Re: WBC back in normal range

[Guest guest]

>

> Hello All,

>

> After a month and a half of worrying about my WBC rising, it is

back in the

> normal range today at 7.2. I had been trying to figure out how did

I go from

> " complete hematological remission " to an ever rising WBC? The

only thing

> that I was doing differently was the introduction of Tompamax to

battle the

> headaches I refer to as " Gleevaches. " Well, I stopped the Topamax

for the last

> two weeks and wa-la! WBC back in normal range. Is there a

correlation I

> asked? Could be? SO, I am going to stay off the Topamax and see

what happens.

That is great to hear!. I looked up Topamax and this drug is a

moderate inducer of the cytochrome P450 3A4 which is the primary

enzyme in the liver responsible for metabolizing Gleevec.

Drugs that induce 3A4 would have the effect of LOWERING your Gleevec

concentration in the blood and could result in levels of Gleevec that

are too low to control the growth of the CML cells. This does seem

to be the probable cause of your WBC increase.

Avoiding Topamax seems to be a good idea. I'd recommended consulting

with a Pharmacist, particularly one with Oncology experience, to come

up with another option if the headaches require continued treatment.

[Guest guest]

I'm so glad that you found the culprit and now know what to

avoid to ensure that your Gleevec is being metabolized ideally.

I'm a little disturbed though because according to www.drugs.com

(which I use all the time to look for interactions with Gleevec),

there is no mention of any interaction between Gleevec and Topamax.

Clearly there is an interaction (as Tim was so kind to point out) so

I'm now left wondering just how accurate www.drugs.com is and why it

didn't pick up this interaction.

Tracey

-- In , " " <timothyfarley16@...> wrote:

>

>

> >

> > Hello All,

> >

> > After a month and a half of worrying about my WBC rising, it is

> back in the

> > normal range today at 7.2. I had been trying to figure out how

did

> I go from

> > " complete hematological remission " to an ever rising WBC? The

> only thing

> > that I was doing differently was the introduction of Tompamax to

> battle the

> > headaches I refer to as " Gleevaches. " Well, I stopped the

Topamax

> for the last

> > two weeks and wa-la! WBC back in normal range. Is there a

> correlation I

> > asked? Could be? SO, I am going to stay off the Topamax and

see

> what happens.

>

>

> That is great to hear!. I looked up Topamax and this drug is a

> moderate inducer of the cytochrome P450 3A4 which is the primary

> enzyme in the liver responsible for metabolizing Gleevec.

>

> Drugs that induce 3A4 would have the effect of LOWERING your

Gleevec

> concentration in the blood and could result in levels of Gleevec

that

> are too low to control the growth of the CML cells. This does seem

> to be the probable cause of your WBC increase.

>

> Avoiding Topamax seems to be a good idea. I'd recommended

consulting

> with a Pharmacist, particularly one with Oncology experience, to

come

> up with another option if the headaches require continued treatment.

>

[Guest guest]

>

> I'm so glad that you found the culprit and now know what to

> avoid to ensure that your Gleevec is being metabolized ideally.

>

> I'm a little disturbed though because according to www.drugs.com

> (which I use all the time to look for interactions with Gleevec),

> there is no mention of any interaction between Gleevec and

Topamax.

> Clearly there is an interaction (as Tim was so kind to point out)

so

> I'm now left wondering just how accurate www.drugs.com is and why

it

> didn't pick up this interaction.

>

Thanks for that website Tracey. It seems quite comprehensive. The

entry for Topamax does note this:

" In vitro studies indicate that topiramate is a mild inhibitor of

CYP2C19 and a mild inducer of CYP3A4 "

I will go with the site's characterization as " mild " . Topamax's

effect on the 3A4 is much less than Rifampin which has been shown to

lower Gleevec levels between 54-74%.

It is known that Gleevec levels in the blood can vary quite a bit in

people taking it. Perhaps in Chris' case, the mild effect of Topamax

and a trend towards the low Gleevec levels " Might " be responsible.

Maybe this drug interaction is one of those " one in a million "

occurences "

[Guest guest]

Hi Tim and

I guess the lesson I've learned from this experience is that I can't

rely on the information using the " drug interaction checker " from

www.drugs.com, instead, I need to look each drug up individually and

see which isoenzyme it uses to metabolize. A bit of a pain, but in the

end, not a big deal when you consider the possible ramifications of

taking a drug that interacts negatively.

Tracey

[Guest guest]

I am so happy that things have gotten better for you!

As Tracey mentioned it's pretty discouraging to find out that the medicine

you were taking did not interact with Gleevec well and this could have

continued had you not decided to review the changes you made.

This should be reported to Novartis ASAP. Or at least Dr. Druker. Has any

one done so?

ez