METHOTREXATE LIFE SPAN IN THE SYSTEM ?

andy2. I wish you well in your departure of the use of methotrexate.I know this is an old post but it was a good question. I was curious myself. A google search and Pharmacological reviews website says" The half-life of methotrexate in the serum is in the range of 6 to 8 h after administration of the drug and is undetectable in the serum by 24 h (Fossa et al., 1988; Kozloski et al., 1992; Oguey et al., 1992; Jundt et al., 1993; Lebbe et al., 1994; Bannwarth et al., 1996). Methotrexate is taken up by cells and polyglutamated and methotrexate polyglutamates, likely the active compounds, are long-lived (days to months) in the tissues (Kremer et al., 1986; Dervieux et al., 2003)." probably something usefull for anybody to know before starting the drug. 

Well, in order to have a baby you have to be off it for 3 months, so you should be totally clear by 7. 

Drugs.com Pregnancy should be avoided if either partner is receiving MTX, during and for a minimum of 3 months after therapy for male patients, and during and for at least 1 ovulatory cycle for female patients. This drug has been successfully used to terminate tubal pregnancy. Woah! a topic in itself.

Hopefully you've found the answers you were looking for, but if not, Wheato and Todd were correct. I was on both sides of the issue. My wife's first pregnancy was terminated due to a rupture in her uterine wall. They used MTX to terminate. A year later I was diagnosed with RA, polymyositis, and fibromyalgia. The doctor prescribed MTX. The name sounded familiar, and when I Googled it, I said, well ain't that the mother of all cruel coincidences. My wife and I decided to give it another go, and I asked my Rheumy how long do I have to be off of the drug. She advised 3 months, I gave it 6, increased my prednisone and flared almost constantly. The good news is I now have a 2 year old and a 2 month old. The bad news is now I have a 2 year old and a 2 month old. Lol.