Short-term prednisone, AVN link

October 1, 2007

While it is rare, avascular necrosis (AVN) is linked to even short-term prednisone use, and dermatologists should warn their patients about the possibility.

Toronto - The link between short-term prednisone use and avascular necrosis (AVN) remains somewhat controversial in the medical literature.

However, there is a clear association between short courses of the drug and the serious orthopedic condition in the eyes of orthopedic surgeons, lawyers, the courts and the Internet, according to Robert N. Richards, M.D., a clinical dermatologist and lecturer at the University of Toronto.

Dr. Richards became interested in the topic when he was among the healthcare providers sued when a 33-year-old man developed AVN after two short-term prednisone courses. After a decade in the courts, the case was dismissed. The judge ruled the treatment was appropriate given the condition and, in 1991 when the man received the prednisone, physicians did not know to warn patients of the possibility of AVN after short-term prednisone use.

A good drug

Prednisone is commonly used by physicians in numerous specialties.

Dermatologists frequently prescribe short courses of the treatment for severe and acute self-limiting conditions, such as contact dermatitis, eczema and hives.

"The most common dosage for short-term prednisone is usually starting at 40 mg to 60 mg, tapered or leveled over a few days, to a maximum of three weeks. The total of a short-term dose of prednisone by definition is up to about 600 mg-but most patients take about 400 mg or less," he says.

Side effects

While there are myriad well-established side effects from taking prednisone for the long term, short-term prednisone use is considered safe and effective, according to Dr. Richards.

Common and minor documented effects from taking the drug for the short term include sleeplessness, mood swings, anxiety, weight gain, stomach upset - even a feeling of euphoria. But there are also life-altering effects that can rarely occur with short-term prednisone. They are uncommon and unpredictable.

"This is not an issue to panic about. I use a lot of prednisone in the short-term, prescribing it three times in the last six or seven days," Dr. Richards says. "However, dermatologists and patients need to know that the more dangerous side effects from the drug exist."

Dr. Richards notes three serious side effects. With doses of more than 40 mg, there can be unpredictable psychological reactions, such as psychosis mania or depression, although such occurrences are rare.

There have been rare case reports of deaths in people who have taken prednisone while infected by varicella.

"It was thought for many years that these deaths with chicken pox and prednisone only happened to people who were immunoincompetent. But, in fact, there were a number of case reports of people who were immunocompetent," Dr. Richards says. "If dermatologists ever face a situation where there is any question, then these patients obviously need the antivirals for varicella while taking prednisone."

AVN and prednisone

Rarely, AVN, also known as ischemic necrosis, osteonecrosis (ON) or aseptic necrosis, occurs in association with short-term use of the corticosteroid. AVN is not bone thinning but rather refers to ischemia or a vascular interruption of blood flow, which results in necrosis and bone cell death.

It most commonly affects the hip joint and is usually bilateral.

While AVN can result from traumatic events to the joints, it also results from nontraumatic events, such as prednisone use.

People who have it often first notice bone pain in the affected joint with activity, which seems to subside with rest. Symptoms usually go gradually from pain and aching to stiffness and limited activity; then, to limited and painful hip rotation.