December 1, 2015
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Side Effects


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

Clinical Trials 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 less than 65 years of age), 50% were male, 63% were Caucasian, 12% were Asian and 9% were Black. Patients received AVELOX 400 mg once daily oral, intravenous, or sequentially (intravenous followed by oral). Treatment duration was usually 6 to 10 days, and the mean number of days on therapy was 9 days.

Discontinuation of AVELOX due to adverse reactions occurred in 5% of patients overall, 4% of patients treated with 400 mg PO, 4% with 400 mg intravenous and 8% with sequential therapy 400 mg oral/intravenous. The most common adverse reactions ( > 0.3%) leading to discontinuation with the 400 mg oral doses were nausea, diarrhea, dizziness, and vomiting. The most common adverse reaction leading to discontinuation with the 400 mg intravenous dose was rash. The most common adverse reactions leading to discontinuation with the 400 mg intravenous/oral sequential dose were diarrhea, pyrexia.

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% or more) Adverse Reactions Reported in Active-Controlled Clinical Trials with AVELOX

System Organ Class Adverse Reactions %
Blood and Lymphatic System Disorders Anemia 1
Gastrointestinal Disorders Nausea 7
Diarrhea 6
Vomiting 2
Constipation 2
Abdominal pain 2
Dyspepsia 1
General Disorders and Administration Site Conditions Pyrexia 1
Investigations Alanine aminotransferase increased 1
Metabolism and Nutritional Disorder Hypokalemia 1
Nervous System Disorders Headache 4
Dizziness 3
Psychiatric Disorders Insomnia 2

Table 3: Less Common (0.1 to less than 1%) Adverse Reactions Reported in Active-Controlled Clinical Trials with AVELOX (N=14,981)

System Organ Class Adverse Reactions
Blood and Lymphatic System Disorders Thrombocythemia
Cardiac Disorders Atrial fibrillation
System Organ Class Adverse Reactions
Angina pectoris
Cardiac failure
Cardiac arrest
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
Infusion site extravasation
Chest discomfort
Facial pain
Hepatobiliary disorders Hepatic function abnormal
Infections and Infestations Candidiasis
Vaginal infection
Fungal infection
Investigations Aspartate aminotransferase increased
Gamma-glutamyltransferase increased
Blood alkaline phosphatase increased
Electrocardiogram QT prolonged
Blood lactate dehydrogenase increased
Blood amylase increased
Lipase increased
Blood creatinine increased
Blood urea increased
Hematocrit decreased
Prothrombin time prolonged
Eosinophil count increased
Activated partial thromboplastin time prolonged
Blood triglycerides increased
Blood uric acid increased
Metabolism and Nutrition Disorders Hyperglycemia
Decreased appetite
Musculoskeletal and Connective Tissue Disorders Back pain
Pain in extremity
Muscle spasms
Musculoskeletal pain
Nervous System Disorders Dysgeusia
System Organ Class Adverse Reactions
Psychiatric Disorders Anxiety
Confusional state
Renal and Urinary Disorders Renal failure
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

Laboratory Changes

Changes in laboratory parameters, which are not listed above and which occurred in 2% or more of patients and at an incidence greater than in controls included: increases in mean corpuscular hemoglobin (MCH), neutrophils, white blood cells (WBCs), prothrombin time (PT) ratio, ionized calcium, chloride, albumin, globulin, bilirubin; decreases in hemoglobin, red blood cells (RBCs), neutrophils, eosinophils, basophils, glucose, oxygen partial pressure (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 below lists adverse reactions that have been identified during post-approval use of AVELOX. Because these reactions 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
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)
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 [seeWARNINGS AND PRECAUTIONS]
Nervous System Disorders Altered coordination
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 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

Fluoroquinolones, including AVELOX, form chelates with alkaline earth and transition metal cations. Oral administration of AVELOX 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 didanosine buffered tablets for oral suspension or the pediatric powder for oral solution, may substantially interfere with the absorption of AVELOX, 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 and CLINICAL PHARMACOLOGY]


Fluoroquinolones, 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 AVELOX is administered concomitantly with warfarin or its derivatives. [See ADVERSE REACTIONS and CLINICAL PHARMACOLOGY]

Antidiabetic Agents

Disturbances of blood glucose, including hyperglycemia and hypoglycemia, have been reported in patients treated concomitantly with fluoroquinolones, including AVELOX, and an antidiabetic agent. Therefore, careful monitoring of blood glucose is recommended when these agents are co-administered. If a hypoglycemic reaction occurs, AVELOX should be discontinued and appropriate therapy should be initiated immediately. [See WARNINGS AND PRECAUTIONS and ADVERSE REACTIONS].

Nonsteroidal Anti-Inflammatory Drugs

The concomitant administration of a nonsteroidal anti-inflammatory drug (NSAID) with a fluoroquinolone, including AVELOX, may increase the risks of CNS stimulation and convulsions [see WARNINGS AND PRECAUTIONS].

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 AVELOX in dogs. Therefore, AVELOX should be avoided with Class IA and Class III antiarrhythmics. [See WARNINGS AND PRECAUTIONS and Nonclinical Toxicology.]

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

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 9/2/2015

Side Effects

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