Levofloxacin Side Effects: What Are They?

Published July 15th, 2020 by Bridget Reed
Fact Checked by
Chris Riley

Most people in the United States will need to take an antibiotic at some point in their lives, whether they have a urinary tract infection, a skin infection, or some other type of bacterial infection, like acne. While some medications have a wide variety of applications and are considered broad-spectrum antibiotics, others, like levofloxacin, are medications that are used when only a powerful drug will effectively be able to fight the infection. Levofloxacin is a fluoroquinolone antibiotic used to treat pneumonia, help people who have inhaled anthrax, and prevent infection from the plague, but it also can be used in situations where other antibiotics are not effective. There are numerous side effects and warnings associated with levofloxacin, so healthcare professionals do not prescribe the drug unless it is absolutely necessary to treat a serious infection; levofloxacin was prescribed 3,777,117 times in 2017 in the United States. Over the past several decades, many viral infections like the common cold and flu have been treated mistakenly with antibiotics, which has led to a rise in drug-resistant bacteria. In these situations, levofloxacin can be a helpful alternative, but we also need to address the issue of levofloxacin side effects: what are they?


Levofloxacin is the generic version of the brand name drug Levaquin, which was first approved by the U.S. Food and Drug Administration (FDA) in 1996. The medication was originally approved for the treatment of bacterial sinusitis, bacterial bronchitis, pneumonia, skin infections, urinary tract infections, and acute pyelonephritis (kidney disease).  Levofloxacin is an antibiotic used to treat bacterial infections, and it belongs to a class of drugs called quinolone antibiotics. Antibiotics work by stopping the growth of bacteria in the body and killing existing bacteria. Although antibiotics are often prescribed for things like upper respiratory infections, the common cold, and the flu, they are not effective at treating these viral infections.  

Conditions Treated

As noted above, levofloxacin is used to treat a variety of conditions resulting from bacterial infections. Generally speaking, levofloxacin is used to treat only infections that are inherently serious, such as pneumonia, or infections that have not been cured by other antibiotics and have continued to progress. Levofloxacin is used to treat pneumonia, sinus infection, worsening bronchitis, skin infections, chronic prostate infections, severe urinary tract infections, kidney infections, inhalation of anthrax, and plague. Common bacterial infections, such as most sexually transmitted diseases, acne, and most urinary tract infections, are not treated by levofloxacin and are instead treated with lower strength broad-spectrum antibiotics. The medication is sometimes taken with other medications in a strategy called combination therapy. 

Causes of Bacterial Infections

At any given time, our bodies are filled with trillions of bacteria and other living organisms that make up our microbiome. The bacteria are present in our gut, our mouths, our genitals, and more, and they play an important role in how our bodies function. Bacteria can be good, bad, or neutral depending on the size of their population within our bodies and their location. Probiotics, or “good” bacteria, carry out important functions in the body like helping to digest food and support our immune systems, and they also fight disease. Harmful bacteria are called pathobiotics, and these bacteria can cause infections that are treated by levofloxacin. Eubiotics are bacteria that can function as either probiotics or pathobiotics depending on the size and location of their colony. Bacterial infections occur when the number of pathobiotics outnumbers the probiotics in a given part of the body. Typically, the probiotic bacteria in our bodies are able to fight off the pathobiotic bacteria and prevent infection, but an unbalanced microbiome causes immune health to decline and allows infections to settle in. Antibiotics are commonly used to treat bacterial infections because they work by killing the pathobiotic bacteria that are causing the infection.

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Possible Side Effects

Levofloxacin is a very effective antibiotic, but it is associated with many side effects, some of which can be serious. Due to the risk of side effects, levofloxacin is only prescribed in situations where other medications are not adequate to treat the bacterial infection. Levofloxacin can cause both mild and serious side effects. Common side effects associated with levofloxacin that usually do not require medical attention include:

  • Constipation
  • Headache
  • Insomnia (trouble sleeping)
  • Nausea
  • Diarrhea
  • Dizziness

If these common side effects do not subside within a few days or weeks or become more severe, speak to your doctor. 
Levofloxacin can cause allergic reactions or adverse effects in many different parts of the body. In the event of a serious drug reaction, you should seek medical help from a medical professional. Symptoms of an allergic reaction may include:

  • Hives
  • Trouble breathing or swallowing
  • Throat tightness or hoarseness
  • Fainting
  • Swelling of the face, lips, and tongue
  • Fast heart rate
  • Skin rash or blistering

Experiencing any of the following severe side effects of levofloxacin is a sign of a medical emergency and medical advice should be sought at once:

  • Central nervous system effects, including:
    • Suicidal thoughts or actions
    • Seizures
    • Restlessness
    • Tremors
    • Confusion
    • Trouble sleeping
    • Lightheadedness
    • Hallucinations
    • Anxiety
    • Depression
    • Nightmares
    • Paranoia
    • A headache that will not go away, with or without blurred vision
  • Tendon problems and inflammation, including pain and reduced ability to move
  • Liver damage, which can sometimes be fatal. Symptoms include
    • Loss of appetite
    • Vomiting
    • Weakness
    • Itching
    • Light-colored bowel movements
    • Dark-colored urine
    • Nausea
    • Fever
    • Tiredness
    • Yellowing of the skin or whites of the eyes
    • Bruising
    • Stomach pain
  • Severe diarrhea caused by Clostridium difficile
    • Watery and bloody stools
    • Fever
    • Stomach cramps
  • Peripheral neuropathy, including pain, numbness, or weakness in the hands, feet, arms, or legs
  • Joint and muscle pain
  • Heart rhythm problems, including prolongation of the QT interval
    • Loss of consciousness
    • Irregular heartbeat
  • Increased sensitivity to the sun and severe sunburn


