What other substances might show up in a blood test for valproic acid levels?

July 25, 2009 6:17 AM

What other substances might show up in a blood test for valproic acid levels?

Asking for a friend:

Twenty-something female has been epileptic since she was a kid, and taking Depakote to control seizures. Her doctor ordered a fairly routine blood test to check for valproic acid levels, but since her last round of blood tests, she's gotten into the habit of smoking marijuana. She probably gets high once a week, on average, but sometimes more often. The lab order is written for a "Valproic Acid Level Test."

So on to the question: Is there any way to know whether her blood test for valproic acid might reflect her marijuana use? And if it does show up in a blood test, are there any legal repercussions? It seems like a valproic acid levels test shouldn't be looking for any other substances, and my instinct is that even if she tested positive for pot somehow, the doctor would just counsel her on the risks of drug use, but she'd like to know for sure.

Just FYI, she hasn't taken the blood test yet, but needs to schedule it in the next week or so.

Throwaway email at [e-mail] if there are any follow-up questions.

posted by anonymous to health & fitness (12 answers total)

Nothing else.

Unless the doc is secretly ordering other blood work. And I'm pretty sure the doc can't do anything legally about it unless she's another doctor or in some line of work where that would be important. Laws may vary.
posted by ruwan at 6:46 AM on July 25, 2009

There wouldn't be any legal repercussions even if the doctor somehow did notice marijuana in her system. Having been high in the past isn't possession.
posted by oinopaponton at 6:56 AM on July 25, 2009

I hate to be Grandma Disobedient, but her doctor should probably know if she's smoking once a week, especially if she's seizure-prone. They're not going to rat her out, they're going to provide council to ensure her physical well-being. Who knows, they might even have something intelligent to say on the matter.
posted by Civil_Disobedient at 7:10 AM on July 25, 2009 [7 favorites]

No, No, and for the love of god tell your doc about the drugs you're using.
posted by a robot made out of meat at 9:27 AM on July 25, 2009

Yes, good grief, it's really important for your doctor to know what chemicals are in your body, particularly when you're prone to seizures and on medication for epilepsy! It is not a doctor's job to judge you (or, your friend); it IS their job to keep you from dying and/or having seizures whenever possible.
posted by nosila at 3:18 PM on July 25, 2009

I think you've got to tell the doctor everything, so they can correctly evaluate whether it has any bearing on any current or future medical problems.

Having said that, my doctor is the type who jots down everything while I'm talking, right into my file. At one point, I needed to tell him something but didn't want an official record of it. I just asked, "Now, I'd like to tell you something, but I don't want it written down or put in my file ever." This worked. He didn't write it down, and it's not in my file, but he did say it was something that was important for him to know. So, maybe she could try this approach.
posted by Houstonian at 4:15 PM on July 25, 2009

With respect to the particulars of this case, there is no need for her to inform her doctor. There is no danger in combining Depakote with marijuana, and marijuana is actually a mild anticonvulsant. (I am epileptic as well.)
posted by kdk at 5:04 PM on July 25, 2009

kdk, did you make that diagnosis after a thorough review of her medical history, blood workup, other prescriptions, and other existing conditions? Doctors ask that you disclose even vitamins and over-the-counter medications, so I'm surprised at your medical advice.
posted by Houstonian at 6:00 PM on July 25, 2009

Houstonian, while all that is true, if you believe your doctor is taking that shopping list you give him and running through the expanded Krebs Cycle looking for stuff that might go wrong, I think you're being a little naive. Personally, I've heard enough "doctor prescribes two drugs that don't play well together" stories to question how often this sort of thing is considered.

Also, given that I get a form every time I go to a new doctor for any reason that assures me they won't share my medical information with anyone on Earth except for that copy they're still mailing to John Ashcroft for some reason I'd be real recalcitrant to tell my doctor anything I didn't want everyone and their dog to know about.
posted by Kid Charlemagne at 8:24 PM on July 25, 2009

That's true, and I too am concerned about the whole "war on drugs" issue (which is why I suggested she ask him to not document it), and the problem with doctors only spending a few minutes with each patient (which results in bad drug interactions among other things). But, if she is taking an anticonvulsant to control epilepsy (I assume it's epilepsy), then shouldn't her doctor know that she's taking another drug that also controls epileptic seizures?

And I guess I'm sensitive to people who are not doctors making definitive statements without saying the old "IANAD." There's a huge difference between "this is what I think based on my personal experience and the powers of google" and "this is my diagnosis, based on many years of studying the human body and working as a licensed physician." Even the doctors here are wary of making definitive statements, because they only have the information in the question, and no other information.

Since you (Kid Charlemagne) are a biochemist, I assume you are in a knowledgeable position to explain how testing works, at least in general terms, and whether or not it is likely that if she's tested for valproic acid they will somehow find marijuana. My guess is they will only find what they are looking for, but what is your expert opinion? How exactly does testing work?
posted by Houstonian at 5:21 AM on July 26, 2009

Houstonian: I simply claimed that there are no interactions between Depakote and marijuana per se, and marijuana poses no problems to the epileptic. That's all I said, and I stand by it. I made no diagnoses, I simply relayed some factual claims that I have learned after extensive research into epilepsy for my own sake. Of course it's the case that if she's on other meds or has other medical conditions, then those might be problematic and require disclosure, but that's a separate issue. The topic was about Depakote, marijuana, and epilepsy; I was simply pointing out that there is no problem with the particular combination that is at issue in this post.
posted by kdk at 5:24 AM on July 26, 2009

A test for this specific value is just that, a test for Valproic Acid levels (50-100 mgL is *typically* therapeutic from my understanding). THC or any other chemical is unrelated to the test as ordered. It'd be like ordering a screening for lung cancer & also finding genital warts. Agreed on informing her MD of the THC use- brain chemistry can be so unique, it's very helpful for her to be up front regarding anything that may effect the efficacy of the Depakote.
posted by moonbird at 9:32 PM on July 27, 2009