Monday, September 16, 2013

Sarin Antidote Is Hit With Supply Problems in U.S

Manufacturing Flaw Has Some U.S. Public-Health Officials Concerned

A manufacturing problem at a Pfizer Inc. division caused a flaw in prefilled syringes that contain antidotes to sarin nerve gas—one of the agents unleashed in Syria last month—and some U.S. public-health officials are concerned about getting adequate supplies at home.

Pfizer and the government have put priority on getting replacement syringes to the military, but there have been shortfalls for ambulances and hospitals that keep doses for first responders in the U.S., said John Dreyzehner, preparedness chairman for the Association of State and Territorial Health Officials.

The U.S. government has stockpiles across the country of medicines to combat anthrax, radiation exposure and the diseases that can accompany disasters like hurricanes and toxic spills. Many state and city authorities also maintain emergency medicines.

Sarin used in the Syrian chemical-weapons attack in August killed nearly 1,500 people, according to the U.S. government. Terrorists haven't used sarin in U.S. attacks.

The Food and Drug Administration said it was notified by Pfizer's Meridian Medical Technologies unit in mid-March that a small number of auto-injectors containing two drugs used to treat nerve-gas victims—atropine and pralidoxime—didn't contain enough of one or both of the drugs. Pfizer said the problem occurred at a Meridian plant in the U.S., but it declined to specify the location.

"Pfizer takes this matter very seriously and is working expeditiously to rectify this," said Pfizer spokesman Christopher Loder. He said there is no specific delivery date for replacements and declined to say whether manufacturing has resumed.
The dual-drug injector sold commercially or to civilian government agencies is called DuoDote. A similar dual-drug injector is sold to the U.S. military.

In August—more than five months after the initial notification to the FDA—Meridian sent a letter to health-care professionals and emergency personnel about "potential under-dosing or failure to activate" in DuoDote. It said the flaws occurred in about seven out of 1,000 units.

The standard shelf life for DuoDote is four years, but in a Sept. 5 memo, the FDA extended the expiration date by one year, meaning older lots can still be used. The FDA hasn't recalled any of the injectors.

Dr. Dreyzehner, the preparedness official, is also the state of Tennessee's health commissioner. He said first-responder kits on ambulances had included DuoDote, which was quicker to pack and use than two separate syringes, but supplies have run short because expired lots were removed earlier.

"The challenge is because of those shortages, in Tennessee, we have had to remove the DuoDote injections because they had expired," said Dr. Dreyzehner, adding that this has happened at many emergency-medical-preparedness teams around the country. He said DuoDote hasn't been replaced for many months, although the individual drugs are available.

Rep. Andy Harris (R., Md.), a medical doctor who practiced at Johns Hopkins Hospital in Baltimore for 28 years, said he was concerned about the availability of injectors. "With the recent use of the chemical weapon sarin in Syria, the importance of having effective dosages of DuoDote available is of even greater importance," he wrote in a letter Thursday to Meridian.

Sarin, an odorless, colorless nerve gas inhaled or absorbed through the skin, can be fatal within minutes. It cripples the respiratory center of the central nervous system and paralyzes muscles around the lungs, which causes suffocation. Pralidoxime relieves muscle paralysis, and atropine relieves respiratory paralysis.

Pfizer said its replacement program for faulty autoinjectors has prioritized military needs. The military has no shortages now and had about 2.8 million units in March, said Pentagon spokeswoman Jennifer Elzea.

Because nerve gas acts rapidly, the Centers for Disease Control and Prevention has distributed what it calls Chempacks to hundreds of places across the country. The packs contain separate injectors of pralidoxime and atropine as well as an anticonvulsant.

The government plans to eventually replace the separate injectors with DuoDote, according to the Department of Health and Human Services.

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