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Side Effects


Serious and Otherwise Important Adverse Reactions

The following serious and otherwise important adverse reactions are discussed in greater detail in the WARNINGS AND PRECAUTIONS section of the label:

Clinical Trial Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The data described below reflect exposure to AVELOX in 14981 patients in 71 active controlled Phase II-IV clinical trials in different indications [see INDICATIONS AND USAGE]. The population studied had a mean age of 50 years (approximately 73% of the population was <65 years of age), 50% were male, 63% were Caucasian, 12% were Asian and 9% were Black. Patients received AVELOX 400 mg once daily PO, IV, or sequentially (IV followed by PO). Treatment duration was usually 6-10 days, and the mean number of days on therapy was 9 days.

Discontinuation of AVELOX due to adverse events occurred in 5.0% of patients overall, 4.1% of patients treated with 400 mg PO, 3.9% with 400 mg IV and 8.2% with sequential therapy 400 mg PO/IV. The most common adverse events leading to discontinuation with the 400 mg PO doses were nausea (0.8%), diarrhea (0.5%), dizziness (0.5%), and vomiting (0.4%). The most common adverse event leading to discontinuation with the 400 mg IV dose was rash (0.5%). The most common adverse events leading to discontinuation with the 400 mg IV/PO sequential dose were diarrhea (0.5%), pyrexia (0.4%).

Adverse reactions occurring in ≥1% of AVELOX-treated patients and less common adverse reactions, occurring in 0.1 to <1% of AVELOX-treated patients, are shown in Tables 2 and Table 3, respectively. The most common adverse drug reactions (≥3%) are nausea, diarrhea, headache, and dizziness.

Table 2 : Common (≥ 1.0%) Adverse Reactions Reported in Active-Controlled Clinical Trials with AVELOX

System Organ Class Adverse Reactionsa %
Blood and Lymphatic System Disorders Anemia 1.1
Gastrointestinal Disorders Nausea 6.9
Diarrhea 6.0
Vomiting 2.4
Constipation 1.9
Abdominal pain 1.5
Abdominal pain upper 1.1
Dyspepsia 1.0
General Disorders and Administration Site Conditions Pyrexia 1.1
Investigations Alanine aminotransferase increased 1.1
Metabolism and Nutritional Disorder Hypokalemia 1
Nervous System Disorders Headache 4.2
Dizziness 3.0
Psychiatric Disorders Insomnia 1.9
a MedDRA Version 12.0

Table 3 : Less Common (0.1 to <1.0%) Adverse Reactions Reported in Active-Controlled Clinical Trials with AVELOX (N=14,981)

System Organ Class Adverse Reactionsa
Blood and Lymphatic System Disorders Thrombocythemia
Cardiac Disorders Atrial fibrillation Palpitations Tachycardia Cardiac failure congestive Angina pectoris Cardiac failure Cardiac arrest Bradycardia
Ear and Labyrinth Disorders Vertigo
Eye Disorders Vision blurred
Gastrointestinal Disorders Dry mouth
Abdominal discomfort
Abdominal distention
Gastroesophageal reflux disease
General Disorders and Administration Site Conditions Fatigue
Chest pain
Edema peripheral
Infusion site extravasation
Chest discomfort
Facial pain
Hepatobiliary disorders Hepatic function abnormal
Infections and Infestations Vulvovaginal candidiasis
Oral candidiasis
Vulvovaginal mycotic infection
Vaginal infection
Oral fungal infection
Fungal infection
Investigations Aspartate aminotransferase increased
Gamma-glutamyltransferase increased
Blood alkaline phosphatase increased
Hepatic enzyme increased
Electrocardiogram QT prolonged
Blood lactate dehydrogenase increased
Platelet count increased
Blood amylase increased
Blood glucose increased
Lipase increased
Hemoglobin decreased
Blood creatinine increased
Transaminases increased
White blood cell count increased
Blood urea increased
Liver function test abnormal
Hematocrit decreased
Prothrombin time prolonged
Eosinophil count increased
Activated partial thromboplastin time prolonged
Blood bilirubin increased
Blood triglycerides increased
Blood uric acid increased
Blood pressure increased
Metabolism and Nutrition Disorders Hyperglycemia
Decreased appetite
Musculoskeletal and Connective Tissue Disorders Back pain
Pain in extremity
Muscle spasms
Musculoskeletal chest pain
Musculoskeletal pain
Nervous System Disorders Dysgeusia
Tension headache
Psychiatric Disorders Anxiety
Confusional state
Renal and Urinary Disorders Renal failure
Renal failure acute
Reproductive System and Breast Disorders Vulvovaginal pruritus
Respiratory, Thoracic, and Mediastinal Disorders Dyspnea
Skin and Subcutaneous Tissue Disorders Rash
Dermatitis allergic
Night sweats
Vascular disorders Hypertension
a MedDRA Version 12.0

Laboratory Changes

Changes in laboratory parameters, without regard to drug relationship, which are not listed above and which occurred in ≥ 2% of patients and at an incidence greater than in controls included: increases in MCH, neutrophils, WBCs, PT ratio, ionized calcium, chloride, albumin, globulin, bilirubin; decreases in hemoglobin, RBCs, neutrophils, eosinophils, basophils, PT ratio, glucose, pO2, bilirubin, and amylase. It cannot be determined if any of the above laboratory abnormalities were caused by the drug or the underlying condition being treated.

