In clinical trials, the following events were considered likely to be drug-related in patients receiving levofloxacin: nausea 1.2%, diarrhea 1.0%, vaginitis 0.6%, insomnia 0.4%, abdominal pain 0.4%, flatulence 0.3%, pruritus 0.3%, dizziness 0.3%, rash 0.3%, dyspepsia 0.2%, genital moniliasis 0.2%, moniliasis 0.2%, taste perversion 0.2%, vomiting 0.2%, injection site pain 0.2%, injection site reaction 0.2%, injection site inflammation 0.1%, constipation 0.1%, fungal infection 0.1%, genital pruritus 0.1%, headache 0.1%, nervousness 0.1%, rash erythematous 0.1%, urticaria 0.1%, anorexia 0.1%, somnolence 0.1%, agitation 0.1%, rash maculo-papular 0.1%, tremor 0.1%, condition aggravated 0.1%, allergic reaction 0.1%.
In clinical trials, the following events occurred in >3% of patients, regardless of drug relationship: nausea 7.1%, headache 6.2%, diarrhea 5.5%, insomnia 5.1%, constipation 3.5%.
In clinical trials, the following events occurred in 1 to 3% of patients, regardless of drug relationship: abdominal pain 2.7%, dizziness 2.5%, vomiting 2.5%, dyspepsia 2.3%, vaginitis 1.7%, rash 1.6%, chest pain 1.4%, pruritus 1.3%, sinusitis 1.3%, dyspnea 1.4%, fatigue 1.4%, flatulence 1.2%, pain 1.6%, back pain 1.2%, rhinitis 1.2%, anxiety 1.2%, pharyngitis 1.2%.
In clinical trials, the following events, of potential medical importance, occurred at a rate of 0.1% to 0.9%, regardless of drug relationship: See Table 19.

In clinical trials using multiple-dose therapy, ophthalmologic abnormalities, including cataracts and multiple punctate lenticular opacities, have been noted in patients undergoing treatment with other quinolones. The relationship of the drugs to these events is not presently established.
Crystalluria and cylindruria have been reported with other quinolones.
The following markedly abnormal laboratory values appeared in >2% of patients receiving levofloxacin. It is not known whether these abnormalities were caused by the drug or the underlying condition being treated.
Blood Chemistry: decreased glucose (2.2%), CPK increased.
Hematology: decreased lymphocytes (2.2%).
Undesirable effects: Cardiac disorders: Frequency not known: ventricular arrhythmia and torsades de pointes (reported predominantly in patients with risk factors for QT prolongation), ECG QT prolonged.
Post-Marketing Adverse Reactions: Additional adverse events reported from worldwide post-marketing experience with levofloxacin include: allergic pneumonitis, anaphylactic shock, anaphylactoid reaction, dysphonia, abnormal EEG, encephalopathy, eosinophilia, erythema multiforme, hemolytic anemia, multi-system organ failure, increased International Normalized Ratio (INR)/prothrombin time, Stevens-Johnson Syndrome, tendon rupture, torsades de pointes, vasodilation peripheral nerve disorder, extrapyramidal disorder, hearing losses, hepatitis fulminant, hyperhidrosis, rhabdomyolysis, muscle injury including rupture, pollakiuria, interstitial nephritis, leukopenia, pancytopenia, pseudomembranous colitis, photosensitivity, paranoia.
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