Follow Us


Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

More common

  • Diarrhea

Less common

  • Abdominal or stomach pain
  • Abdominal or stomach tenderness
  • Agitation
  • Anxiety
  • Black, tarry stools
  • Bleeding gums
  • Bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
  • Blood in the urine or stools
  • Bluish color
  • Blurred vision
  • Bone or skeletal pain
  • Burning feeling in the chest or stomach
  • Changes in skin color
  • Chest pain
  • Cloudy urine
  • Cold sweats
  • Coma
  • Confusion
  • Cool, pale skin
  • Cough
  • Dark urine
  • Decrease in urine output or decrease in urine-concentrating ability
  • Depression
  • Difficult or labored breathing
  • Difficulty with moving
  • Difficulty with swallowing
  • Discouragement
  • Dizziness
  • Dry mouth
  • Fainting
  • Fast, irregular, pounding, or racing heartbeat or pulse
  • Fear or nervousness
  • Feeling sad or empty
  • Fever with or without chills
  • Flushed, dry skin
  • Fruit-like breath odor
  • Headache
  • Heartburn
  • Hives or welts
  • Hostility
  • Hyperventilation
  • Increased hunger
  • Increased thirst
  • Increased urination
  • Indigestion
  • Irregular heartbeats
  • Irritability
  • Itching
  • Itching of the vagina or genital area
  • Joint pain or stiffness
  • Lack of appetite
  • Lethargy
  • Light-colored stools
  • Loss of appetite
  • Loss of interest or pleasure
  • Mood or mental changes
  • Muscle aching or cramping
  • Muscle twitching
  • Nausea and vomiting
  • Nightmares
  • No blood pressure or pulse
  • Numbness or tingling in the hands, feet, or lips
  • Pain
  • Pain during sexual intercourse
  • Pain or burning in the throat
  • Pale skin
  • Pinpoint red spots on the skin
  • Puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • Rapid weight gain
  • Rash
  • Redness of the skin
  • Redness, swelling, or soreness of the tongue
  • Restlessness
  • Seeing, hearing, or feeling things that are not there
  • Seizures
  • Severe abdominal or stomach cramps and pain
  • Shakiness in the legs, arms, hands, or feet
  • Shortness of breath
  • Skin rash
  • Slurred speech
  • Sore throat
  • Sores, ulcers, or white spots on the lips or tongue or inside the mouth
  • Stopping of the heart
  • Stupor
  • Sweating
  • Swelling of the face, ankles, or hands
  • Swelling of the foot or leg
  • Swollen joints
  • Tenderness in the stomach area
  • Thick, white vaginal discharge with no odor or with a mild odor
  • Tightness in the chest
  • Trembling or shaking of the hands or feet
  • Trouble with concentrating
  • Trouble with sleeping
  • Troubled breathing with exertion
  • Unconsciousness
  • Unexplained weight loss
  • Unusual bleeding or bruising
  • Unusual tiredness or weakness
  • Vaginal yeast infection
  • Watery and severe diarrhea, which may also be bloody
  • Weakness or heaviness of the legs
  • Wheezing
  • Yellow eyes or skin

Incidence not known

  • Back, leg, or stomach pains
  • Burning, numbness, tingling, or painful sensations
  • Continuing ringing or buzzing or other unexplained noise in the ears
  • Delusions of persecution, mistrust, suspiciousness, or combativeness
  • Difficulty with chewing or talking
  • Double vision
  • Drooping eyelids
  • Drowsiness
  • Feeling faint, dizzy, or lightheadedness
  • Feeling of warmth or heat
  • Feeling that others are watching you or controlling your behavior
  • Feeling that others can hear your thoughts
  • Feeling, seeing, or hearing things that are not there
  • Flushing or redness of the skin, especially on the face and neck
  • General body swelling
  • General feeling of discomfort or illness
  • Greatly decreased frequency of urination or amount of urine
  • Hearing loss
  • High fever
  • Irregular or slow heart rate
  • Muscle weakness
  • Nosebleeds
  • Painful or difficult urination
  • Painful, swollen joints
  • Pale skin
  • Rapid, shallow breathing
  • Red, irritated eyes
  • Red skin lesions, often with a purple center
  • Reddening of the skin, especially around the ears
  • Swelling of the eyes, face, or inside of the nose
  • Sensation of skin burning
  • Severe mood or mental changes
  • Severe tiredness
  • Skin blisters
  • Stiff neck
  • Stomach pain, continuing
  • Swollen or painful glands
  • Thickening of bronchial secretions
  • Thoughts or attempts at killing oneself
  • Unpleasant breath odor
  • Unsteadiness or awkwardness
  • Unusual behavior
  • Upper right abdominal or stomach pain
  • Vomiting of blood
  • Weakness in the arms, hands, legs, or feet