Prior to the release of the generic levofloxacin, Levaquin was an extremely expensive antibiotic. The release of generic levofloxacin has provided an affordable alternative to Levaquin, which has lowered in price but remains out of reach for many Americans. Levofloxacin is available in the form of tablets and an ophthalmic solution used for eye infections. Healthcare professionals also have the option of administering an injection of the medication, but the injectable form of the drug is not available to consumers. Levofloxacin is available in 250 mg, 500 mg, and 750 mg strengths. An average prescription of levofloxacin will cost approximately ten dollars to fill regardless of the strength or even the number of pills prescribed. Levaquin is available at only 500 mg and 750 strengths and costs between 300 - 600 dollars for ten tablets, depending on the strength of the medication. The costs of brand name medications are often substantially higher than those of the generic form of the medication, so many people opt to choose the generic version of their medication unless a medical issue or health condition prevents them from doing so. Generic medications offer the same quality, safety, and effectiveness of brand name medications at a greatly reduced cost.  Levofloxacin is covered by most insurance plans, including Medicare and Medicaid, as well as most commercial insurance programs. However, insurance may not always offer the best prices on prescription drugs. Pharmacy discount card programs like USA Rx also offer savings on all FDA-approved brand name and generic medications, including omeprazole, and patients can sign up for free. 


The dose of levofloxacin you will take will be decided by your prescribing physician based on the condition being treated, the severity of the infection, your age, and medical history. Levofloxacin is available in 250 mg, 500 mg, and 750 mg tablets and is also available as an ophthalmic solution and an injection given only by healthcare providers. Most infections are treated with either a 500 mg or 750 mg dose of levofloxacin taken once per day. However, infections that are typically treated with other antibiotics, such as urinary tract infections that have not responded to a different medication, may be treated by the 250 mg dose. Levofloxacin must be taken exactly as directed by your doctor for the entire course of treatment. Patients should not skip doses or stop taking the medication before the prescribed period of treatment is over, even if their symptoms have improved. Skipping doses or extending the length of your prescription can increase your risk of a future infection by unnecessarily exposing your body to antibiotics, allowing them to become drug-resistant. Follow your doctor’s orders exactly, read the drug information thoroughly, and store it at room temperature.
When taking your daily dose of levofloxacin, be sure to take it with a full glass of water. Some people may experience an upset stomach when taking levofloxacin; if this occurs, talk to your doctor about whether you can take the medication with food. Levofloxacin is only prescribed to children for the treatment of the plague or inhalation of anthrax and is not prescribed for other conditions due to the risks and side effects associated with the medication. Senior citizens and people with kidney damage or disease are at an increased risk of side effects and may need to take a lower dosage of the drug to treat their infection, as these groups often have reduced kidney function that causes the drug to build up in their systems in higher quantities.


One of the most significant benefits of levofloxacin is that the medication can effectively treat a number of serious bacterial infections that cannot be treated by alternative medications.  It is capable of treating kidney, bladder, prostate, skin, and sinus infections caused by bacteria, and it is used as a second treatment for urinary tract infections, chronic bronchitis, and sinusitis when other treatments are not effective. Additionally, levofloxacin is capable of treating many different species of bacteria, including species that are resistant to other antibiotics. Both a generic and brand name form of the drug are available, so you are likely to have one of the forms of the medication covered by your insurance company. If you do not have health insurance, levofloxacin and Levaquin are eligible for discounts under any pharmacy discount card program, including USA Rx. 

Risks and Warnings

Unfortunately, although there are many benefits associated with levofloxacin, there are also some serious risks that go along with the use of the medication. Levofloxacin has numerous black box warnings from the FDA, which are the most serious warnings that the agency offers. It is for this reason that levofloxacin is used only to treat serious infections or infections that have not responded to other types of treatment. Black box warnings associated with levofloxacin include:

  • Tendon rupture and tendonitis: Levofloxacin is associated with an increased risk of tendon rupture and inflammation of the tendons regardless of the age of the patient. However, risks are higher for patients over the age of 60, those taking corticosteroids or people who have had heart, kidney, or lung transplants.
  • Myasthenia gravis: Levofloxacin can cause a worsening of muscle weakness in patients with myasthenia gravis. These patients should not take levofloxacin.
  • Peripheral neuropathy: Levofloxacin can cause damage to the nerves in your hands, arms, feet, and legs, called peripheral neuropathy, that can be permanent.
  • Restricted use: Due to the potential for serious side effects, some of which may be permanent, levofloxacin should only be taken for certain conditions when no other treatment options exist. 
  • Central nervous system: Levofloxacin can impact your central nervous system and cause convulsions, increased pressure in the head, psychosis, hallucinations, tremors, agitation, anxiety, confusion, and other mental issues. It can also increase suicidal thoughts or actions. 


People who are allergic to levofloxacin or other quinolone antibiotics should not take levofloxacin. People who have a history of any of the following conditions should make sure to give their doctor a complete medical history:

  • Myasthenia gravis
  • Diabetes
  • Kidney damage
  • Liver problems
  • History of depression or mental illness
  • Heart conditions and chest pain

Use in Pregnant and Nursing Women

Levofloxacin is categorized as a Category C drug for pregnant women by the FDA, meaning that not enough human studies have been conducted to know how the drug might impact a developing fetus. Research in animals has shown that the drug may cause adverse effects. It is recommended that patients and their doctors weigh the benefits and risks of using the medication before choosing levofloxacin, as a serious infection could also have detrimental impacts on the developing fetus. Levofloxacin does pass into breast milk and cause harmful side effects to a nursing infant, so nursing mothers should talk to their doctors and decide whether to continue taking the drug or whether to stop breastfeeding. 

Published July 15th, 2020 by Bridget Reed
Fact Checked by
Chris Riley

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