Norditropin Nordiflex (somatropin [rDNA origin] injection, Novo Nordisk) can now safely be stored unrefrigerated for up to three weeks after initial use, or refrigerated up to four weeks, according to the FDA. The product is designed as a long-term treatment of children with growth failure due to inadequate secretion of endogenous growth hormone and adults with growth hormone deficiency. The new storage instructions apply to the 5-mg and the newly available 10-mg pens. Before this, all growth hormone pens had to be stored in the refrigerator after initial use. The 15-mg delivery pen must still be refrigerated before and after the initial injection.