RE: (An interesting case of testis pain) - Methotrexate

Androlog Mail

{Regarding Methotrexate and spermatotoxicity:}

We found that single doses of 200 mg/kg (about 600 mg/M2, which in human
is about 18 mg/kg) produced reductions of sperm counts in mice (Meistrich
et al., 42 122-131, 1982). How does that relate to the doses this patient
is receiving? Since it is an inhibitor of nucleotide biosynthesis, it
killed some of the proliferating spermatogonia, which were killed (but we
don't know if they could have sustained mutations or died by apoptosis).
Although methotrexate is not considered to be as highly mutagenic as other
anticancer drugs, DNA damage, chromosomal and gene mutations have been
observed in men occupationally exposed to methotrexate:
Deng H. Zhang M. He J. Wu W. Jin L. Zheng W. Lou J. Wang B. Investigating
genetic damage in workers occupationally exposed to methotrexate using
three genetic end-points. [Journal Article] Mutagenesis. 20(5):351-7, 2005
Sep.

However the big risk is the teratogenicity of methotrexate, if any is
transferred via the semen. It is highly teratogenic and actually is used
in combinations for induction of abortions. He should therefore not
attempt a conceptrion while taking methotrexate (perhaps it may be OK
after the drug is cleared).

All in all, the use of cryopreserved sperm seems like the better option.
Hope this is helpful

Marvin L. Meistrich, Ph.D.
Professor of Experimental Radiation Oncology
University of Texas M. D. Anderson Cancer Center
e-mail: meistrich@mdanderson.org
Received on Thu Jan 4 08:05:31 2007