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Boxed warning

Levofloxacin and other fluoroquinolone antibiotics have a black box label warning. It warns against the following serious adverse effects that can be disabling or potentially irreversible:¹

  • Tendinitis and tendon rupture. This risk is greater in people over the age of 60, taking corticosteroids, and with lung, heart, or kidney transplants.

  • Worsening muscle weakness in people with myasthenia gravis, a neuromuscular condition that causes muscle weakness and muscle fatigue.

  • Peripheral neuropathy, a condition characterized by nerve damage that causes pain, numbness, and muscle problems.

  • Central nervous system effects, including psychiatric effects (like nervousness, memory difficulties, disorientation, and agitation), seizures, tremors, lightheadedness, and others.

Speak to your doctor about the drug’s potential side effects before starting treatment and seek medical help if you develop any of the serious side effects listed in the “Potential side effects of levofloxacin” section of this article.

In addition to the above warning, the black box information includes several indications for using levofloxacin when no other drug is available. See the “What does levofloxacin treat?” section.

List of conditions levofloxacin treats

  • Bacterial pneumonia

  • Skin infections

  • Chronic prostatitis

  • Pyelonephritis (kidney infection)

  • Anthrax (for prevention after exposure)

  • Plague

  • Bacterial eye infections

  • Chronic bacterial bronchitis

  • Acute bacterial sinusitis

  • Uncomplicated urinary tract infection (UTI)

What is levofloxacin?

Levofloxacin is a type of fluoroquinolone antibiotic used to treat several types of bacterial infections.²

Bacteria contain DNA as part of their genetic makeup. It divides and replicates for the microorganisms to multiply and grow. Fluoroquinolone antibiotics work to inhibit certain proteins that are necessary for DNA production in bacteria.

What does levofloxacin treat?

The drug is FDA approved to treat:³

  • Bacterial pneumonia

  • Skin infections

  • Chronic prostatitis

  • Pyelonephritis (kidney infection)

  • Anthrax (for prevention after exposure)

  • Plague

  • Bacterial eye infections

Due to the risks of the serious adverse effects mentioned in the black box warning, you should only take levofloxacin for the following conditions when no other suitable drug is available:

  • Chronic bacterial bronchitis

  • Acute bacterial sinusitis

  • Uncomplicated urinary tract infection (UTI)

Dosage forms and strengths

Generic levofloxacin for oral use is available as a tablet (250mg, 500mg, and 750mg) or liquid solution (25mg/mL).⁴

It is also provided in injectable form for IV use in severe infections and as a 0.5% ophthalmic solution for use in the eye (sold as a generic medication and as a brand-name product, Quixin).

How do you take levofloxacin?

Your exact dosage and the length of treatment will depend on the nature and severity of your infection.

Take the oral tablet with a full glass of water. You can take it with or without food.

Take the oral solution one hour before food or two hours after eating.

It’s important to drink plenty of water throughout the day to prevent dehydration while taking levofloxacin. Crystals may form in the urine if you become dehydrated.¹

Seeing results

While peak drug levels are achieved within 1–2 hours of taking levofloxacin, it can take up to three days for the medication to ease your symptoms.⁵

Finish your complete course of antibiotics even if you feel better.

Who should not take levofloxacin

Levofloxacin is not suitable for everyone. You may not be able to take levofloxacin if any of the points below apply to you:

  • You are allergic to levofloxacin or have had an allergic reaction to it in the past

  • You have a health condition that’s contraindicated with levofloxacin, including myasthenia gravis and certain heart rhythm problems like long QT syndrome

  • You have kidney disease. Levofloxacin is excreted via the kidneys, so kidney failure could cause the drug to build up in your body. Your doctor may recommend taking a lower dose.

  • You are taking a medication that interacts with levofloxacin to cause harmful effects (see the “Interactions with other drugs” section below)

  • You are pregnant or breastfeeding. Your doctor may prescribe levofloxacin only if its benefits outweigh the potential risks.

