Levofloxacin belongs to the class of medications called quinolones. It is an antibiotic used for the treatment of certain bacterial infections. It is most commonly used to treat infections of the bladder, kidney, prostate, sinus, skin, and lung.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The usual recommended adult dose of levofloxacin ranges from 250 mg to 750 mg daily. The exact dose and length of treatment depends on the condition being treated and other medical conditions present.

This medication may be taken with or without food. Levofloxacin should be taken at least 2 hours before or 2 hours after taking antacids containing calcium, magnesium, or aluminum; sucralfate; or vitamin and mineral tablets containing calcium, iron, or zinc. Make sure to drink plenty of fluids each day while taking levofloxacin.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones given here, do not change the way that you are taking the medication without consulting your doctor.

Finish all this medication, even if you have started to feel better. Stopping before the medication is finished may cause the infection to return and be harder to treat.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not take this medication if you:

• are allergic to levofloxacin or any ingredients of the medication
• are allergic to other quinolone antibiotics
• have a history of tendinitis or tendon rupture that happened while taking any of the quinolone antibiotics

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal or stomach pain or discomfort (mild)
• constipation
• difficulty sleeping
• dizziness
• drowsiness
• headache
• heartburn
• increased sensitivity of the skin to sunlight
• itching
• lightheadedness
• mild diarrhea
• nausea
• nervousness
• skin rash
• thrush (white patches in the mouth)
• vaginal itching and discharge
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• abdominal or stomach cramps or pain (severe)
• blisters
• breathing problems
• burning, tingling sensation
• confusion or changes in thought patterns (e.g., agitation, feeling that others can hear your thoughts, unusual behaviour, nervousness)
• fever
• hallucinations (seeing or hearing things that aren't there)
• increasing muscle weakness
• irregular, fast, or pounding heartbeat
• joint pain
• muscle pain
• pain, swelling, or rupture of a tendon
• pain, swelling, or warmth in the shoulders, hands, or calves
• restlessness
• signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• swelling of the hands, feet, or ankles (if you are not having difficulty breathing)
• symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
• symptoms of low blood sugar (e.g., cold sweat, cool pale skin, headache, fast heartbeat, weakness)
• trembling
• vision changes

Stop taking the medication and seek immediate medical attention if any of the following occur:

• artery dissection (sudden severe pain in the chest, back, or abdomen)
• bulge in the wall of any artery (e.g., chest, arm, leg, brain, heart – cough, coughing blood, unusual pain high in neck or back, problems swallowing, pulsing sensation in chest or abdomen)
• chest pain
• diarrhea (watery and severe; may also be bloody)
• seizures
• severe or persistent headache
• signs of an allergic reaction (e.g., difficulty breathing; hives; swelling of the face, tongue, or throat; skin rash, especially if skin is blistering, loosening, or peeling)
• thoughts of self-harm

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Abnormal heart rhythms: This medication can cause abnormal heart rhythms. Certain medications (e.g., sotalol, chlorpromazine, pimozide, moxifloxacin, mefloquine, pentamidine, arsenic trioxide, tacrolimus) can increase the risk of a type of abnormal heart rhythm called QT prolongation, and should not be used in combination with levofloxacin. You are more at risk for this type of abnormal heart rhythm and its complications if you:

• are female
• are older than 65 years of age
• have a family history of sudden cardiac death
• have a history of heart disease or abnormal heart rhythms
• have a slow heart rate
• have congenital prolongation of the QT interval
• have diabetes
• have had a stroke
• have low potassium, magnesium, or calcium levels
• have nutritional deficiencies

If you have heart disease and abnormal heart rhythms, or are taking certain medications (e.g., verapamil, atazanavir), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Allergic reactions: In rare cases, some people may develop an allergic reaction to this medication. Signs of an allergic reaction include a severe rash, swollen face, or difficulty breathing. If these occur, contact your doctor immediately.

Blood sugar levels: Levofloxacin may cause a loss of control of blood sugar levels and glucose tolerance may change. People with diabetes may find it necessary to monitor their blood sugar more frequently while using this medication. People without diabetes have also been known to experience high or low blood sugars while taking levofloxacin.

If you have diabetes or are at risk for developing diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you experience signs of high blood sugar (fruity breath odour, weight loss, increased thirst, or increased need to urinate) or low blood sugar (cold sweat, cool pale skin, headache, or weakness) contact your doctor.

Drowsiness/reduced alertness: Levofloxacin may cause dizziness or lightheadedness, which can affect the mental abilities needed to drive or operate machinery. Avoid driving or performing other potentially hazardous tasks until you have determined how this medication affects you.

