Posted by bulldog2 on January 3, 2007, at 13:59:41
This was written by a doctor on another site.Combining anticonvulsants with your meds may be reducing their effectiveness.
Certain substances, particularly some anticonvulsant medications, are known as "enzyme inducers". Such substances speed up certain liver enzymes which break down medications and other substances, including hormones. Examples include Carbamazine (Tegretol), Topiramate (Topamax), Oxcarbazepine (Trileptal), Phenytoin (Dilantin), Phenobarbital (a barbiturate), and Lamotrigine (Lamictal - albeit for most people weakly). These induce the liver to get ride of some reproductive hormones faster. Women on birth control pills, particularly, have to be aware of the interaction since an unplanned pregnancy may be the result.
Not all anticonvulsant medications have such an interaction. Valproic Acid (Depakote), for example, is known as an "enzyme inhibitor" - it slows down the break down of some substances or medications. Gabapentin (Neurontin) has no such liver interaction. Zonisamide (Zonegran) is another example. The liver induction also varies from person to person. For example, in the cited medline abstract, Lamictal did not show a reduction in testosterone for the men tested. However, since it does induce liver enzymes mildly, such as result may vary depending on the particular person. Off the top of my head, Pregabalin (Lyrica) may also be an anticonvulsant that does not induce liver enzymes (though I would have to check the PDR to check on this).
Anticonvulsant medications do reduce cognitive functioning as they work to reduce brain activity known as seizures. They reduce a person's I.Q. a bit, depending on the dose. This may itself reduce libido, change mood, etc.
poster:bulldog2
thread:718931
URL: http://www.dr-bob.org/babble/20070101/msgs/718931.html