Levofloxacin

Common Uses

Levofloxacin is prescribed to treat several types of bacterial infections. It is effective against specific strains of bacteria that affect different parts of the body, including:

• Respiratory infections: This includes community-acquired pneumonia, hospital-acquired pneumonia, and acute worsening of chronic bronchitis.
• Sinus infections: It may be used for acute bacterial sinusitis.
• Urinary tract infections (UTIs): It treats complicated and uncomplicated UTIs, as well as kidney infections (pyelonephritis).
• Skin infections: It is used for both simple and complex skin and skin structure infections.
• Prostate infections: It is used to treat chronic bacterial prostatitis.

Specialized Uses

In certain situations, levofloxacin is used to treat or prevent serious conditions such as:

• Anthrax: It is used for people who may have breathed in anthrax germs (inhalational anthrax).
• Plague: It is used to treat and prevent the plague, a rare but serious bacterial infection.

Usage Restrictions

Because of the risk of serious side effects associated with fluoroquinolone antibiotics, the FDA advises that levofloxacin should only be used for certain conditions—such as uncomplicated UTIs, acute bronchitis, and acute sinusitis—when no other treatment options are available. For these conditions, the risks of the medication may outweigh the benefits if the infection is not severe.

Mechanism of Action

Levofloxacin belongs to a group of medicines known as fluoroquinolone antibiotics. It works by interfering with the way bacteria manage their DNA, which is necessary for them to grow and multiply.

Inside bacterial cells, levofloxacin targets specific enzymes called DNA gyrase and topoisomerase IV. These enzymes are responsible for uncoiling and repairing DNA so the bacteria can function. By blocking these enzymes, levofloxacin causes the following effects:

• Stops reproduction: The bacteria can no longer copy their DNA to create new cells.
• Causes DNA damage: The genetic material within the bacteria becomes unstable and breaks down.
• Eliminates the infection: Because the bacteria cannot repair themselves or multiply, they eventually die, allowing the body to recover from the illness.

Levofloxacin is considered a broad-spectrum antibiotic, which means it is effective against many different strains of bacteria. However, it does not work for viral infections, such as the common cold or the flu.

Common Side Effects

Many people using levofloxacin do not experience serious side effects. Common reactions may include:

• Nausea or vomiting
• Diarrhea or constipation
• Headache
• Dizziness
• Difficulty sleeping (insomnia)
• Stomach pain

Serious Side Effects

Levofloxacin can cause serious side effects that may be permanent. Seek medical attention immediately if you experience:

• Tendon problems: Pain, swelling, or inflammation in the tendons, which can lead to a tendon rupture.
• Nerve damage: Numbness, tingling, burning pain, or weakness in the hands or feet (peripheral neuropathy).
• Central nervous system effects: Seizures, tremors, hallucinations, anxiety, confusion, or depression.
• Heart rhythm changes: Fast or irregular heartbeat (QT prolongation).
• Severe allergic reactions: Rash, hives, swelling of the face or throat, or difficulty breathing.
• Severe diarrhea: Watery or bloody stools, which may indicate a Clostridioides difficile infection.
• Blood sugar changes: Very low blood sugar (hypoglycemia), which can lead to loss of consciousness.
• Sun sensitivity: Severe sunburn or skin blistering after exposure to sunlight or tanning beds.

Boxed Warning: Serious Adverse Reactions

Levofloxacin is associated with disabling and potentially irreversible side effects that can occur simultaneously. These include tendinitis and tendon rupture, peripheral neuropathy (nerve damage), and central nervous system effects such as seizures or hallucinations. These reactions can occur within hours to weeks after starting the medication.

Aortic Risks

There is an increased risk of ruptures or tears in the aorta, the body's main artery. This risk is particularly significant for individuals with a history of blockages or aneurysms, high blood pressure, or certain vascular disorders.

Blood Sugar and Mental Health

The medication may cause severe disturbances in blood sugar levels, including hypoglycemia that can lead to a coma. It is also linked to mental health side effects such as agitation, delirium, disorientation, and memory impairment.

Myasthenia Gravis

Levofloxacin may exacerbate muscle weakness in patients with myasthenia gravis. Use is typically avoided in individuals with a known history of this condition.

Additional Precautions

• Hypersensitivity: Serious and sometimes fatal allergic reactions can occur, even after a single dose.
• Hepatotoxicity: Severe liver damage has been reported in some cases.
• QT Prolongation: The drug may affect the heart's electrical rhythm, increasing the risk of arrhythmias.
• Photosensitivity: Increased sensitivity to light may result in severe skin reactions or sunburn.
• Clostridioides difficile-Associated Diarrhea: Treatment can alter the normal flora of the colon, leading to overgrowth of bacteria that cause severe diarrhea.

