Related Experiment Video

Updated: Jun 12, 2026

Ookluc: A Plasmodium berghei Line for Identifying Transmission-blocking Compounds
07:14

Ookluc: A Plasmodium berghei Line for Identifying Transmission-blocking Compounds

Published on: July 11, 2025

Pharmacokinetics of obidoxime in patients poisoned with organophosphorus compounds

H Thiermann1, F Eyer, N Felgenhauer

  • 1Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937 Munich, Germany. HorstThiermann@bundeswehr.org

Toxicology Letters
|June 15, 2010
PubMed
Abstract

Insights

This study shows that a specific obidoxime regimen effectively achieves therapeutic plasma levels for organophosphorus poisoning treatment. The treatment was well-tolerated and suitable for mass casualty events.

Area of Science:

  • Pharmacology
  • Toxicology
  • Emergency Medicine

Background:

  • Organophosphorus (OP) compounds inhibit acetylcholinesterase (AChE), leading to poisoning.
  • Oximes are crucial for reactivating inhibited AChE, serving as a causal therapy for OP intoxication.
  • Optimal oxime therapy requires prompt administration of effective doses to maximize reactivation potential.

Purpose of the Study:

  • To assess the achievement of a target obidoxime plasma concentration (10-20 microM) in severely OP-poisoned patients.
  • To evaluate the efficacy and tolerability of a specific obidoxime regimen in achieving therapeutic levels.

Main Methods:

  • A cohort of 34 severely OP-poisoned patients received an obidoxime regimen (250 mg IV bolus, then 750 mg/24h) in the ICU.
  • Plasma obidoxime concentrations were monitored using High-Performance Liquid Chromatography (HPLC).
  • The regimen was maintained as long as AChE reactivation was possible.

Main Results:

  • The regimen resulted in a mean steady-state plasma obidoxime concentration of 14.5+/-7.3 microM, within the target range.
  • A total of 2269+/-1726 mg of obidoxime was infused over 65+/-55 hours.
  • Obidoxime exhibited biphasic elimination (t1/2(1)=2.2h, t1/2(2)=14h) and accumulated in tissues like cartilage, kidney, and liver.

Conclusions:

  • The proposed obidoxime regimen successfully achieved the targeted therapeutic plasma concentrations in OP-poisoned patients.
  • Obidoxime demonstrated biphasic elimination and was well-tolerated, indicating a favorable safety profile.
  • This regimen is recommended for adults, even in mass casualty scenarios involving OP poisoning.

More Related Videos

An Intestine/Liver Microphysiological System for Drug Pharmacokinetic and Toxicological Assessment08:59

An Intestine/Liver Microphysiological System for Drug Pharmacokinetic and Toxicological Assessment

Published on: December 3, 2020

Related Concept Videos

Anticholinesterase Agents: Poisoning and Treatment01:26

Anticholinesterase Agents: Poisoning and Treatment

Anticholinesterases, also known as cholinesterase inhibitors, work by blocking the breakdown of acetylcholine, leading to its accumulation in the synaptic cleft. This accumulation indirectly enhances both muscarinic and nicotinic actions. These agents are classified as reversible or irreversible based on their mechanism of action.     
Irreversible agents form a strong bond with the cholinesterase enzyme, making it inactive. The breakdown of the phosphorylated enzyme is slower than the...
Indirect-Acting Cholinergic Agonists: Pharmacokinetics01:22

Indirect-Acting Cholinergic Agonists: Pharmacokinetics

Indirect-acting cholinergic agonists, or anticholinesterases, enhance the body's cholinergic activity by inhibiting acetylcholine's breakdown. They are categorized as reversible or irreversible agents based on their mechanism of action. They are further classified into short-acting, intermediate-acting, and long-acting agents based on their duration of action.
Reversible agents containing quaternary amines, such as neostigmine and edrophonium, are not easily absorbed orally because they are...
Prevention of Further Absorption of Poison01:14

Prevention of Further Absorption of Poison

In cases of acute poisoning, the primary objective is to prevent further absorption of the toxic substance into the body. Immediate interventions using various decontamination techniques targeting the gastrointestinal (GI) tract can achieve this. Decontamination is crucial to prevent poison from entering the systemic circulation, which involves washing affected areas with water and mild soap and removing contaminated clothing. Once external decontamination is done, attention must be turned to...
Enhanced Elimination of Poison01:26

Enhanced Elimination of Poison

Poison can be effectively removed from the gastrointestinal (GI) tract through various decontamination procedures.
Antidotes serve a crucial role in counteracting the effects of poison by inhibiting enzymes responsible for producing harmful drug metabolites. In some cases, these toxic metabolites can be neutralized by endogenous cosubstrates, which are maintained at specific concentrations to prevent interaction with cellular macromolecules and subsequent cell death.
Renal excretion is the...
Pharmaceutical Poisoning: Treatment Strategies01:26

Pharmaceutical Poisoning: Treatment Strategies

Treatment strategies for poisoning are a critical aspect of emergency medicine, focusing on preventing the absorption of toxins and enhancing their elimination. When a poisoning incident occurs, the first response is to halt exposure and decontaminate the patient, particularly through gastrointestinal (GI) methods if the poison was ingested.Gastrointestinal Decontamination Techniques:Activated charcoal is the cornerstone of GI decontamination. It works through adsorption, binding the toxin to...
Direct-Acting Cholinergic Agonists: Pharmacokinetics01:31

Direct-Acting Cholinergic Agonists: Pharmacokinetics

Direct-acting cholinergic agonists, such as synthetic choline esters and naturally occurring alkaloids, exert their effects by enhancing the actions of acetylcholine and stimulating the parasympathetic nervous system. Synthetic choline esters share structural similarities with acetylcholine. For example, they have a positively charged quaternary ammonium or onium group, contributing to their hydrophilic characteristics. As a result, they are poorly absorbed in the body through oral...