Monenesin is a carboxylic polyeter ionophore used as feed additive to control Coccidiosis in poultry. The first ionophore used in poultry industry. 



Fermentation product of Streptomyces cinnamonensis


Mode of Action:

Monovalent ionophoe, tend to combine more readily with sodium and potassium, causing the normal transport of these ions across surface membranes to fail.



100-110 ppm


Monensin has a relatively narrow therapeutic window, with episodes of severe and lethal intoxications reported in many animal species, e.g., cattle, poultry, sheep, horses, and dogs. One of the most striking findings of experimental or accidental monensin intoxication in animals is muscle necrosis and myoglobinuria. Target organs of monensin poisoning are skeletal and cardiac muscles. 

Monensin may produce poor feathering when feeding diets with low energy and low sulphur-containing amino acids; tiamulin interfers with metabolism of monensin in chickens.At recommended doses MON may be toxic to guinea fowl and other avian species; horses are very sensitive to MON (LD 50%: horse 2-3 mg/kg b.w., cattle 25 mg/kg; chickens 200 mg/kg); Monensin will cause deaths in equines thet ingest feed containing it.

Toxicity of monensin is due primarily to its ability to increase intracellular sodium concentration. Monensin is a Na+-selective carboxylic ionophore which forms lipid-soluble cation complexes that can traverse cell membranes rapidly.


Drug Interactions:

Simultaneous application of monensin and tiamulin may result in increased toxicity. Monensin showed adverse interactions with sulfa drugs and erythromycin..


Drug combinations:

Combinations of monensin and clopidol, monensin and lasalocid, and monensin and nicarbazin are said to be synergistic.



Oral bioavailability is 30% in broiler chickens.