Has anyone heard that the size of the needle is important in methotrexate injections? When asking for the smallest needle size available the pharmacist told me that she had been told that using a small needle would destroy the molecular structure in the drug by the action of "pushing" the drug's large molecules through a small opening. She said that ruined the drugs effectiveness by doing this and suggested that I never use small needles like the ones used for insulin. I have never heard this before and have been on it for quite some time.