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Gemzar, chemotherapy drugs. How long do they stay in the body ?

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how long does chemotherapy drug stays in the body

Posted Sat, 5 May 2012 in Cancer
Answered by Dr. Sujeet N Charugulla 2 hours later

Thanks for your query.

I shall make an effort to provide you with good professional recommendations specific to your questions.

If you are asking how long does your chemotherapy drug -Gemzar stay in the body - Gemcitabine.

Then, within 1 week 90-98% of the given dose gets excreted in urine. The excretion parameters vary with the type of infusion, length of infusion, sex, age. But, this does not mean the drug will do its job for whole 1 week, this excretion parameter is purely for urine clearance from the body. And the clinical effect of the drug would need adequate concentration of the same in the body. Hence repeat doses are timed suitably for achieving this.

The CA-19-9 levels in Cancer are of prognostic significance to the oncologist for the response to treatment. Serial tests are done to assess the patient's status. The levels drop with successful therapy.

Yet again, I duly appreciate your query to me, I do hope that you have found something useful to help you and I shall be glad to answer any further apprehensions.

Above answer was peer-reviewed by
Follow-up: Gemzar, chemotherapy drugs. How long do they stay in the body ? 2 hours later
can you see already results in CA19-9 for patients that had undergone chemo for 2 cycles? for 2 cycles of chemo the patient had been through what would you suggest if.
Aug.20 CA19-9: 3834
2 cycles of chemo in the middle
then on Sept 30: 8000
Answered by Dr. Sujeet N Charugulla 1 hour later

Thanks for the follow up query.

Two cycles of Gemcitabine over 4/5 weeks, in this situation, for 2 readings of CA 19-9 would not give the final picture for the Oncologist.

Usually, 2 months and above is the reference time interval during which many serial readings are compared against and checked to see the prognosis.

A decrease of values >20% is considered an adequate response. An increase / decrease < 20% is an indication for further intensive review.

Hence, although it a double increase in reading over 5 weeks in here, the complete meaning can be derived after a further 3 weeks or more.

Until then, do not derive any conclusions that your chemotherapy is not working.

I hope, I have answered your query.

Wish you good health.

Above answer was peer-reviewed by
Follow-up: Gemzar, chemotherapy drugs. How long do they stay in the body ? 1 hour later
aug. 20 when CA19-9 was done 3834 then he started his chemo of gemzar and oxaliplatin. 1st chemo was Aug. 30 then 2nd chemo was Sept. 20 then CA19-9 was again taken result was 8000
Answered by Dr. Sujeet N Charugulla 2 hours later

Thanks for writing again.

Yes, as you can see, count the days from Aug 30.

That makes Oct 30 or so beyond which prognostic value of the test starts.

Thanks and let me know if anything else concerns you.
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