Patients taking Zithromax for relatively run-of-the-mill bacterial infections may not realize the risk of Stevens Johnson Syndrome associated with that medication.

Zithromax is pharmaceutical manufacturer Pfizer Inc.’s brand name for azithromycin. It’s now approved by the FDA to treat a wide variety of bacterial infections such as bronchitis, sinusitis, skin infections like Staphylococcus aureus, and infections of the genitourinary system.

Zithromax was originally approved by the FDA in November 1991. Since then it’s become one of the best-selling antibiotics in the U.S. Sales of Zithromax in 2011 reached $464 million, according to one report.

Part of Zithromax’s popularity may be attributed to its comparatively short course and convenient dosing schedule. Since azithromycin has a relatively long half-life – that is, the amount of time it stays active in the patient’s body – it can be administered with fewer doses. That feature allows for effective dosing using small 3- and 5-day course packs, which are branded as Z-Paks.

Azithromycin is also available in a one-time dose under the brand name Zmax. Studies show that a single Zmax dose can be as effective as a seven- to ten-day course of other treatments.

Zithromax SJS Complications

Although its a widely prescribed medication, Zithromax, Z-Paks and Zmax all bring with them the same risk of severe skin side effects such as Stevens Johnson Syndrome.

The current FDA-approved labeling for Zithromax refers to this risk in the Warnings and Precautions section, stating that cases of Stevens Johnson Syndrome and its related condition Toxic Epidermal Necrolysis have been reported in conjunction with courses of azithromycin. While both SJS and TEN are rare conditions, when they do occur they are severe and can be life-threatening.

Both SJS and TEN have systemic effects throughout the body, but their trademark features are the ways in which they attack the skin. After a few days of initial symptoms like cough, fever and body aches that can be mistaken for signs of the flu, SJS and TEN begin to manifest as a rash that breaks out over the torso and face. The rash spreads over the body, and as it does blisters begin to form in the middle of the affected areas.

These blisters grow into large areas of the outer layer of the skin that come loose and peel away. In SJS, between 10 percent to 30 percent of the body’s surface area is affected this way; in TEN, more than 30 percent is affected.

Other SJS and TEN symptoms have been known to attack other parts of the body. The mucous membranes can develop lesions similar to those attacking the outer skin. This can result in difficulty swallowing, painful urination, or sometimes gastrointestinal symptoms like chronic diarrhea. They may also develop conjunctivitis in the eyes.

These conditions can also lead to complications that can be permanently debilitating or sometimes fatal. The loss of skin can expose the body to infection, potentially triggering a state of sepsis. Eye symptoms may lead to tissue damage and possibly permanent blindness. Even after SJS and TEN resolve, the skin may be left with permanent scarring or discoloration.

While both SJS and TEN are rare, they are more often than not caused by a drug like Zithromax. Zithromax SJS can leave the patient with burdensome medical expenses and lost income in addition to painful and potentially debilitating residuals.