Quinolone antibiotics, among the most commonly prescribed antibiotics, have been linked to complaints by users of peripheral neuropathy.

One of these victims was musician and personal trainer, David C. Before his injuries, he regularly played music and could run up to six miles a day. However, he claims that this changed after he was prescribed Cipro (Ciprofloxacin) to treat his colitis last year.

Soon after starting Cipro, David reportedly experienced severe nerve pain, a side effect not listed on the drug’s warning label. He says he started to feel extreme fatigue by just standing up, his ears started ringing, and had started to have trouble walking by the second month. He eventually was diagnosed with peripheral neuropathy.

In another recent case, Tammy R. was prescribed Levaquin to treat a sinus infection and started experiencing adverse effects after six days on the medication. She reported feeling heaviness in her thighs, pressure in her lower spine, and overall nerve pain.

Tammy described the pain as several of her vertebrae rubbing against each other, and said she could hear them snapping. Similar to Cipro, Levaquin’s warning label does not mention nerve damage or peripheral neuropathy.

Both patients say that they would not have taken their respective quinolone antibiotics if they knew the risks of peripheral neuropathy. They say they are considering lawsuits against the pharmaceutical companies, alleging that the companies failed to protect them against the dangers of their products.

Such cases are not rare. Thousands of quinolone antibiotic users have reported similar complications.

From November 1997 to May 2011, over 85,000 Levaquin injuries and over 67,000 Cipro injuries were reported to the FDA, which includes 1,174 deaths and 1,257 deaths respectively. According to Bayer Pharmaceuticals, the FDA issued a drug safety notification in 2013 to all quinolone manufacturing companies to update their labels to adequately describe the risk of peripheral neuropathy.

The quinolone drugs included in this warning include: Levaquin, Cipro, Moxifloxacin (Avelox), Norfloxacin (Noroxin), Ofloxacin (Floxin), and Gemifloxacin (Factive).

In August 2014, a study published in the medical journal Neurology found that taking these drugs could double the permanent risk of peripheral neuropathy. At this point, experts are unsure as to what causes peripheral neuropathy, but believe that the antibiotics could be inducing disruptions between the brain and spinal cord.

Periphal neuropathy occurs when nerves in the central nervous system become damaged or destroyed, which prevents signals from traveling between the spine and brain.

Peripheral neuropathy can cause permanent nerve damage, and tends to be rapid in progression. Quinolone patients who experience sudden aches, pains, or spasms are encouraged to talk to their doctors immediately.