Quinolones are a key element of physicians’ antibiotic arsenal, but a growing number of lawsuits allege that drug makers downplayed a serious risk associated with these drugs: nerve damage known as peripheral neuropathy.

Quinolones are a class of antibiotics developed in the 1960s. Quinolones, and their most popular sub-type, fluoroquinolones, were the first fully-synthetic family of antibiotics. All earlier groups of antibiotics were either produced by living things like bacteria and fungi or based on such compounds.

It was hoped that quinolone antibiotics’ artificial nature would help them avoid some of the problems seen in other antibiotics like antibiotic resistance. While quinolone antibiotics have not proven full proof against antibiotic resistance, they have proven to be a particularly effective group of drugs and have joined the ranks of important antibiotics. This includes drugs like Avelox, Cipro, and Levaquin. However, concerns have arisen that some patients may experience a particularly serious side effect from quinolone antibiotics: peripheral neuropathy.

Peripheral neuropathy is Latin for “damage to the outer nerves,” referring to the main process of the disease. In Peripheral neuropathy, nerves of extremities like hands and feet start to malfunction, and sometimes die, causing peripheral neuropathy symptoms.

Peripheral neuropathy symptoms include pain and numbness in the extremities. Often, one of the first peripheral neuropathy symptoms is a tingling in the effected area, similar to the feeling of a limb “falling asleep.”

Many patients taking quinolone antibiotics who went on to suffer from peripheral neuropathy suffer from cases classified as severe. And many cases of peripheral neuropathy may be permanent, since nerves do not regenerate as readily as some other tissues within the body.

New quinolone antibiotic lawsuits have begun to allege that drug companies bear a responsibility for peripheral neuropathy. These lawsuits allege that drug makers have been aware of this risk—or reasonably should have been aware due to their legal obligations to monitor reports of new post-market complications.

Allegedly, research dating back to 1992 has demonstrated a link between quinolone antibiotics and peripheral neuropathy. Research studies have continued to mount suggesting that peripheral neuropathy can be a side effect of quinolone antibiotics, to the point that in 2013, the FDA mandated changes to the labeling of Avelox, Cipro, Levaquin, and several other common fluoroquinolones advising patients of this possible risk.

Additionally, peripheral neuropathy lawsuits may allege that drug makers were not only aware of these risks, but that deliberately downplayed these risks, continuing to aggressively market their drugs in spite of the alleged anger of peripheral neuropathy. Peripheral neuropathy lawsuits generally seek to recoup the cost of medical care, lost wages due to hospital time or disability, legal fees, and other cost allegedly caused by quinolone antibiotics.