The best way to know if levofloxacin is suitable for you is to talk to your doctor.

Potential side effects of levofloxacin

Tell your doctor if you develop any of the following side effects and they persist or worsen:²

  • Diarrhea

  • Constipation

  • Nausea

  • Vomiting

  • Stomach pain

  • Heartburn

  • Vaginal discharge and/or itching

  • Insomnia

Serious side effects

Levofloxacin can cause more serious adverse effects, including the following along with their symptoms:¹ ²

  • Tendonitis:

    • Trouble moving the associated muscle(s)

    • Pain with movement

    • Stiffness

    • Tenderness

    • Swelling

  • Tendon rupture:

    • Bruising after an injury

    • Not being able to bear weight on or move the affected area

    • Feeling or hearing a pop or snap

  • Peripheral neuropathy:

    • Difficulty feeling heat, cold, pain, vibration, or light touch

    • Pain or weakness in your arms or legs

    • A numb or tingling sensation in your arms or legs

  • Psychiatric effects:

    • Difficulty remembering things

    • Feeling agitated, restless, nervous, or anxious

    • Difficulty sleeping or having nightmares

    • Trouble concentrating or becoming confused, disoriented, or delirious

    • Feeling depressed, having suicidal thoughts or actions

    • Paranoia, hallucinations, or psychosis

  • Other central nervous system effects:

    • Seizures

    • Lightheadedness

    • Tremors

    • Dizziness

  • Worsening of myasthenia gravis:

  • Allergic reaction:

    • Itching

    • Hives

    • Swelling of the face, tongue, or throat

    • Difficulty breathing

    • Low blood pressure

    • Loss of consciousness

  • Liver toxicity:

    • Yellowing of the eyes or skin

    • Dark urine

    • Stool that is light in color

  • A bulge in the aorta (the large blood vessel that carries blood from your heart):

    • Continuous lower back or stomach pain

    • A pulsing sensation in the stomach

  • A tear in the aorta:

    • Sudden pain in your back, stomach, or chest

    • Shortness of breath

    • Fast heartbeat

    • Dizziness

    • Pale, sweaty, or clammy skin

    • Loss of consciousness

  • Clostridioides difficile-associated diarrhea (CDAD) — this can occur months after levofloxacin treatment:

  • Prolonged QT interval:

    • Fainting

    • Seizures

    • Heart palpitations

  • Severely low blood sugar levels (hypoglycemia) that could lead to coma:

    • Feeling extremely hungry or thirsty

    • Fast or fluttering heartbeat

    • Needing to urinate more

    • Feeling shaky

    • Trembling

    • Sweating

    • Blurry vision

    • Feeling unusually anxious

  • Increased sensitivity to sunlight:

    • Sunburn

Speak to your doctor immediately or call 911 if you develop any signs of these serious adverse effects.


Levofloxacin overdose can occur if you take more than the prescribed dose or take it with other drugs that have similar effects.

Animal studies have shown that a single high dose of the drug can cause shortness of breath, tremors, poor muscle control, decreased mobility, convulsions, and death.¹

If you think you or someone else has taken too much levofloxacin, seek emergency medical help.

Allergy information

Levofloxacin can cause a severe allergic reaction, with symptoms including:¹

  • Itchy skin

  • Hives

  • Swollen face, tongue, or throat

  • Trouble breathing

  • Low blood pressure

  • Loss of consciousness

If you or someone else develops these symptoms, seek emergency medical assistance and stop taking levofloxacin.

Long-term use of levofloxacin

Your doctor will only recommend taking levofloxacin for a long period if the potential benefits outweigh the risks. The FDA recommends using levofloxacin for a maximum of 28 days to treat adults and 14 days to treat children.¹

Pregnancy category

Levofloxacin tablets have no assigned FDA pregnancy category.

