Penmix 50 is Novo Nordisk's r-DNA/GE/GM human insulin mixconsisting of 50% R/neutral insulin and 50% NPH/isophane insulin. It consists of 50% isophane insulin crystals. It is the same as Humulin 50/50, Actraphane 50/50 Mixtard 50, and Insuman Comb 50. Eli Lilly produced a similar insulin in the EU & UK called Humulin M5; it was discontinued in July 2004 Mixtard 50 was discontinued December 31, 2007.