Teva Pharamceutical Industries, Ltd. has introduced a new generic equivalent to Actonel, a medication used to treat and prevent osteoporosis.

Actonel is Warren Chilcott LLC’s brand name for risedronate sodium. First approved by the FDA in March 1998, it is now approved for treatment and prevention of osteoporosis in postmenopausal women and of glucocorticoid-induced osteoporosis.

It’s also approved as a treatment for Paget’s disease and for low bone mass in men with osteoporosis. It tends to reduce the incidence of bone fractures related to osteoporosis.

According to Teva, about 54 million Americans suffer from low bone mass and osteoporosis. Annual sales of Actonel, the brand version of risedronate sodium marketed by Actavis, reach about $157 million.

Israel-based Teva Pharmaceutical is the world’s largest producer of generic medications, with a catalog of over 1,000 different products. Teva took in $20.3 billion in net revenue in 2014.

Risedronate, Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

Despite risedronate’s long history on the market and recent new FDA approval, it has been linked to some cases of debilitating side effects, one of which is Stevens-Johnson syndrome, or SJS.

SJS is a profoundly damaging condition that chiefly attacks the skin. Though it doesn’t happen often, when it does occur it is most likely caused by a medication, such as Actonel.

SJS typically begins with symptoms that resemble those of the flu — and because of that similarity it is often misdiagnosed at first. Common symptoms at onset are usually fever, body aches, headache, or cough. Soon a rash breaks out over the skin.

Within the areas of rash, blisters will begin to form. These blisters may grow and coalesce into large areas of skin that peel away. If the condition advances so that these blisters cover 30 percent of the body’s surface area, the condition is then referred to as toxic epidermal necrolysis, or TEN.

Significant loss of skin exposes the body to an increased risk of infection. In addition to areas of peeling skin, the patient’s hair and nails may fall out. Blisters may also form on the mucous membranes within the mouth, genitals, and eyes.

The mucous membranes of the digestive and respiratory systems may also be affected, compromising breathing and possibly causing diarrhea. Other eye symptoms are also common: the eyes may become painful, swollen and filled with pus.

Treatment for SJS and TEN requires hospitalization, sometimes in a hospital’s burn unit due to the similarity between SJS symptoms and those of severe burns. Treatment is mainly directed at relieving symptoms while the body is given a chance to heal itself. Some doctors administer corticosteroids, but others avoid that due to their tendency to weaken the immune system.

According to the Mayo Clinic, patients should see their doctor for possible SJS or TEN, if they start experiencing the following symptoms:

• Unexplained widespread skin pain
• Facial swelling
• Blisters on your skin and mucous membranes
• Hives
• Tongue swelling
• A red or purplish skin rash that spreads
• Shedding of your skin