The oral solution, injectable form for IV use, and ophthalmic solution are pregnancy category C medications.⁷ ⁸

This designation means risk cannot be ruled out. Animal studies have demonstrated that the drug can cause fetal harm, but studies in pregnant women are limited.⁹

The potential benefits of taking levofloxacin may outweigh the risks during pregnancy.

Levofloxacin and pregnancy

Reports about the use of levofloxacin during pregnancy have not shown adverse effects. However, more research is needed because the risks for fetal adverse outcomes are unknown.

The use of levofloxacin in animal studies has been shown to cause adverse effects but at doses much higher than approved human doses.¹

If you are planning a pregnancy or are currently pregnant, it is important to have a discussion with your doctor about the risks and benefits of taking levofloxacin in your situation.³

Levofloxacin and breastfeeding

Levofloxacin does pass into breast milk but in a low concentration.

While data is limited on levofloxacin’s safety for nursing mothers and newborns, it is not thought to cause harm to a nursing baby.

Your doctor may prescribe levofloxacin if they feel the benefits outweigh any potential risks and the baby can be closely monitored for adverse effects.

If your doctor tells you not to breastfeed while taking levofloxacin, they may recommend waiting two days to breastfeed after taking your last dose of medication.¹

Missed doses

Take the missed dose as soon as you remember. If it is close to the time of your next dose, skip the missed one and continue with your regular dosing schedule.

It is not safe to double up on your next scheduled dose if you have missed a dose.

Drug interactions

Levofloxacin interacts with some other drugs and can cause adverse effects.

Levofloxacin is known to interact with the following drugs (note this is not a complete list of drug interactions):¹ ³

  • Antacids that contain aluminum, magnesium, or sucralfate. Take levofloxacin two hours before or after these drugs. These interactions can reduce the absorption of levofloxacin.

  • Iron or zinc supplements. Take levofloxacin two hours before or after these supplements. Interactions with these supplements can reduce the absorption of levofloxacin.

  • Warfarin (Coumadin or Jantoven). This drug can interact with levofloxacin to increase the risk of bleeding.

  • Thioridazine. Taking levofloxacin with thioridazine (a drug for schizophrenia) could cause abnormal heart rhythms, including a prolonged QT interval.

  • Diabetes medicines. Taking levofloxacin with diabetes medications like glimepiride (Amaryl) can increase your risk of high or very low blood sugar levels.

  • Non-steroidal anti-inflammatory drugs (NSAIDs). NSAIDs like diclofenac (Cambia, Zipsor, or Zorvolex), ibuprofen (Advil, Midol, Motrin, and others), and naproxen (Aleve, Naprosyn, Anaprox, and others) can interact with levofloxacin to increase the risk of seizures.

  • Corticosteroids. Prednisone and other steroid medications can cause an increased risk of tendon rupture.

During levofloxacin treatment, do not take these or other drugs and supplements without first consulting your doctor. They may advise you to take a different drug or monitor you closely for adverse effects.

Can I drink alcohol while taking levofloxacin?

Consume alcohol with caution while taking levofloxacin. Research into how alcohol affects levofloxacin is limited.¹⁰

What to discuss with your doctor before starting levofloxacin

The following are some things to talk about with your doctor before starting levofloxacin:

  • Your medical history and current medical conditions, particularly if you have diabetes, low blood sugar, Marfan or Ehler-Danlos syndrome, myasthenia gravis, conditions that affect the blood vessels and circulation, high blood pressure, or heart, liver, kidney, or lung disease

  • If you have ever had tendon, joint, or bone problems

  • Whether you are allergic to levofloxacin or other medications or have had an allergic reaction to a medication in the past

  • All over-the-counter and prescription medications you are currently taking or plan to start taking during levofloxacin treatment, including herbal remedies and supplements

  • Whether you are pregnant, planning a pregnancy, or breastfeeding

Stopping levofloxacin

Stopping your levofloxacin treatment early without consulting your doctor could cause your infection to return or the bacteria to become resistant to the drug.