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

  • Acid or sour stomach
  • Belching
  • Change in walking and balance
  • Clumsiness or unsteadiness
  • Constipation
  • Excessive muscle tone
  • Feeling of constant movement of self or surroundings
  • Increase in body movements
  • Muscle tension or tightness
  • Sensation of spinning
  • Sleepiness or unusual drowsiness
  • Sleeplessness
  • Unable to sleep
  • Weight loss

Incidence not known

  • Area of decreased vision
  • Blurred or loss of vision
  • Change in taste
  • Disturbed color perception
  • Double vision
  • Halos around lights
  • Hoarseness
  • Loss of sense of smell
  • Loss of sense of taste
  • Night blindness
  • Overbright appearance of lights
  • Transient, mild, or pleasant aromatic odor
  • Tunnel vision
  • Voice changes

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.


If your symptoms do not improve within a few days or if they become worse, check with your doctor.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and require immediate medical attention. Call your doctor or nurse right away if you have a rash; itching; hives; hoarseness; shortness of breath; trouble with breathing; trouble with swallowing; or any swelling of your hands, face, or mouth after you receive this medicine.

Serious skin reactions can occur with this medicine. Check with your doctor right away if you have blistering, peeling, or loosening of the skin; red skin lesions; severe acne or skin rash; sores or ulcers on the skin; or fever or chills while you are using this medicine.

Levofloxacin may cause serious liver problems, including hepatitis. Check with your doctor right away if you start having nausea or vomiting, dark urine, light-colored stools, stomach pain, or yellow eyes or skin while you are using this medicine.

Levofloxacin may cause diarrhea, and in some cases it can be severe. It may occur 2 months or more after you stop using this medicine. Do not take any medicine to treat diarrhea without first checking with your doctor. Diarrhea medicines may make the diarrhea worse or make it last longer. If you have any questions about this or if mild diarrhea continues or gets worse, check with your doctor.

Stop using this medicine and tell your doctor right away if you start having numbness, tingling, or burning pain in your hands, arms, legs, or feet. These may be symptoms of a condition called peripheral neuropathy.

For patients with low potassium levels or an abnormally slow heartbeat, levofloxacin may increase your risk of having a fast, slow, or irregular heartbeat. Call your doctor right away if you feel that your heart is not beating normally.

Some people who take levofloxacin may become more sensitive to sunlight than they are normally. Exposure to sunlight, even for brief periods of time, may cause severe sunburn or skin rash, redness, itching, or discoloration. When you begin using this medicine:

  • Stay out of direct sunlight, especially between the hours of 10:00 a.m. and 3:00 p.m., if possible.
  • Wear protective clothing, including a hat and sunglasses.
  • Apply a sun block product that has a skin protection factor (SPF) of at least 15. Some people may require a product with a higher SPF number, especially if they have a fair complexion. If you have any questions about this, check with your doctor.
  • Do not use a sun lamp or tanning bed or booth.

If you have a severe reaction from the sun, check with your doctor.

Levofloxacin may cause some people to become dizzy, lightheaded, drowsy, or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert. If these reactions are especially bothersome, check with your doctor.

Levofloxacin may rarely cause inflammation or even tearing of a tendon (the cord that attaches muscles to the bones). The risk of having tendon problems may be increased if you are over 60 years of age, using steroid medicines (e.g., dexamethasone, prednisolone, prednisone, or Medrol®), have severe kidney problems, have a history of tendon problems (e.g., rheumatoid arthritis), or have received an organ (e.g., heart, kidney, or lung) transplant. If you get sudden pain or swelling in a tendon after exercise (e.g., in the ankle, back of the knee or leg, shoulder, elbow, or wrist), stop using this medicine and check with your doctor right away. Refrain from exercise until your doctor says otherwise.

