Ecothiopate binds irreversibly to cholinesterase. Because of the very slow rate at which echothiophate is hydrolyzed by cholinesterase, its effects can last a week or more. Adverse effects include muscle spasm and other systemic effects.
Shortage
Wyeth Pharmaceuticals stopped manufacturing ecothiopate iodide (phospholine iodide) in the US in 2003. After contacting the American Academy of Ophthalmology (AAO), Wyeth rescinded their decision and, according to AAO public relations representative Michelle Stephens, the AAO and Wyeth were in talks for about a year about manufacturing it.
In the meantime, a worldwide shortage of the drug has occurred.
Sources
Brenner, G. M. (2000). Pharmacology. Philadelphia, PA: W.B. Saunders Company. ISBN 0-7216-7757-6.
Canadian Pharmacists Association (2000). Compendium of Pharmaceuticals and Specialties (25th ed.). Toronto, ON: Webcom. ISBN 0-919115-76-4.
Rang, H. P. (2003). Pharmacology. Edinburgh: Churchill Livingstone, p. 146. ISBN 0-443-07145-4.