Overdose
"In the event of acute overdose, the stomach should be emptied and adequate hydration maintained. ECG monitoring is recommended due to the possibility of QT interval prolongation. The patient should be carefully observed and given supportive treatment. The administration of activated charcoal as soon as possible after oral overdose may prevent excessive increase of systemic moxifloxacin exposure. About 3% and 9% of the dose of moxifloxacin, as well as about 2% and 4.5% of its glucuronide metabolite are removed by continuous ambulatory peritoneal dialysis and hemodialysis, respectively." (Quoting from 29 December 2008 package insert for Avelox)

Pharmacology
Mechanism of action
Moxifloxacin is a broad-spectrum antibiotic that is active against both Gram-positive and Gram-negative bacteria. It functions by inhibiting DNA gyrase, a type II topoisomerase, and topoisomerase IV, enzymes necessary to separate bacterial DNA, thereby inhibiting cell replication. Pharmacokinetics
About 52% of an oral or intravenous dose of moxifloxacin is metabolized via glucuronide and sulfate conjugation. The cytochrome P450 system is not involved in moxifloxacin metabolism, and is not affected by moxifloxacin. The sulfate conjugate (M1) accounts for around 38% of the dose, and is eliminated primarily in the feces. Approximately 14% of an oral or intravenous dose is converted to a glucuronide conjugate (M2), which is excreted exclusively in the urine.
Moxifloxacin should also be avoided in patients with uncorrected hypokalemia, or concurrent administration of other medications known to prolong the QT interval (antipsychotics and tricyclic antidepressants).Moxifloxacin should be used with caution in patients with diabetes, as glucose regulation may be significantly altered.Moxifloxacin is also considered to be contraindicated within the pediatric population, pregnancy, nursing mothers, patients with a history of tendon disorder, patients with documented QT prolongation, and patients with epilepsy or other seizure disorders. Coadministration of moxifloxacin with other drugs that also prolong the QT interval or induce bradycardia (e.g., beta-blockers, amiodarone) should be avoided. Careful consideration should be given in the use of moxifloxacin in patients with cardiovascular disease, including those with conduction abnormalities. Children and adolescents
The safety of moxifloxacin in human patients under age 18 has not been established. Animal studies suggest a risk of musculoskeletal harm in juveniles. Interactions
Moxifloxacin is not believed to be associated with clinically significant drug interactions due to inhibition or stimulation of hepatic metabolism. Thus, it should not, for the most part, require special clinical or laboratory monitoring to ensure its safety. Moxifloxacin has a potential for a serious drug interaction with NSAIDs.The combination of corticosteroids and moxifloxacin has increased potential to result in tendonitis and disability.Antacids containing aluminium or magnesium ions inhibit the absorption of moxifloxacin. Drugs that prolong the QT interval (e.g., pimozide) may have an additive effect on QT prolongation and lead to increased risk of ventricular arrhythmias. The international normalised ratio may be increased or decreased in patients treated with warfarin.