Toltrazuril is a triazinon derivative. It acts against coccidia of the genus Isospora and Eimeria. It is acting against all intracellular development stages of coccidia: merogony (asexual multiplication) and gamogony (sexual phase). All stages are destroyed, thus the mode of action is coccidiocidal.

Piglets:

After oral administration, toltrazuril is slowly absorbed with a bioavailability of 70%.

The maximum concentration (Cmax) of toltrazuril is of 8.9 mg/L and is obtained after around 24 h. The main metabolite is characterised as toltrazuril sulfone. The elimination of toltrazuril is slow with a terminal half-life elimination time around 76 hours. The major route of excretion is via the faeces.

Calves:

After oral administration toltrazuril is slowly absorbed.

The maximum concentration (Cmax) toltrazuril is of 36.3 mg/L and is obtained after around 36 h.

The main metabolite is characterised as toltrazuril sulfone. The elimination of toltrazuril is slow with a terminal half-life time of around 96.4 hours. The major route of excretion is via the faeces.

The metabolite of toltrazuril, toltrazuril sulfone (ponazuril) is a persistent (half-life > l year) and mobile compound and has adverse effects on both the growth and emergence of plants. Given the persistent properties of ponazuril repeated spreading of manure from treated animals may lead to an accumulation in the soil and consequently a risk to plants. The accumulation of ponazuril in soil together with its mobility also leads to a risk of leaching to groundwater. See Contraindications and Special precautions for use.