An online pharmacy has again stuck it to the FDA in a citizen petition after tipping off regulators to the existence of a potentially cancer-causing impurity in Zantac and other heartburn medicines. It is the same impurity that led to a global recall of blood pressure medicines.
Valisure says the FDA should recall Sanofi’s Zantac and all other ranitidine products “to protect the American public from further exposure to the potentially carcinogenic properties of Ranitidine,” according to the petition, which was filed last week before the FDA announced the problem and then was posted to a federal website Wednesday.
The New Haven, Connecticut-based operation tests all batches of the medicines it buys before selling them. It says that its tests “detected extremely high levels” of N-Nitrosodimethylamine (NDMA) in every lot of ranitidine that it tested. It tested batches made by different manufacturers and of different dose forms.
In addition to a complete recall, Valisure says the FDA needs to develop tests to detect the impurity and require manufacturers to use it.
So far, the FDA has simply alerted the public to the fact that NDMA has been found in ranitidine meds and is investigating to determine the source of the tainted ingredient and its risks at the levels in those drugs. So far, the FDA claims, the risk to consumers seems small.
Not so, says Valisure. Its tests found ranitidine can react with itself under standard analysis conditions to form NDMA “at levels well in excess of the permissible daily intake limit for this probable carcinogen,” just not high enough for acute toxicity. That is why it has slipped unnoticed through FDA required testing by manufacturers, Valisure asserts.
The pharmacy says its conclusions have been validated by academic studies, including a clinical trial by Stanford University that found NDMA levels well in excess of the FDA’s current daily acceptable intake limit.
The FDA has acknowledged receipt of the petition but in a standard letter says that does not mean it automatically accepts Valisure's findings. When it warned consumers last week of the potential risk, it didn’t suggest patients quit using their medicines, instead suggesting they check with their doctors. It said those who buy them over the counter might consider switching to an antacid that doesn’t contain ranitidine.
“Although NDMA may cause harm in large amounts, the levels the FDA is finding in ranitidine from preliminary tests barely exceed amounts you might expect to find in common foods,” the FDA said in its statement.
This is the second time in recent months Valisure has petitioned the FDA about the potentially cancer-causing impurities it has found in drugs approved by the agency. In June, it said it had discovered a connection between certain solvents that were approved for use in drug manufacturing and the existence of NDMA in certain heart meds. It suggested the FDA set standards for the use of the solvents.