FDA Raises Impurity Threshold to Address Losartan Shortage

The FDA said it will allow drugmakers to sell losartan with higher levels of a potentially cancerous impurity over the next six months to prevent a shortage of the blood pressure drug.

Amid a wave of blood pressure medicine recalls, the agency says it’s willing temporarily to allow losartan products onto the market with N-Nitroso-N-methyl-4-aminobutryic acid (NMBA) levels below 9.82 ppm until manufacturers can get caught up.

The FDA urged drugmakers to check in with its drug shortages staff if their losartan tests reveal NMBA concentrations above 0.96 ppm—the current acceptable daily intake (ADI)—and said it will determine whether the lots can go out “on a case by case basis.” The ADI reflects the daily exposure that would result in a 1:100,000 cancer risk after 70 years.

Agency scientists evaluated the risk of exposure to NMBA at levels up to 9.82 ppm and found that it presents no meaningful difference in cancer risk over six-months when compared to a lifetime of exposure to NMBA at 0.96 ppm.