Avelox has been shown to prolong the QT interval of the electrocardiogram in some patients. The drug should be avoided in patients with known prolongation of the QT interval, patients with uncorrected hypokalemia and patients receiving class IA (e.g. quinidine, procainamide) or class III (e.g. amiodarone, sotalol) antiarrhythmic agents.

An additive effect of moxifloxacin and drugs that prolong the QT interval such as cisapride, erythromycin, antipsychotics, and tricyclic antidepressants cannot be excluded, therefore Avelox should be used with caution when given concurrently with these drugs.

Avelox should be used with caution in patients with ongoing proarrhythmic conditions, such as clinically significant bradycardia, acute myocardial ischemia.

As the magnitude of the QT prolongation may increase with increasing concentrations of the drug, the recommended dose (400 mg) should not be exceeded. QT prolongation may lead to an increased risk for ventricular arrhythmias including torsades de pointes. No cardiovascular morbidity or mortality attributable to QTc prolongation occurred with Avelox treatment in clinical studies with more than 9000 patients, however certain predisposing conditions may increase the risk for ventricular arrhythmias.

Seizures may occur with quinolone therapy. Avelox should be used with caution in patients with known or suspected CNS disorders which may predispose to seizures or lower the seizure threshold.

Due to limited clinical data, the use of Avelox is not recommended in patients with severe hepatic impairment (Child Pugh C).

Tendon inflammation and rupture may occur with quinolone therapy including Avelox, particularly in elderly patients and those treated concurrently with corticosteroids. At the first sign of pain or inflammation, patients should discontinue treatment and rest the affected limb(s).

Pseudomembranous colitis has been reported with the use of broad-spectrum antibiotics including Avelox; therefore it is important to consider this diagnosis in patients who develop serious diarrhea in association with the use of Avelox. In this clinical situation adequate therapeutic measures should be initiated immediately.

Quinlones have been shown to cause photosensitivity reactions in patients. However, in specially designed preclinical and clinical studies photosensitivity has not been observed with Avelox. In addition, since first marketed there has been no clinical evidence that Avelox causes photosensitivity reactions. Nevertheless, patients should be advised to avoid extensive exposure to either UV irradiation or sunlight.

In some instances, the hypersensitivity and allergic reactions already occurred after the first administration. In such a situation the doctor should be informed immediately.

Anaphylactic reactions in very rare instances can progress to a life threatening shock, in some instances after the first admini- stration. In these cases, Avelox has to be discontinued and medical treatment (e.g. for shock) is required.