Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness. Frequencies are defined as: common (≥ 1/100 to < 1/10), uncommon (≥ 1/1,000 to < 1/100), rare (≥ 1/10,000 to < 1/1,000), very rare (< 1/10,000). (See Table 7.)

The following undesirable effects have a higher frequency in the subgroup of IV/oral sequentially treated patients: Common: Increased gamma-glutamyl-transferase.
Uncommon: Ventricular tachyarrhythmias, Hypotension, Edema, Antibiotic associated colitis (in very rare cases associated with life threatening complications), Seizures of various clinical manifestations (incl. grand mal convulsions), Hallucination, Renal impairment and renal failure (due to dehydration esp. in elderly with pre- existing renal disorders).
There have been very rare cases of the following side effects reported following treatment with other fluoroquinolones, which might possibly also occur during treatment with moxifloxacin: hypernatraemia, hypercalcaemia, haemolytic anaemia, rhabdomyolysis, photosensitivity reactions.