Q: Osteoporosis & Anti-seizure Meds : Lamictal & General Itching
Related to the Dose|
I have two questions. I have searched the archives and not really found an
answer to either.
The first is about osteoporosis and/or bone loss. I'm taking lamictal 500mg and
topiramate 300mg, plus Wellbutrin xl 300mg. I have been on the topiramate for
over three years and just went on the lamictal one year ago and the Wellbutrin
four months ago to attempt to control continuing depression. I am depressive
bipolar II ultra ultra rapid cycling. I have read about long-term use of
anti-seizure medications contributing to bone loss and I'm wondering if that is
something I need to consider since I am hoping these medications will continue
to work for me long-term. I do take supplemental calcium and multiple other
vitamins due to having had a gastric bypass years ago.
My other question is about lamictal causing general itching related to the
dose. No rash, though. At 400mg I had no problems but when I went up to 600mg
(raised the dose over a couple of weeks) I was fine for about four weeks, then
started itching, mainly on my upper body. I went back down to 400mg and was
fine, back up to 600mg and the itching began immediately. I went back to 400mg
again and stayed there for a month, then went to 500mg and had a little itching
for a few days and have been afraid to raise my dose back up to where my
psychiatrist wants it again. The high dosage is to combat the lingering
depression and hopefully get rid of the Welbutrin.
Thanks for any information regarding either question!
Hello Laura --
1. Decreasing bone density (osteoporosis): you are right, there are concerns
about this issue and people taking anti-seizure medications for a long time.
Some of this concern has been fanned by the manufacturers of those medications
which appear not to be associated with this problem, one of which is lamotrigine
(Lamictal). For example, see this investigation from Denmark. Lamotrigine does
not appear to be a problem in this and other studies.
As the investigators there conclude, in general the concern is more with
antidepressants that are "liver enzyme inducers". This means that the
anticonvulsant somehow induces the liver to make more enzymes that chew up
things the liver metabolizes anyway, but in this case, it will do it faster. In
other words, the standard metabolic enzymes are kicked into a higher gear by
liver enzyme inducers. One of the compounds thus metabolized is estrogen, so
such anticonvulsants can lower estrogen levels. As you know, estrogen is
important for maintaining bone density in women.
Although in the study cited above topiramate did not quite reach statistical
significance for increasing bone fractures, there was a strong trend in that
direction. The topiramate is recognized as a "liver enzyme inducer" and is
usually included on a list of medications for which this concern is warranted.
If you are getting a great response to the topiramate, and want to keep it, then
you could talk with your doctor about getting a bone density study. On the other
hand, being overweight causes increases in bone density so before your gastric
bypass you might have laid in a significant bone stock that protects you against
osteoporosis. You and your doctor can discuss that.
2. Management of that itching you describe is really up to you and your
psychiatrist. It is not within the typical range of symptoms that we warn
patients about, regarding the severe rash that Lamictal can cause, but any such
phenomenon -- given the risk of the severe rash -- raises concern and warrants
very close monitoring at minimum. Make sure your doctor knows about this
Published November, 2007