Fluoroquinolones such as Cipro, Levaquin & Avelox are intended to kill or stop the growth of certain bacteria. This family of antibiotics was first discovered in the 1960s, but it wasn’t until the late 1980s that Cipro and other modern fluoroquinolones first hit the market. At the time, doctors primarily prescribed them to treat urinary tract infections. Since then, they have become the go-to antibiotic for many infections.
These drugs are potent and are approved for the treatment or prevention of serious bacterial infections including anthrax, plague and bacterial pneumonia.
Other approved uses include the treatment of:
- Skin and skin structure infections
- Bone and joint infections
- Complicated intra-abdominal infections
- Infectious diarrhea
- Typhoid fever (enteric fever)
- Uncomplicated cervical and urethral gonorrhea
- Chronic bacterial prostatitis
- Lower respiratory tract infections
- Urinary tract infections
- Acute uncomplicated cystitis
- Acute bacterial sinusitis
- Acute pyelonephritis
- Acute bacterial exacerbation of chronic bronchitis
- Acute bacterial sinusitis.
A U.S. Food and Drug Administration (FDA) safety review found fluoroquinolones are associated with disabling side effects involving tendons, muscles, joints, nerves and the central nervous system. These side effects can occur hours to weeks after exposure to the drugs and may potentially be permanent, according to the agency. For that reason, the FDA has announced that patients with acute bacterial sinusitis, acute exacerbation of chronic bronchitis and uncomplicated urinary tract infections should only use fluoroquinolones when no alternative treatment options exist.
As with other antibacterial drugs, fluoroquinolones do not treat viral infections such as colds, flu or bronchitis in people who are otherwise healthy. They should be used “only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria,” according to the drug’s label. This is to reduce the development of drug-resistant bacteria and to maintain the effectiveness of fluoroquinolones and other antibacterial drugs.
Types of Fluoroquinolones
Six fluoroquinolones are currently available in the U.S. They can be administered in pills, injections and topical creams. Generally, fluoroquinolones are broken down into two categories: the older group (ciprofloxacin, norfloxacin, ofloxacin) and the newer group (gemifloxacin, levofloxacin, and moxifloxacin).
The most popular drugs in the class are:
- Cipro and Cipro XR (ciprofloxacin)
- Avelox (moxifloxacin)
- Levaquin (levofloxacin)
Other fluoroquinolones exist such as Floxin (ofloxacin) and Factive (gemifloxacin) but are not as widely used. Maxaquin (lomefloxacin), Raxar (grepafloxacin hydrochloride) and Zagam (sparfloxacin) are no longer available in the U.S. Noroxin (norfloxacin) was discontinued by its manufacturer, Merck.
Cipro, Cipro XR, Proquin XR (ciprofloxacin) Uses & Dosages
Cipro is the most widely used of all the fluoroquinolones, making up about 66 percent of all prescriptions each year. Some 21 million Americans take this drug annually. It was originally approved in 1987 and is a second-generation fluoroquinolone. Doctors often prescribe it to treat mild-to-moderate respiratory and urinary tract infections, but it also treats other conditions, including gonorrhea, infectious diarrhea and anthrax.
Cipro comes in the following formulas and doses:
Oral Tablets: 100 mg, 250 mg, 500 mg and 750 mg
Extended-release tablets: 500 mg and 1,000 mg (available only as generic)
Intravenous: 200 mg to 400 mg
Oral Suspension: 5% Oral Suspension: 250 mg ciprofloxacin per 5 ml after reconstitution; 10% Oral Suspension: 500 mg ciprofloxacin per 5 ml after reconstitution
Levaquin (levofloxacin) Uses & Dosages
Levaquin is the second-most-popular drug in the class, accounting for more than 28 percent of all prescriptions. It is a third-generation fluoroquinolone, originally approved in 1996. In 2010, it was the best-selling antibiotic in the U.S. Like Cipro, it treats respiratory and urinary tract infections. It also treats other conditions, including plague, anthrax, bronchitis and pneumonia.
Levaquin comes in the following formulas and doses:
Oral Tablets: 250 mg, 500 mg and 750 mg
Oral Solution: 25mg/mL
Intravenous: 250mg/50mL, 500 mg/100mL, 750mg/150mL
Avelox (moxifloxacin) Uses & Dosages
The third-most-popular fluoroquinolone in the U.S. is Avelox, a fourth-generation medication. The number of Avelox prescriptions dropped 78 percent from 2.7 million prescriptions in 2010 to 609,000 prescriptions in 2014. The FDA approved the drug in 1999 to treat multi drug-resistant types of Streptococcus pneumoniae – bacteria that cause pneumonia, ear infections and meningitis, among other conditions. It also treats skin infections, cellulitis and intra-abdominal infections.
Avelox comes in the following formulas and doses:
Oral Tablets: 400 mg
Intravenous: 400 mg
Factive and Floxin account for about 0.0005 percent of the total number of prescriptions for the class. Noroxin, Maxaquin, Raxar and Zagam are no longer on the market in the U.S.
- Factive — available in 320mg tablets and treats chronic bronchitis and pneumonia.
- Floxin — available in 200, 300 and 400mg tablets. This drug is more toxic than others in its class and often causes adverse events in patients.
- Noroxin — discontinued in 2014 for unclear reason. It was available in 400mg tablets to treat sexually transmitted diseases and urinary tract infections.
- Maxaquin — no longer available in the U.S., though it may still be used in generic versions.
- Raxar — withdrawn from the market in 1999 because it was shown to cause adverse cardiac events.
- Zagam — withdrawn from the market in 2001 because of phototoxicity and cardiac events.
