Zanaflex and breastfeeding

[UtahMomma]

Hi. I was diagnosed with MS in 08. I am currently nursing my 7 month old. I have been prescribed Zanaflex 4mg as needed. So far I have only taken them at night or when I knew I could give him a bottle for several hours. Do you have any information on this medication? I'm also on Avonex and was relieved that I could still breastfeed.
Thank you,
Kaitee

[cpride]

Dear Kaitee,

Tizanidine (Zanaflex) has two formulations. The conventional formulation has a half-life (time it takes for one-half of the drug to be excreted from the body) of 4 to 8 hours (hrs) while the extended release formulation has a long half-life of 13 to 22 hours. It takes five half-lives for a drug to be eliminated from the body. Waiting at least three half-lives should eliminate most risk. You should contact either your physician or your pharmacist to find out which formulation you are taking. For the conventional formulation, you should pump and discard for 24 hrs before resuming breastfeeding. For the extended release formulation, you should wait 2 and 1/2 days (66 hrs) before resuming breastfeeding. Interferon Beta 1A (Avonex) is a large molecule; therefore, transfers minimally into breastmilk. It is compatible with breastfeeding. Let me know if you have further questions.

Sincerely,
Cindy Pride, MSN, CPNP
TTUHSC InfantRisk Center