Medications like Cipro, Avelox and Levaquin are a type of antibiotic known as fluoroquinolones. These popular medications are used to fight many different types of infection but they may also cause serious side effects including heart problems and tendon rupture.
Fluoroquinolone antibiotics have been used to treat a wide range of infections caused by bacteria.
Some of the uses of fluoroquinolones include:
- Urinary tract infection
- Skin and soft tissue infection
- Sexually transmitted infection
- Bone and joint infection
- Infectious diarrhea
- Hospital-acquired infections
Fluoroquinolones have been highly effective at treating infection but may have serious side effects. Because of possible harmful effects on the heart, tendons, and nerves, the FDA has said quinolones should not be the first choice for treatment of common illnesses.
The fluoroquinolones are also sometimes called just “quinolones”. They were discovered during an attempt to make chloroquine, an anti-malarial drug, which accidentally created naldixic acid. It was approved in 1962 under the brand name, NegGram and was one of the only medications available to treat infections caused by Gram (-) negative bacteria.
Since the first quinolone, researchers have created thousands of analogs, only of few of which are available for use.
Fluoroquinolone medications approved in the U.S. include:
- Ciprofloxacin (Cipro, Proquin XR)
- Levofloxacin (Levaquin)
- Moxifloxacin (Avelox)
- Ofloxacin (brand name Floxin no longer available)
- Norfloxacin (Noroxin)
- Lomefloxacin (Maxaquin)
Several members of the quinolone antibiotic class were withdrawn from the market after approval because of toxic effects on the heart, liver, blood sugar or immune system, which may have caused multiple deaths.
By the mid-2000s, numerous cases of fluoroquinolone tendon injury were reported and had been linked to medication use. Fluoroquinolones were found to weaken the collagen structure of cartilage and increase the chance that the Achilles or other large tendons may break or “rupture”.
Studies indicated that fluoroquinolones are toxic to collagen I, which makes up most of the cartilage in large tendons. The drugs weaken collagen through “chelation”, by encouraging minerals such as calcium, magnesium or aluminum to stick to the cells. They may also interfere with cartilage repair by inhibiting enzymes or killing some of the cells needed to make new cartilage, known as chondrocytes.
Tendinopathy or tendon rupture risk may increase within days or even hours of taking a fluoroquinolone antibiotic and may be 3 or 4 times higher than normal. The risk is also higher in those over 60, organ transplant patients, or those taking anti-inflammatory steroids like prednisone. Fluoroquinolones should not be used in children unless medically necessary.
In 2008, the U.S. Food and Drug Administration issued a” black box warning” regarding the dangers of fluoroquinolones and tendon rupture. The FDA began requiring that manufacturers print information about the risk of tendon damage in a “black box” at the top of prescribing information for all fluoroquinolones. A black box statement is the most severe warning that can be given about a prescription medication. Manufacturers were also required to create a patient information guide about the risks.
Aortic Dissection and Aortic Aneurysm
Quinolones have also been associated with an increased risk of fatal cardiac complications. Two studies, published in 2015 in BMJ (British Medical Journal) and JAMA (Journal of the American Medical Association) found that recent use of fluoroquinolones (within the past 60 days) had double the risk for aortic dissection or aneurysm and that risk may extend for up to one year.
Both indicate that the drugs may damage cartilage in the aorta, the same way they cause tendons to rupture. The aorta is the large vessel which brings blood to the heart to be pumped to the body. It gets its structure from the same type of collagen that makes up cartilage in the Achilles and other tendons and may be weakened in the same way.
Aortic aneurysm occurs when the aorta wall begins to thin and bulge and if ruptured, massive bleeding will occur. Aortic dissection occurs when the inner layer of the aorta develops a tear. Blood may enter and separate, or “dissect”, the inner and middle layer and may burst the vessel in the same manner. In either case, a ruptured aorta may quickly result in death.
In 2015, an FDA advisory committee was called to evaluate the usage of fluoroquinolones in routine treatment of simple infections. The committee reviewed reports of tendon rupture, nerve damage, and cardiac events associated with fluoroquinolone use and determined that medications should not be used as a first choice for uncomplicated urinary tract infections, sinusitis and bronchitis.
In June 2016, prescribing information for all fluoroquinolones was changed to state that the medications should not be used if other treatments were available and to discontinue use if serious side effects occurred. Information about nerve damage or neuropathy was also added to the patient medication guide.
Common Fluoroquinolone side effects
Like all medications, fluoroquinolones may cause side effects like nausea but others may be more severe.
Side effects which may be more serious include:
- Allergic symptoms of rash, itching, facial swelling or difficulty breathing
- Watery diarrhea
- Tingling or unusual pain
- Changes in skin, urine or stool color
- Fast or pounding heartbeat
- Severe headache, dizziness or fainting
- Severe nervousness or anxiety
- Hallucinations, confusion, or unusual behavior
- Sudden pain or popping
- Swelling or fluid collection
Any of these symptoms may be serious and should be reported immediately.