FDA approved Atnaa (atropine and pralidoxime chloride) for Organophosphorus Nerve Agent PoisoningFDA approved Atnaa, a Single-Shot Antidote for Nerve Agent Poisoning

FDA From the archive Source published January 17, 2002 Summary added October 16, 2026 DOI ↗ Editorial oversight: Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

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Key Takeaway

Note: Atnaa is for initial treatment of nerve agent poisoning; seek definitive care immediately.

The U.S. Food and Drug Administration has approved Atnaa (atropine and pralidoxime chloride) for the treatment of poisoning by susceptible organophosphorus nerve agents having anticholinesterase activity in adults. Atnaa combines atropine, a cholinergic muscarinic antagonist, and pralidoxime chloride, a cholinesterase reactivator, in a single-dose autoinjector designed for intramuscular administration.

The approval addresses a critical need for rapid, field-ready antidote administration in military or civilian settings where exposure to organophosphorus nerve agents is known or suspected. Atnaa is intended as an initial treatment as soon as symptoms appear, with definitive medical care sought immediately. The autoinjector is designed for self-administration for mild symptoms and buddy-administration for severe symptoms, allowing for prompt intervention when medical personnel are not immediately available.

Clinicians should recognize that Atnaa is not a substitute for definitive medical care. Close supervision of all treated service members is indicated for at least 48 to 72 hours. The label provides specific dosing instructions based on symptom severity and emphasizes the importance of administering the antidote as soon as possible after the appearance of symptoms for optimal reactivation of organophosphorus-inhibited cholinesterase.

＋ Clinical Details (Mechanism · Dosing · Trial Data · Warnings)

Mechanism of Action

Atnaa combines atropine, a cholinergic muscarinic antagonist, and pralidoxime chloride, a cholinesterase reactivator. Atropine blocks the effects of excess acetylcholine at muscarinic receptors, while pralidoxime chloride reactivates organophosphorus-inhibited cholinesterase.

Indication & Patient Population

Atnaa is indicated for the treatment of poisoning by susceptible organophosphorus nerve agents having anticholinesterase activity in adults. It is intended for use in service members at risk for organophosphorus nerve agent poisoning. Only administer Atnaa to service members experiencing symptoms of organophosphorus nerve agent poisoning in a situation where exposure is known or suspected.

Dosing & Administration

Three single-dose autoinjectors should be available for each service member at risk. For mild symptoms, self-administer one injection intramuscularly into the lateral thigh muscle or buttocks. Wait 10 to 15 minutes for effect. If symptoms are not relieved or if severe symptoms develop, a buddy should administer two additional injections intramuscularly in rapid succession. For severe symptoms, immediately buddy-administer three injections intramuscularly in rapid succession into the lateral thigh muscle or buttocks. Administer as soon as possible after symptoms appear. Close supervision for at least 48 to 72 hours is indicated. Inspect for particulate matter and discoloration prior to administration.

Key Clinical Trial Data

Trial data not available in label.

Warnings & Contraindications

Not reported in label.

Place in Therapy

Atnaa is intended as an initial treatment for organophosphorus nerve agent poisoning as soon as symptoms appear. Definitive medical care should be sought immediately. It is designed for self- or buddy-administration in a field setting after donning protective mask and hood at the first sign of a chemical attack. The autoinjector provides a fixed-dose combination of atropine and pralidoxime chloride for rapid intramuscular administration.

The FDA has approved a new drug called Atnaa. It treats poisoning from certain nerve agents, which are chemicals that can harm the body's nerves and muscles. Atnaa comes as a single-dose autoinjector, a device that delivers one shot into the muscle. It combines two medicines, atropine and pralidoxime chloride, that work together to counter the effects of these chemicals.

Atnaa is for adults who have been exposed to these nerve agents or are thought to have been exposed. It is meant to be used as soon as symptoms appear. The device is designed so people can give themselves a shot for mild symptoms, or a buddy can give the shot when symptoms are severe. This allows quick action when medical help is not nearby.

The approval matters because it offers a fast, ready-to-use option in military or emergency settings. Still, Atnaa is not a substitute for full medical care. Anyone treated should be watched closely by medical staff for at least 48 to 72 hours. If you have questions about this drug or your risk, talk to your doctor.

What this means for you:

Atnaa is a fast single-shot antidote for certain nerve agent poisoning, but it does not replace full medical care.

Study Details

Study typeFda approval

PublishedJan 2002

View Original Abstract ↓

1 INDICATIONS AND USAGE ATNAA is indicated for the treatment of poisoning by susceptible organophosphorus nerve agents having anticholinesterase activity in adults. ATNAA, a combination of atropine, a cholinergic muscarinic antagonist, and pralidoxime chloride, a cholinesterase reactivator, is indicated for the treatment of poisoning by susceptible organophosphorus nerve agents having anticholinesterase activity in adults. ( 1 )

FDA approved Atnaa (atropine and pralidoxime chloride) for Organophosphorus Nerve Agent PoisoningFDA approved Atnaa, a Single-Shot Antidote for Nerve Agent Poisoning

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FDA approved Atnaa (atropine and pralidoxime chloride) for Organophosphorus Nerve Agent PoisoningFDA approved Atnaa, a Single-Shot Antidote for Nerve Agent Poisoning

Study Details

Candidiasis prevalence of 13.46% and Cryptococcal meningitis of 3.15% among HIV-positive individuals

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Clinical research that matters. Delivered to your inbox.

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