Be sure to follow your doctor’s instructions about how long to take levofloxacin and when to stop taking it.

Drug approval history

1996: The FDA first approved levofloxacin to be sold under the brand name Levaquin.

2004: An oral solution formulation of levofloxacin was approved to be sold under the brand name Levaquin.¹¹

2008: The FDA added a black box label for fluoroquinolone antibiotics, including levofloxacin. The black box label warned the public of the increased risk of tendinitis and tendon rupture.¹²

2011: The FDA issued an updated warning connecting levofloxacin use to worsening muscle weakness in people with myasthenia gravis. This information was added to the black box label.

2013: A warning about the risk of peripheral neuropathy was added to levofloxacin’s black box label, along with the fact that this adverse effect may be irreversible.

2016: Due to the risk of serious side effects, the FDA updated its warnings for levofloxacin and other fluoroquinolones to recommend they are only prescribed for chronic bacterial bronchitis, acute bacterial sinusitis, and uncomplicated UTI when no alternative treatment is available.

2017: Levaquin was discontinued in the US, but generic levofloxacin continues to be available.¹³

2018: The FDA updated warnings for levofloxacin and other fluoroquinolones. It emphasized the risk of mental health side effects, including nervousness, memory difficulties, disorientation, and agitation. It is now required that these mental health side effects are listed separately from other central nervous system side effects. In 2018, the FDA also warned of serious blood sugar disturbances.¹⁴

Tips and advice for taking levofloxacin

The following tips and advice could help you take levofloxacin safely and get the best results:

  • Take levofloxacin according to your doctor’s or pharmacist’s instructions. Do not take more or less than what you are prescribed. Try to take it at the same times every day, and avoid skipping doses.

  • Do not stop taking levofloxacin before you have completed your prescription or until your doctor tells you to.

  • Drink lots of water while you are taking levofloxacin to prevent bladder stones.

  • Wear sunscreen and avoid spending too much time in the sun while taking levofloxacin.

  • This drug can cause dizziness and difficulty concentrating. Avoid doing anything that requires high attention levels (like operating heavy machinery or driving) until you know how levofloxacin affects you.

  • Store levofloxacin tablets at 20–25ºC (68–77ºF), and keep them in an air-tight container.

  • Keep this medication out of reach of children.

Levofloxacin frequently asked questions

What is levofloxacin used for?

Levofloxacin is prescribed to treat several types of bacterial infections. It is approved to treat bacterial pneumonia, kidney infection, and chronic prostatitis among others.

What are the most serious side effects of levofloxacin?

Levofloxacin can cause serious adverse effects, including tendinitis and tendon rupture, worsening muscle weakness in people with myasthenia gravis, peripheral neuropathy, and central nervous system effects.

For how many days should levofloxacin be taken?

Your exact dosage and the length of treatment will depend on what you’re taking levofloxacin for and the severity of your infection. You must keep taking levofloxacin until you have completed your full course of treatment, even if you feel better, or until your doctor tells you to stop taking the medication.

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Here at HealthMatch, we’ve done our best to ensure that the information provided in this article is helpful, up to date, and, most importantly, accurate.

However, we can’t replace the one-to-one advice of a qualified medical practitioner or outline all of the possible risks associated with this particular drug and your circumstances.

It is therefore important for you to note that the information contained in this article does not constitute professional medical or healthcare advice, diagnosis or recommendation of treatment and is not intended to, nor should be used to, replace professional medical advice. This article may not always be up to date and is not exhaustive of all of the risks and considerations relevant to this particular drug. In no circumstances should this article be relied upon without independent consideration and confirmation by a qualified medical practitioner.

Your doctor will be able to explain all possible uses, dosages, precautions, interactions with other drugs, and other potential adverse effects, and you should always talk to them about any kind of medication you are taking, thinking about taking or wanting to stop taking.

Curious about clinical trials?

Access the latest treatments and medications. unavailable elsewhere - entirely free of charge. We make it easy to take part.