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

After oral administration in cattle toltrazuril is slowly absorbed. The maximal plasma concentration (Cmax = 36.6 mg/l) was observed between 24 and 48 hours (geometric mean 33.9 hours) following oral administration. The elimination of toltrazuril is slow with a terminal half-life time of approximately 2.5 days (64.2 hours). The main metabolite is characterised as toltrazuril sulfone. The major route of excretion is via the faeces.

After oral administration toltrazuril is slowly absorbed with a bioavailability of ≥70%. The main metabolite is characterised as toltrazuril sulfone. The elimination of toltrazuril is slow with a half-life elimination time around 3 days. The major route of excretion is via the faeces.

After oral administration toltrazuril is slowly absorbed in mammals. The main metabolite is characterised as toltrazuril sulfone. The maximal plasma concentration (Cmax = 62 mg/L) was observed 2 days following oral administration. The elimination of toltrazuril is slow with an elimination half-life time of approximately 9 days. The major route of excretion is via the faeces.

Cattle and Sheep
The metabolite of toltrazuril, toltrazuril sulfone (ponazuril) is a very persistent (half-life ca. 1 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 sections Contraindications and Special precautions for use.