Carbamate
Definition
Carbamic-acid ester insecticides (carbaryl, carbofuran, propoxur, aldicarb). Reversibly inhibit acetylcholinesterase by carbamylating the active-site serine; spontaneous decarbamylation makes oximes unnecessary and sometimes harmful.
- Class
- Carbamic-acid ester insecticides
- Examples
- Carbaryl, carbofuran, propoxur, aldicarb
- Mechanism
- Reversible carbamylation of acetylcholinesterase active-site serine
- Treatment note
- Spontaneous decarbamylation makes oximes unnecessary, sometimes harmful
Common questions
Why is carbamate poisoning treated differently from organophosphate poisoning?+
Carbamate inhibition of acetylcholinesterase reverses on its own within hours, so the enzyme-reactivating oxime drugs used for organophosphate poisoning are usually unnecessary and can, in some carbamate cases, worsen toxicity rather than help.
How can toxicology distinguish carbamate from organophosphate exposure post-mortem?+
Because carbamylated enzyme spontaneously reactivates, cholinesterase inhibition measured at autopsy may already be resolving, while parent carbamate compounds and their metabolites, rather than the enzyme adduct itself, are the more reliable analytical target for confirming exposure.
Why are carbamates common in wildlife poisoning cases specifically?+
Their fast onset, high potency at small doses, and off-label availability in agricultural settings make them a frequent choice for deliberately poisoning predators or scavengers, distinct from their legitimate registered use as crop insecticides.
Related terms
- AChE / BChE
- Acetylcholinesterase (RBC membrane bound, true cholinesterase) and butyrylcholinesterase (plasma, pseudo-cholinesterase). Both depressed in OP and carbamate exposure; plasma BChE falls first and...
- Aluminium Phosphide (AlP)
- Solid grain-fumigant rodenticide sold as Celphos, Quickphos, Sulfas tablets. On contact with moisture or stomach acid, releases phosphine (PH3) gas, which blocks...
- Ellman Method
- Standard spectrophotometric cholinesterase assay. Acetylthiocholine substrate plus 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) yields a yellow 5-thio-2-nitrobenzoate anion read at 412 nm. The rate of...
- Organochlorine (OC)
- Chlorinated hydrocarbon insecticides (DDT, BHC/lindane, endosulfan, dicofol, aldrin, dieldrin). Highly lipophilic, neurotoxic via voltage-gated sodium channel disruption, and persistent in fat and...
- Organophosphate (OP)
- A class of insecticides (monocrotophos, chlorpyrifos, methyl parathion, dichlorvos, phorate) that inhibit acetylcholinesterase, producing the cholinergic toxidrome. The dominant suicidal poison in...
- Pyrethroid
- Synthetic analogues of natural pyrethrins (deltamethrin, cypermethrin, permethrin, fenvalerate). Act on voltage-gated sodium channels like OC but break down quickly in mammals,...
- QuEChERS
- Quick, Easy, Cheap, Effective, Rugged and Safe sample-prep protocol for pesticide residues. Acetonitrile extraction, MgSO4 + NaCl partition, dispersive SPE clean-up with...