Treating an infection with Zithromax is often a faster and more convenient route to recovery than treatment with other antibiotics. But patients may be surprised to learn how severe and sometimes dangerous Zithromax side effects can be.

Zithromax is a brand name for azithromycin, an antibiotic used to treat many different types of bacterial infections of the ears, skin, respiratory system, or sexually transmitted diseases.

It can often be administered in much shorter courses than can other antibiotics. For that purpose, azithromycin is sometimes packaged in a three- or five-day supply called a Z-Pak, or in a single large dose called Zmax.

Those shorter courses have helped make Zithromax pretty popular. Even with competition from generics, brand-name Zithromax accounted for $435 million in sales in 2012.

Zithromax Side Effects

Despite its popularity, though, Zithromax isn’t without its side effects. Some known Zithromax side effects can be particularly severe. A March 2013 warning from the FDA alerted the public to the risk of some potentially fatal cardiovascular Zithromax side effects.

The drug’s warning label also alerts users to Zithromax side effects that affect the skin. In addition to pruritus and erythema multiforme, Stevens Johnson Syndrome and its related condition Toxic Epidermal Necrolysis are two of the side effects listed.

Fortunately, these conditions are very rare. But when they do occur, both Stevens Johnson Syndrome and Toxic Epidermal Necrolysis can attack the skin and can expose the entire body to systemic complications.

Skin lesions are the signature symptom of Stevens Johnson Syndrome. These lesions begin as a rash that spreads across the body. Blisters appear within those areas of rash. These blisters grow into larger patches of skin that detach and peel away, exposing the sensitive lower layers.

Without the protective outer layer of skin, these exposed areas are vulnerable to developing a Zithromax skin infection. The mucous membranes or lungs may also become infected, and the patient may be at risk for developing septicemia, or blood poisoning. These infections are the most common cause of death for Stevens Johnson Syndrome patients.

The amount of skin affected this way is what makes the difference between Stevens Johnson Syndrome and Toxic Epidermal Necrolysis.

The two conditions are now considered different extremes of the same reaction. Toxic Epidermal Necrolysis affects more of the skin and has a higher mortality rate, reaching as high as 25 percent in adults and sometimes higher in groups of more vulnerable patients.

Sores may also also affect the patient’s mucous membranes, the soft tissue that lines the inside of the mouth, throat, eyes and genitals. The eyes may develop conjunctivitis, and scarring of the corneas sometimes leaves the patient blind.

In cases linked to Zithromax, treatment of Stevens Johnson Syndrome begins with discontinuing the antibiotic as soon as possible. Skin lesions may be treated with dressings and topical antiseptics to prevent Zithromax skin infection. Should such an infection develop, other antibiotics may need to be administered immediately.

Other uses of medication such as corticosteroids are still controversial, because no medications have clearly been demonstrated to improve patients’ survival rates.