Parasympathomimetic (Cholinergic)/Antibioterrorism Agents
Manufacturer: U.S. Army Medical Research and Materiel Command
Drug Approval Classification: Original New Drug Application (Approval Date: 02/05/03)
Dosing: The recommended pyridostigmine bromide dose for pretreatment of soman is one 30-mg tablet every 8 hours. Pyridostigmine bromide is to be taken several hours before exposure to soman.
Clinical Summary: The efficacy of pyridostigmine bromide as pretreatment for soman exposure is based on the use of animal data. The FDA issued guidance recently indicating that drug products may be approved for certain conditions when the drug cannot ethically or feasibly be tested in humans.
Soman exposure can cause loss of muscle control and death if the muscles required for breathing are paralyzed. Pyridostigmine bromide appears to work by preventing soman from blocking an enzyme that muscles need to work properly. Pyridostigmine bromide must be taken before exposure to soman. Pyridostigmine bromide alone will not protect against soman poisoning. However, nerve agent antidotes (atropine and pralidoxime) work better against soman if pyridostigmine bromide is taken before exposure to soman.
First approved by the FDA in 1955, pyridostigmine bromide has been deemed safe on the basis of its long-term use in the treatment of a neuromuscular disease called myasthenia gravis. The Department of the Army has submitted data from multiple controlled trials and uncontrolled clinical experience demonstrating pyridostigmine bromide is well tolerated at the doses intended for military use. The dose used for myasthenia gravis is higher than the dose used for pretreatment to protect against soman.
The FDA's approval of pyridostigmine requires the U.S. Army to conduct postmarketing studies to verify the drug's clinical benefit and safety when used as indicated.
The U.S. Army has also provided the FDA with details of an educational program for soldiers as part of the restricted approval of pyridostigmine bromide.
Contraindications to therapy include people who have a history of bowel or bladder obstruction, or sensitivity to certain medicines used during surgery (eg, physostigmine).
Adverse Effects: The most common side effects include stomach cramps, diarrhea, nausea, frequent urination, headaches, dizziness, shortness of breath, worsening of peptic ulcer, blurred vision, and watery eyes.
Medscape Pharmacists. 2003;4(1) © 2003 Medscape
Cite this: March 2003 - Medscape - Mar 20, 2003.