Side Effects of Cipro, Levaquin and Avelox
Over the years, the FDA has received reports of life-changing adverse events in patients who have taken fluoroquinolone antibiotics. The most severe side effects of fluoroquinolones are considered rare. Some can be fatal. Common side effects of fluoroquinolones include headaches, lightheadedness, nausea, diarrhea, dizziness and trouble sleeping.
Potential serious side effects involving, tendons, muscles, joints, nerves, the central nervous system, the heart and other body systems include:
- Swelling or inflammation of the tendons
- Tendon rupture
- Tingling or pricking sensation (“pins and needles”)
- Numbness in arms or legs
- Muscle pain
- Suicidal thoughts
- Abnormally rapid or irregular heartbeat
- Ringing or buzzing in the ears
- Vision problems
- Skin rash
- Sensitivity of skin to sunlight
- Worsening of myasthenia gravis
- Aortic aneurysm
- Aortic dissection
Black Box Warnings
When the FDA determines that an approved drug carries significant risks, the agency requires that drug manufacturers add a black box warning to the product. This allows both doctors and users to become aware of the risks associated with using the medication. A black box warning is a serious step — just one away from removing a medication from the shelves.
Studies show people who have taken fluoroquinolones to treat infections may be at risk for developing life-altering side effects such as tendon and permanent nerve damage. The FDA has added and enhanced black box warning information to fluoroquinolone labels since 2008 as new risks have come to light.
The FDA concluded that fluoroquinolones are associated with tendinitis and tendon rupture. The agency notified drug makers that they needed to add a warning to all fluoroquinolone medication information, outlining the increased risk of developing these conditions.
The FDA added to the black box warning the risk of worsening symptoms of myasthenia gravis, a long-term neuromuscular disease that leads to varying degrees of muscle weakness.
The FDA added a warning to fluoroquinolone labels for a form of permanent nerve damage called peripheral neuropathy.
Following a 2015 FDA advisory committee meeting where experts discussed the dangers of fluoroquinolones, the FDA added another warning. In May 2016, the agency had advised doctors to avoid using fluoroquinolones in patients with acute bacterial sinusitis, acute exacerbation of chronic bronchitis and uncomplicated urinary tract infections. Fluoroquinolones should be reserved for these conditions only when there are no other options available. In July, the FDA mandated this labeling addition.
Other Problems Associated with Fluoroquinolone Antibiotics
Due to the expanding number and severity of fluoroquinolone-related problems, medical professionals can now diagnose Fluoroquinolone-Assisted Disability (FQAD) in patients. Individuals with FQAD are defined as U.S. patients who were reported to be previously healthy and have suffered debilitating side effects from fluoroquinolone use. What’s more, FQAD sufferers are patients who have been given fluoroquinolones when their conditions could have been cured with a far less powerful medication.
The diagnosis of FQAD was established in order to organize the diverse list of problems that can result from using these drugs. In addition to aortic aneurysm and peripheral neuropathy, the list of problems that can result from taking fluoroquinolones includes kidney disease and toxicity. What’s worse, the FDA has published safety alerts, notifying the public that the drugs are over-prescribed and are too risky for certain uses.
In 2013, the FDA released a Safety Communication warning about over-prescribing fluoroquinolones and said current warnings were not clear enough. Specifically, the agency said “the potential rapid onset and risk of permanence were not adequately described,” and the “permanent damage among patients exposed to these medications cannot be calculated.” Then in 2016, the FDA announced that fluoroquinolones were too risky for use in minor infections such as uncomplicated urinary tract infections. However, many doctors have not updated their prescribing practices accordingly, and some researchers say fluoroquinolones are still over-prescribed for minor issues like earaches and sinusitis.
Doctors Speak on Fluoroquinolones
Infectious disease physician Dr. Lindsey R. Baden told Consumer Reports that doctors tend to overprescribe fluoroquinolones because the drugs are effective against many bacteria.
Dr. Mahyar Etminan, an epidemiologist at the University of British Columbia, told The New York Times that overusing these drugs is like “trying to kill a fly with an automatic weapon.”
Dr. Jay S. Cohen, an author and professor of psychiatry who discussed preventing medication side effects, spent years detailing the dangers of fluoroquinolones, which he called the “worst medication disaster in U.S. history.”
In a 2013 study, American and Canadian researchers teamed up to explore the risk of kidney disease in users of fluoroquinolone antibiotics. They found the risk of acute kidney injury is doubled in people who are currently taking fluoroquinolones, especially ciprofloxacin and moxifloxacin. This condition requires hospitalization and often involves expensive renal care and multiple follow-up visits.
These drugs have also been linked to fluoroquinolone toxicity. This uncommon condition occurs in people who have adverse reactions to even small amounts of fluoride, a primary building block of fluoroquinolones. Toxicity is often detected when patients visit their doctors and complain about musculoskeletal symptoms such as hip pain. There is no medically recognized syndrome associated with fluoroquinolone toxicity.
Emily Miller holds five Health Literacy certificates from the Centers for Disease Control and Prevention as well as a Bachelor of Science in Journalism from the University of Florida. She is a member of The Alliance of Professional Health Advocates, the American Association for the Advancement of Science and the Society for Technical Communication. Emily was diagnosed with a chronic illness as a child and has firsthand experience with many of the topics she writes about as a member of the Drugwatch team. She is an award-winning journalist who has reported on health and legal news for reputable organizations, including the South Florida Sun Sentinel, San Antonio Express-News, UF Health News and Reporters Committee for Freedom of the Press. She draws on her background as both a patient and a journalist to help readers understand complex health and legal topics.