Postmarketing Experience

Table 4 lists adverse reactions that have been identified during post-approval use of AVELOX. Because these events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Table 4: Postmarketing Reports of Adverse Drug Reactions

System/Organ Class Adverse Reaction
Blood and Lymphatic System Disorders Agranulocytosis Pancytopenia [see WARNINGS AND PRECAUTIONS]
Cardiac Disorders Ventricular tachyarrhythmias (including in very rare cases cardiac arrest and torsade de pointes, and usually in patients with concurrent severe underlying proarrhythmic conditions)
Ear and Labyrinth Disorders Hearing impairment, including deafness (reversible in majority of cases)
Eye Disorders Vision loss (especially in the course of CNS reactions, transient in majority of cases)
Hepatobiliary Disorders Hepatitis (predominantly cholestatic) Hepatic failure (including fatal cases) Jaundice Acute hepatic necrosis [see WARNINGS AND PRECAUTIONS]
Immune System Disorders Anaphylactic reaction Anaphylactic shock Angioedema (including laryngeal edema) [see WARNINGS AND PRECAUTIONS]
Musculoskeletal and Connective Tissue Disorders Tendon rupture [see WARNINGS AND PRECAUTIONS]
Nervous System Disorders Altered coordination Abnormal gait [see WARNINGS AND PRECAUTIONS] Myasthenia gravis (exacerbation of) [see WARNINGS AND PRECAUTIONS] Muscle weakness Peripheral neuropathy (that may be irreversible), polyneuropathy [see WARNINGS AND PRECAUTIONS]
Psychiatric Disorders Psychotic reaction (very rarely culminating in self-injurious behavior, such as suicidal ideation/thoughts or suicide attempts [see WARNINGS AND PRECAUTIONS]
Renal and Urinary Disorders Renal dysfunction Interstitial nephritis [see WARNINGS AND PRECAUTIONS]
Respiratory, Thoracic and Mediastinal Disorders Allergic pneumonitis [see WARNINGS AND PRECAUTIONS]
Skin and Subcutaneous Tissue Disorders Photosensitivity/phototoxicity reaction [see WARNINGS AND PRECAUTIONS] Stevens-Johnson syndrome Toxic epidermal necrolysis [see WARNINGS AND PRECAUTIONS]

Read the Avelox (moxifloxacin hcl) Side Effects Center for a complete guide to possible side effects


Antacids, Sucralfate, Multivitamins and other products containing Multivalent Cations

Quinolones form chelates with alkaline earth and transition metal cations. Oral administration of quinolones with antacids containing aluminum or magnesium, with sucralfate, with metal cations such as iron, or with multivitamins containing iron or zinc, or with formulations containing divalent and trivalent cations such as VIDEX® (didanosine) chewable/buffered tablets or the pediatric powder for oral solution, may substantially interfere with the absorption of quinolones, resulting in systemic concentrations considerably lower than desired. Therefore, AVELOX should be taken at least 4 hours before or 8 hours after these agents. [see DOSAGE AND ADMINISTRATION, Pharmacokinetics, and PATIENT INFORMATION]


Quinolones, including AVELOX, have been reported to enhance the anticoagulant effects of warfarin or its derivatives in the patient population. In addition, infectious disease and its accompanying inflammatory process, age, and general status of the patient are risk factors for increased anticoagulant activity. Therefore the prothrombin time, International Normalized Ratio (INR), or other suitable anticoagulation tests should be closely monitored if a quinolone is administered concomitantly with warfarin or its derivatives. [see ADVERSE REACTIONS, Pharmacokinetics, and PATIENT INFORMATION]

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

Although not observed with AVELOX in preclinical and clinical trials, the concomitant administration of a nonsteroidal anti-inflammatory drug with a quinolone may increase the risks of CNS stimulation and convulsions [see WARNINGS AND PRECAUTIONS, and PATIENT INFORMATION].

Drugs that Prolong QT

There is limited information available on the potential for a pharmacodynamic interaction in humans between AVELOX and other drugs that prolong the QTc interval of the electrocardiogram. Sotalol, a Class III antiarrhythmic, has been shown to further increase the QTc interval when combined with high doses of intravenous (IV) AVELOX in dogs. Therefore, AVELOX should be avoided with Class IA and Class III antiarrhythmics. [see WARNINGS AND PRECAUTIONS, Nonclinical Toxicology, and PATIENT INFORMATION]

Read the Avelox Drug Interactions Center for a complete guide to possible interactions

Last reviewed on RxList: 8/29/2013
This monograph has been modified to include the generic and brand name in many instances.

Side Effects

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