Lupron vs Zoladex

Zoladex is a synthetic hormone that stops testosterone production in men, and decreases the production of estradiol (a form of estrogen) in women.  Zoladex is approved for treatment of advanced breast cancer in pre- and peri-menopausal women. 

Lupron is a gonadotropin-releasing (GnRH or LH-RH) hormone agonist, meaning that it stops LH-RH in women from sending the signals the ovaries need to maintain a monthly cycle.  Lupron is not officially approved for treatment of breast cancer--it is used "off label" for that purpose.  Both drugs stop the menstrual cycle, and it is possible to get pregnant while taking either one.  Both will damage a developing fetus. 

Lupron has a longer side effect list than Zoladex.  Lupron can be given daily, monthly, every 3 months or every 4 months.  Zoladex is given every 28 days or every 3 months.

Lupron has been around a lot longer, so docs may be more familiar with it and more used to using it.  Some docs are not comfortable using a drug 'off label' and so prefer Zoladex.  Sometimes the choice depends on the timing--I live 2 hours away from my onc, so an every 4 month medication is a bonus, although not a big deal compared to every 3 months.  My onc was pretty up front--in her experience women have fewer problems with lupron than zoladex, despite the longer side effect list.  So the choice isn't always scientific. 

You can get a lot of good info about many drugs at MedicinePlus Drug Information:  http://www.nlm.nih.gov/medlineplus/

just type the name of the drug in the search box.

Pam-

my first thought is that the side effects wouldn't be much different since the amount of medication released into the system is about the same either way.  But that is my logical assumption, and we all know just how little logic applies to medicine in general and bc in particular!   I also can't see where there would be a benefit of monthly vs 3 monthly injections, except in the beginning, if the side effects were intolerable you wouldn't have to wait 3 months for the medication to work out of your system.  That being said, my first lupron shot was the 4 month dose, so I guess that is a question for the doc.  I don't know how much of my experience with lupron applies to your experience with zoladex. I think we would all be rather surprised how often our docs' choice of medication is based on past experience or some other factor than scientific data. 

the side effects with the 3 months won't be more, but if you can't tolerate the medication you have to wait 3 months for it to get out of you system. My doctor started me on 1 month to see how I tolerate Lupron and if I do, then I am going to switch to the 3 month formulation.