The Journal of the American Academy of Dermatology released an article in the early 2000s detailing the potential risk of life-threatening reactions like Stevens Johnson Syndrome associated with the antibiotic Cipro.

Cipro (Ciprofloxacin) belongs to a family of antibiotics called the quinolones or fluoroquinolones. This family of antibiotics is synthetic in origin, while most earlier antibiotics were either naturally compounds produced by fungi or bacteria or derived from natural compounds.

When quinolones were first developed in the early 1960s, it was hoped that since they were synthetic, bacteria would have a harder time developing a resistance to them. While quinolones have not proven resistance-proof as hoped, they have joined other classes of antibiotics as staple drugs in the fight against infection. However, evidence has accumulated that Cipro could possibly cause a life-threatening reaction.

Stevens Johnson Syndrome or SJS is a type of autoimmune reaction, a reaction wherein the body attacks its own tissue, mistaking it for an invading germ. In the case of SJS, the body attacks the skin, causing a painful rash and flu-like symptoms. The rash can cover the whole body and include painful and debilitating sores and ulcers. The damage can also spread to the eyes and even the surfaces of the internal organs, leading to blindness and organ damage. SJS can be fatal.

The most extreme cases of SJS can escalate to an even more deadly reaction called Toxic Epidermal Necrolysis or TEN. TEN causes patches of skin to die and slough off, leaving burn-like wounds. Patients with TEN face many of the same complications seen in burn patients, including dehydration, secondary infection, and hypothermia, since the skin normally protects against moisture loss, infection, and heat loss.

Nearly all cases of SJS and TEN can be traced back to drug exposures. A wide variety of drugs have been linked to SJS and TEN, including antibiotics like Cipro. It is very difficult to predict which person will develop SJS from what drug. Even genetic testing, which has found some risk factors, is imperfect and does not work consistently.

The study in the Journal of the American Academy of Dermatology looked at data collected in Sweden between 1988 and 2000. According to this data, a handful of patients taking Cipro developed SJS. The reaction was certainly not common, but SJS is such a serious reaction that the study’s authors thought it was important to publish their results and make other physicians aware of this possibility. Physicians treating SJS sometime lose valuable days or hours in treating the reaction because the reaction is uncommon and the earliest symptoms mimic other diseases, like the flu. This means that the reaction can become more severe and harder to treat before the drugs causing the reaction are withdrawn.