For diabetic patients taking insulin or oral medicine: Levofloxacin may cause hypoglycemia (low blood sugar) in some patients. Symptoms of low blood sugar must be treated before they lead to unconsciousness (passing out). Different people may feel different symptoms of low blood sugar. If you experience symptoms of low blood sugar, stop using levofloxacin and check with your doctor right away:

  • Symptoms of low blood sugar can include: Anxious feeling, behavior change similar to being drunk, blurred vision, cold sweats, confusion, cool pale skin, difficulty with concentrating, drowsiness, excessive hunger, headache, nausea, nervousness, rapid heartbeat, shakiness, or unusual tiredness or weakness.

Before you have any medical tests, tell the medical doctor in charge that you are using this medicine. The results of some tests may be affected by this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Proper Use

A nurse or other trained health professional will give you or your child this medicine. This medicine is given through a needle placed in one of your veins. The medicine must be injected slowly, so the needle will need to stay in place for at least one hour.

Your doctor will give you or your child a few doses of this medicine until your condition improves, and then switch you or your child to an oral medicine that works the same way. If you have any concerns about this, talk to your doctor.

This medicine comes with a Medication Guide. It is very important that you read and understand this information. Be sure to ask your doctor about anything you do not understand.

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Use is not recommended for infants, children, or teenagers. However, levofloxacin injection may be used in children to treat anthrax infection after possible exposure.


Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of levofloxacin injection in the elderly. However, elderly patients are more likely to have tendon disorders (including tendon rupture) and kidney, liver, or heart problems, which may require caution and an adjustment in the dose for patients receiving levofloxacin injection.


Pregnancy Category Explanation
All Trimesters C Animal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.


There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Dronedarone
  • Mesoridazine
  • Thioridazine

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Acarbose
  • Acecainide
  • Acetohexamide
  • Amiodarone
  • Asenapine
  • Azimilide
  • Benfluorex
  • Bretylium
  • Chlorpromazine
  • Chlorpropamide
  • Citalopram
  • Crizotinib
  • Disopyramide
  • Dofetilide
  • Droperidol
  • Fluconazole
  • Gliclazide
  • Glimepiride
  • Glipizide
  • Gliquidone
  • Glyburide
  • Guar Gum
  • Haloperidol
  • Ibutilide
  • Iloperidone
  • Insulin
  • Insulin Aspart, Recombinant
  • Insulin Glulisine
  • Insulin Lispro, Recombinant
  • Lapatinib
  • Lumefantrine
  • Metformin
  • Methadone
  • Miglitol
  • Moricizine
  • Nilotinib
  • Pazopanib
  • Perphenazine
  • Procainamide
  • Prochlorperazine
  • Quetiapine
  • Quinidine
  • Ranolazine
  • Sematilide
  • Sotalol
  • Sunitinib
  • Tedisamil
  • Telavancin
  • Tetrabenazine
  • Theophylline
  • Tolazamide
  • Tolbutamide
  • Toremifene
  • Trifluoperazine
  • Troglitazone
  • Vandetanib
  • Vemurafenib
  • Warfarin
  • Ziprasidone

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Betamethasone
  • Corticotropin
  • Cortisone
  • Cosyntropin
  • Deflazacort
  • Dexamethasone
  • Fludrocortisone
  • Fluocortolone
  • Hydrocortisone
  • Methylprednisolone
  • Paramethasone
  • Prednisolone
  • Prednisone
  • Triamcinolone

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Brain or spinal cord disease, including hardening of the arteries in the brain, or epilepsy or other seizures or
  • Diabetes or
  • Diarrhea or
  • Heart rhythm problems (e.g., arrhythmia, prolonged QT interval) or
  • Hypokalemia (low potassium in the blood), uncorrected—Use with caution. May make these conditions worse.
  • Kidney disease—Use with caution. The effects may be increased because of slower removal of levofloxacin from the body.
  • Myasthenia gravis (severe muscle weakness)—Should not be used in patients with this condition.
  • Organ transplant (e.g., kidney, heart, or lung transplant) or
  • Tendon disorder (e.g., rheumatoid arthritis), history of—Use with caution. May increase the risk of tendon problems.


Levofloxacin injection is used to treat bacterial infections in many different parts of the body. It is also used to treat anthrax infection after possible exposure.

Levofloxacin belongs to the class of medicines known as fluoroquinolone antibiotics. It works by killing bacteria or preventing their growth. However, this medicine will not work for colds, flu, or other virus infections.

This medicine is available only with your doctor’s prescription.