Sticks and stones and crumbling
bones
Bisphosphonates appear to have
another rare but nasty side effect, according
to UBC and McGill researchers: bone death. Aseptic
osteonecrosis was three times as likely when patients
were taking a bisphosphonate, found the study
of a group of elderly Quebec cardiovascular patients
published online January 15 in the Journal
of Rheumatology.
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If you have an osteoporosis patient
suffering from severe and debilitating bone, joint and
musculoskeletal pain, you might want to rethink that
bisphosphonate you prescribed them. That's the message
the FDA is sending out to physicians in a January 7
release.
Pain associated with bisphosphonate
use is listed on the product monograph for these meds,
but incidence was extremely low in clinical trials.
Since then, the number of reports has grown to the point
that the FDA has decided to launch a review of the drug
class.
"It's not that uncommon," says
Dr Dave Hanley, an endocrinologist and osteoporosis
expert at the University of Calgary. "In my osteoporosis
clinic, I have a lot of patients on bisphosphonates
and I see about one person a month with this. This is
for real."
He says it's hard to know what
proportion of patients suffer these effects, but he
guesses about 2-5%. Though the FDA warning implies that
physicians aren't paying enough attention to these potential
side effects, Dr Hanley thinks it's pretty well-known
among his colleagues. "Certainly by bone specialists,
endocrinologists and rheumatologists," he says. But
he admits that it's possible to confuse the symptoms
with osteoarthritis pain.
When Dr Hanley has a patient on
a bisphosphonate who complains of sudden pain, the first
thing he does is try them on another bisphosphonate.
If the pain persists, he takes them off. "Most respond
to stopping the drug," he says. "If it doesn't settle
down, it was something else and the patient needs a
reassessment for musculoskeletal problems, polymyalgia,
rheumatica or fibromyalgia."
There's another really simple step
you should take: "I always encourage physicians to make
sure the patient's not vitamin D deficient that
can really amplify this," says Dr Hanley.
No one's really sure what's causing
the pain in this small number of patients. Dr Hanley
has a hunch they may be more sensitive to a bone mineralization
disorder. "This is purely speculative, but the use of
an intravenous bisphosphonate, like the once-a-year
zoledronate, might get around this," he says.
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