Kidney function: The safety of levofloxacin for people with decreased kidney function has not been studied. Because levofloxacin is removed by the body mostly by the kidneys, it is possible that kidney disease or reduced kidney function may cause this medication to build up in the body, causing side effects. If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Very rarely, levofloxacin may reduce liver function and can cause liver failure. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.

Myasthenia gravis: Myasthenia gravis is an autoimmune disorder that causes specific muscle weakness. Levofloxacin may make muscle weakness worse. If you have myasthenia gravis, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Nervous system disorders: Rare cases of disorders that affect the nervous system have been reported by people taking this medication. If you are experiencing seizures, tremors, confusion, hallucinations, depression, agitation, anxiety, paranoia, or disturbing thoughts, contact your doctor immediately.

Peripheral neuropathy: Although rare, levofloxacin may affect the nerves of the skin and limbs. If you start to feel pain, burning, tingling, numbness, or weakness, stop taking this medication and contact your doctor immediately.

Seizures: There have been occasional reports of seizures occurring with quinolone antibiotics. Seizures are more likely to occur when higher doses of this medication are taken. If you have a history of epilepsy or medical conditions that increase the risk of seizures, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Stomach problems (especially colitis): In rare cases, levofloxacin may cause a condition called pseudomembranous colitis (serious antibiotic-induced diarrhea). Therefore, if diarrhea occurs after starting the medication, contact your doctor.

Sun sensitivity: People who take levofloxacin are more likely to experience sunburn. While taking levofloxacin, be careful if you spend time in the sun. Avoid exposure to excessive sunlight, including sunlamps and tanning beds, and use sunblock with minimum SPF 15. Stop taking levofloxacin if severe sun sensitivity occurs.

Tendinitis: Levofloxacin, like other antibiotics in this group, may increase the chance of tendon injury. In some cases, this effect may be long-lasting. Injuries occur more commonly for seniors, people taking corticosteroid medications, and people who have had a kidney, heart, or lung transplant. If you feel any new pain in the tendons, stop taking levofloxacin, avoid physical exercise, and consult your doctor.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication may pass into breast milk. If you are a breast-feeding mother and are taking levofloxacin, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children and adolescents: The safety and effectiveness of levofloxacin for children and adolescents younger than 18 years of age have not been established. Children who have not reached puberty should not take levofloxacin, since it may affect the normal growth of bones.

Seniors: People over the age of 65 are more likely to experience serious side effects of levofloxacin, such as tendinitis, liver toxicity, or heart problems.

There may be an interaction between levofloxacin and any of the following:

• amphetamines (e.g., dextroamphetamine, lisdexamfetamine)
• antacids containing aluminum hydroxide and magnesium hydroxide (do not take within 2 hours of levofloxacin)
• antiarrhythmics (e.g., amiodarone, dronedarone, flecainide)
• antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
• "azole" antifungals (e.g., fluconazole, voriconazole)
• BCG
• bromocriptine
• calcium supplements and multivitamins containing calcium (do not take within 2 hours of levofloxacin)
• capecitabine
• chloral hydrate
• cholera vaccine
• oral corticosteroids (e.g., dexamethasone, hydrocortisone, prednisone)
• diabetes medications (e.g., acarbose, canagliflozin, chlorpropamide, glyburide, insulin, metformin, rosiglitazone)
• domperidone
• hydroxychloroquine
• iron supplements and multivitamins containing iron (do not take within 2 hours of levofloxacin)
• macrolide antibiotics (e.g., azithromycin, clarithromycin, erythromycin)
• magnesium supplements (e.g., magnesium hydroxide, magnesium oxide, magnesium sulfate)
• methadone
• methotrexate
• methylphenidate
• mifepristone
• moxifloxacin
• multivitamins
• multivitamins with minerals
• mycophenolate
• nonsteroidal anti-inflammatory medications (e.g., diclofenac, ibuprofen, ketoprofen, naproxen)
• pentamidine
• quinine
• ondansetron
• saquinavir
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, escitalopram)
• sevelamer
• sodium picosulfate
• somatostatin-like medications (e.g., lanreotide, octreotide, pasireotide)
• sotalol
• sucralfate (do not take within 2 hours of levofloxacin)
• sulfamethoxazole
• tacrolimus
• theophyllines (e.g., aminophylline, oxtriphylline, theophylline)
• thioridazine
• tramadol
• tricyclic antidepressants (e.g., clomipramine, doxepin, imipramine)
• typhoid vaccine
• tyrosine kinase inhibitors (e.g., dasatinib, nilotinib, sunitinib)
• warfarin
• zinc supplements

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.