Pregnancy

The safety of levofloxacin during pregnancy has not been fully established in human studies. Research in animals has shown that fluoroquinolones, the class of antibiotics to which levofloxacin belongs, may cause damage to the developing cartilage and joints of a fetus. Because of these potential risks, healthcare providers typically only prescribe levofloxacin to pregnant individuals when no safer alternative is available and the treatment is considered essential for the mother's health.

Breastfeeding

Levofloxacin is known to pass into breast milk. There is a concern that the medication could cause serious adverse reactions in nursing infants, particularly related to the development of joints and bones. If you are breastfeeding, your doctor will help you decide whether to stop nursing while taking the medication or to use a different antibiotic. This decision depends on how necessary the medication is for the mother and the potential risks to the infant.

It is important to discuss your pregnancy status or breastfeeding plans with your healthcare team before starting treatment with levofloxacin.

Oral Forms

Levofloxacin is most commonly prescribed as an oral tablet. For patients who have difficulty swallowing pills or require specific liquid measurements, it is also available as an oral solution.

Injectable Forms

This medication is available as an injection for intravenous (IV) use, which is typically administered by a healthcare professional in a medical setting. The injectable form is supplied in two ways:

• Single-dose vials: A concentrated solution that must be diluted before it is administered.
• Premixed containers: A solution that is already diluted in a flexible plastic container and is ready for infusion.

The choice of form depends on the severity of the infection and the patient's ability to take medication by mouth.

FDA Approval and Indications

Levofloxacin is approved by the U.S. Food and Drug Administration (FDA) to treat a variety of bacterial infections in adults. Common indications include community-acquired pneumonia, acute bacterial sinusitis, acute worsening of chronic bronchitis, skin infections, and urinary tract infections. It is also approved for the treatment and post-exposure prevention of plague and inhalational anthrax.

Boxed Warning

The FDA has required a boxed warning for levofloxacin because it is associated with serious, disabling, and potentially irreversible side effects that can occur together. These include:

• Tendinitis and tendon rupture: This risk is increased in patients over 60 years of age, those taking corticosteroid drugs, and recipients of kidney, heart, or lung transplants.
• Peripheral neuropathy: Nerve damage that may cause pain, burning, tingling, numbness, or weakness in the arms or legs.
• Central nervous system effects: These may include seizures, hallucinations, anxiety, depression, and suicidal thoughts.

Because of these risks, the FDA advises that levofloxacin should only be used for sinusitis, bronchitis, or uncomplicated urinary tract infections when no other treatment options are available.

Additional Safety Communications

The FDA has issued safety communications regarding other serious risks associated with fluoroquinolones like levofloxacin:

• Aortic Aneurysm: There is an increased risk of tears or ruptures in the aorta, the main artery of the body. This risk is higher in patients with a history of aneurysms, high blood pressure, or certain genetic disorders.
• Blood Sugar and Mental Health: The FDA strengthened warnings in 2018 regarding the risk of severe low blood sugar (hypoglycemia) and mental health side effects, such as agitation or memory loss.

FDA Boxed Warnings

Levofloxacin carries an FDA Boxed Warning, the most serious type of warning, because it is associated with disabling and potentially irreversible side effects that can occur together. These include:

• Tendinitis and Tendon Rupture: Increased risk of inflammation or tearing of the tendons, especially the Achilles tendon. This risk is higher in patients over 60, those taking corticosteroid drugs, or those with kidney, heart, or lung transplants.
• Peripheral Neuropathy: Nerve damage in the arms or legs that can cause pain, burning, tingling, numbness, or weakness.
• Central Nervous System Effects: Risks include seizures, increased pressure in the head, dizziness, tremors, and psychiatric adverse reactions such as hallucinations or anxiety.
• Myasthenia Gravis: Levofloxacin may worsen muscle weakness in people with this condition and should be avoided by those with a history of the disorder.

Usage Restrictions

The FDA advises that for certain common infections, the risks of fluoroquinolones like levofloxacin outweigh the benefits if other treatment options are available. These conditions include:

• Uncomplicated urinary tract infections (UTIs)
• Acute bacterial exacerbation of chronic bronchitis
• Acute bacterial sinusitis

Additional Safety Alerts

The FDA has also issued warnings regarding the risk of aortic aneurysm (a bulge or tear in the main artery) in certain at-risk populations. Additionally, the agency has updated labels to include risks of significant disturbances in blood sugar levels, including life-threatening hypoglycemia, and mental health side effects such as agitation, delirium, and disorientation.