>1) Lupron (Leuprolide) is the same drug whether its in depot form
>or not. Many drugs now have a depot mechanism in which biochemical
>vessels (which are made of fats) can slowly release the drug into
>the bloodstream.
>
>2) This is important, because ALL drugs rapidly clear the blood through
>detoxification primarily through the liver. In Lupron's case its
>halflife is 2.9 hours! It means that in 3 hours half the drug remains.
>It doesn't mean the drug is no longer active. Usually drugs are rapidly
>taken in and converted to an active form, which has a longer term
>biological effect. How long this effect is totally depends on the drug.
>
>3) Bottom line: There is always a cyclic nature of drugs in terms of
>activity. The Depot form allows the tapering effect to occur much much
>later (months later) but it still occurs. Giving the drug every day
>allows rapid dose changes if necessary. Its probably also cheaper,
>but AFAIK there isn't an oral form of lupron available.

Yes, but for the 24 hour there is yet another consideration which can
be worse than just non-treatment:

http://www.miamiferret.org/fhc/24hr_lupron.htm

has info from John Hines, who studied Lupron and whose PhD is in
pharmacology:

> "... if the Lupron is of the type that all enters the bloodstream
>in 24 hrs., (24 hr. Lupron) what you get is a few hours of high
>pituitary activity followed by only several HOURS of inactivity
>(desensitized). Then the 24 hr. Lupron is gone shortly thereafter,
>and the pituitary RE-sensitizes and LH release to the natural GnRH
>resumes probably in a day or so. If the ferret is only getting the
>24hr. shot once a month, it's useless. In fact, the use of the 24
>hr. Lupron probably makes the adrenal disease worse because you
>don't get much therapeutic effect, but you are still getting that
>initial high pituitary activity when the Lupron is first
>administered. This initial burst of pituitary activity is of little
>consequence when it is followed by cessation of pituitary activity.
>But, with the 24 hr. Lupron, you get only the initial burst of
>pituitary high activity -- followed by normal pituitary activity.
>It's like adding a splash of gasoline to a fire."

Also, a vet's take:
http://ferrethealth.org/archive/SG9226
 and
http://ferrethealth.org/archive/SG7885

BTW, as has been mentioned before, many are noticing that the 4 month
depot seems to only last 3 to 3 and 1/2 months in ferrets. Those who
hadn't noticed the posts on that are asked to take note! Dr. Murray
asked me to carry this note for an FHL member to the FHL and I have his
permission to carry his FHL notes to the FML:

>Hi Sukie
>From the post it sounds like they are using the 2 mg, 4 month version
>of Lupron. There is speculation that it does not actually last for 4
>months and may only last for 3 to 3.5 months. Therefore it should be
>giving every 3 to 4 months, so it is actually time for the next dose!
>It definitely does not last for 6 months.
>
>It is also fine to give the melatonin implant a little early.
>
>Jerry

(Yahoogroups has the messages page lagging after mails by a few days.
No idea when they will fix that; they took all of Yahoogroups down for
a few hours once but the problem remained and the rift is growing wider
between day approved and when the messages section shows approved
posts.)

Sukie (not a vet)

Recommended ferret health links:
http://pets.groups.yahoo.com/group/ferrethealth/
http://ferrethealth.org/archive/
http://www.afip.org/ferrets/index.html
http://www.miamiferret.org/fhc/
http://www.ferretcongress.org/
http://www.trifl.org/index.shtml
http://homepage.mac.com/sukie/sukiesferretlinks.html

[Posted in FML 6124]