Last updated on RxList: 3/25/2020
Avelox Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

What Is Avelox?

Avelox (moxifloxacin) is a fluoroquinolone antibiotic that inhibits certain bacteria that may cause infections such as pneumonia, bronchitis, and others that may infect the sinuses, skin or abdomen. Avelox is available as generic moxifloxacin.

What Are Side Effects of Avelox?

Common side effects of Avelox include:

  • abdominal discomfort
  • diarrhea
  • nausea
  • vomiting
  • mouth sores
  • headache
  • dizziness
  • blurred vision
  • nervousness
  • anxiety
  • agitation
  • skin itching, and
  • vaginal discomfort (itch or burning sensation)

Dosage for Avelox

Avelox is available in tablets of 400 mg strength, and is usually given as a 400 mg strength dose once per day. Length of therapy depends on the type of infection. Serious side effects of Avelox include severe diarrhea, acute allergic reactions, renal problems, and connective tissue problems (tendon rupture and joint problems), muscle pain, confusion, agitation, depression, and skin problems.

What Drugs, Substances, or Supplements Interact with Avelox?

In addition, the drug may prolong the QT heartbeat interval cause warfarin (Coumadin) levels to be higher than normal and make symptoms of myasthenia gravis worse.

Avelox During Pregnancy and Breastfeeding

Avelox should be used during pregnancy and lactating women only if the potential benefit justifies the potential risk to the fetus or infant. As stated above, Avelox should not be used in pediatric patients. Although Avelox may be effective against a wide range of bacteria, good clinical practice suggests the sensitivities of infective organisms to Avelox be determined.

Additional Information

Our Avelox Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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Avelox Consumer Information

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning in your eyes, skin pain, red or purple skin rash that spreads and causes blistering and peeling).

Moxifloxacin can cause serious side effects, including tendon problems, side effects on your nerves (which may cause permanent nerve damage), serious mood or behavior changes (after just one dose), or low blood sugar (which can lead to coma).

Stop using this medicine and call your doctor at once if you have:

  • low blood sugar--headache, hunger, sweating, irritability, dizziness, nausea, fast heart rate, or feeling anxious or shaky;
  • nerve symptoms in your hands, arms, legs, or feet--numbness, weakness, tingling, burning pain;
  • serious mood or behavior changes--nervousness, confusion, agitation, paranoia, hallucinations, memory problems, trouble concentrating, thoughts of suicide; or
  • signs of tendon rupture--sudden pain, swelling, bruising, tenderness, stiffness, movement problems, or a snapping or popping sound in any of your joints (rest the joint until you receive medical care or instructions).

In rare cases, moxifloxacin may cause damage to your aorta, the main blood artery of the body. This could lead to dangerous bleeding or death. Get emergency medical help if you have severe and constant pain in your chest, stomach, or back.

Also stop using moxifloxacin and call your doctor at once if you have:

  • severe stomach pain, diarrhea that is watery or bloody;
  • fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out);
  • muscle weakness, breathing problems;
  • a seizure (convulsions);
  • any skin rash, no matter how mild;
  • increased pressure inside the skull--severe headaches, ringing in your ears, vision problems, pain behind your eyes; or
  • liver problems--upper stomach pain, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Common side effects may include:

  • nausea, diarrhea;
  • dizziness; or
  • headache.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Avelox (Moxifloxacin HCL)


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Avelox Professional Information


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 % (N=14,981)
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 Eosinophilia Neutropenia Thrombocytopenia Leukopenia Leukocytosis
Cardiac Disorders Atrial fibrillation Palpitations Tachycardia Angina pectoris Cardiac failure Cardiac arrest Bradycardia
Ear and Labyrinth Disorders Vertigo Tinnitus
Eye Disorders Vision blurred
Gastrointestinal Disorders Dry mouth Abdominal discomfort Flatulence Abdominal distention Gastritis
Gastroesophageal reflux disease
General Disorders and Administration Site Conditions Fatigue Chest pain Asthenia Pain Malaise Infusion site extravasation Edema Chills Chest discomfort Facial pain
Hepatobiliary disorders Hepatic function abnormal
Infections and Infestations Candidiasis Vaginal infection Fungal infection Gastroenteritis
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 Anorexia Hyperlipidemia Decreased appetite Dehydration
Musculoskeletal and Connective Tissue Disorders Back pain Pain in extremity Arthralgia Muscle spasms
Musculoskeletal pain
Nervous System Disorders Dysgeusia Somnolence Tremor Lethargy Paresthesia Hypoesthesia Syncope
Psychiatric Disorders Anxiety Confusional state Agitation Depression Nervousness Restlessness Hallucination Disorientation
Renal and Urinary Disorders Renal failure Dysuria
Reproductive System and Breast Disorders Vulvovaginal pruritus
Respiratory, Thoracic, and Mediastinal Disorders Dyspnea Asthma Wheezing Bronchospasm
Skin and Subcutaneous Tissue Rash
Disorders Pruritus Hyperhidrosis Erythema Urticaria Dermatitis allergic Night sweats
Vascular Disorders Hypertension Hypotension Phlebitis

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 Reactions
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 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 entire FDA prescribing information for Avelox (Moxifloxacin HCL)

© Avelox Patient Information is supplied by Cerner Multum, Inc. and Avelox Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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