The Food and Drug Administration announced Tuesday it is blocking imports of the medicinal drug L-tryptophan, linked to a nationwide outbreak of a blood disorder that killed at least one person.
The action, which started in late November, follows the FDA's nationwide recall of non-prescription supplements of the amino acid used for sleeping disorders, premenstrual syndrome, depression and stress.
The FDA said it "imposed an automatic detention at U.S. ports on all L-tryptophan tablets, capsules, caplets and powders as well as on bulk shipments of L-tryptophan that are used in the production of these products."
The death of a 58-year-old New York state woman has been blamed on the blood disorder eosinophilia-myalgia syndrome, linked to use of the medicinal drug, the FDA said. Several deaths, including one in Minnesota, are under investigation, the agency said.
More than 700 people, including at least 122 in California, have taken ill after using L-tryptophan, according to statistics compiled by state health agencies and reported to the federal Centers for Disease Control.
The FDA noted "the detention and recall do not apply to products where L-tryptophan is a minor ingredient," such as foods with "naturally occurring levels of L-tryptophan."
Eosinophilia-myalgia syndrome is characterized by severe muscle and joint pain, swelling of the arms and legs, skin rash and fever.