytochrome P450 enzymes is unlikely.
Interaction with food: Moxifloxacin has no clinically relevant interaction with food including dairy products.
Floxsafe IV: Warfarin/Changes in INR (International Normalized Ratio): Antibacterial agents, including moxifloxacin, have been reported to enhance the anticoagulant effects of warfarin or its derivatives in the patients population. Infectious disease (accompanying inflammatory process), age and general status of the patient are risk factors. Although an interaction between moxifloxacin and warfain has not been demonstrated in clinical trials, INR should be monitored and, if necessary, the oral anticoagulant dosage should be adjusted as appropriate.
No interaction has occurred following concomitant oral administration of moxifloxacin with digoxin, ranitidine, glibenclamide (antidiabetics), morphine, probenecid, or oral contraceptives.
Theophylline: In accordance with in vitro data, moxifloxacin did not affect the pharmacokinetics of theophylline pharmacokinetics (and vice versa) and moxifloxacin does not interfere with the CYP1A2 isoenzyme.
Itraconazole: When moxifloxacin were administered concomitantly with itraconazole, the AUC of itraconazole was changed a little. Pharmacokinetics of moxifloxacin was not significantly altered by the administration of itraconazole. Therefore, no dose adjustment is necessary for itraconazole when given with moxifloxacin and vice versa.
Atenolol: The pharmacokinetics of atenolol is not significantly altered by moxifloxacin. AUC of atenolol was increased by approximately 4% and Cmax of atenolol was decreased by 10% following co-administration with a single dose of moxifloxacin to healthy volunteers.
Thiazide-diuretics, loop-diuretics, corticosteroids, ACTH, glycyrrhizin: These have an effect of potassium excretion, therefore, these can cause a hypokalemia. Ventricular tachyarrhythmias (including torsades de pointes) or QT prolongation may occur when moxifloxacin is administered to the patients with hypokalemia.
Nonsteroidal anti-inflammatory drugs of phenylacetic acid or propionic acid derivatives (ex. roxoprofen, etc.): The concomitant administration of a nonsteroidal anti-inflammatory drug with moxifloxacin may cause convulsions as inhibiting GABA receptor of CNS.