Q. Kevod Harav. When one has to inject during Shabbat pain killers or insulin, does one have to be careful not to inject into a vein?
A. Horav Shlomo Miller’s Shlit’a opinion is that indeed one should be careful and avoid injecting directly into a vein or artery when not required, as drawing blood from them into the syringe may be a Biblical prohibition. The needle should go into muscle or other tissue when medically also recommended.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a