Molecular Structure of Amprolium (CAS NO: 121-25-5):

Molecular Formula: C₁₄H₁₉ClN₄
Molecular Weight: 278.7805
IUPAC Name: 5-[(2-Methylpyridin-1-ium-1-yl)methyl]-2-propylpyrimidin-4-amine chloride
Synonyms of Amprolium (CAS NO: 121-25-5): 1-((4-Amino-2-propyl-5-pyrimidinyl)methyl)-2-methylpyridinium chloride ; 1-((4-Amino-2-propyl-5-pyrimidinyl)methyl)-2-methylpyridinium chloride monohydrochloride ; 1-((4-Amino-2-propyl-5-pyrimidinyl)methyl)-2-picolinium chloride ; 1-((4-Amino-2-propyl-5-pyrimidinyl)methyl)-2-picolinium chloride monohydrochloride ; Amprol, Veterinary ; Amprolio ; Amprolio [INN-Spanish] ; Amprolium [INN-Latin] ; Amprovine ; EINECS 204-458-4 ; 2-Picolinium, 1-((4-amino-2-propyl-5-pyrimidinyl)methyl)-, chloride ; Pyridinium, 1-((4-amino-2-propyl-5-pyrimidinyl)methyl)-2-methyl-, chloride
CAS NO: 121-25-5
Classification Code: Coccidiostat [for poultry] 
H bond acceptors: 4
H bond donors: 2
Freely Rotating Bonds: 4
Polar Surface Area: 32.9 Å² 
Storage temp.: 0-6°C
Stability: Stable. Incompatible with strong acids, strong bases, strong oxidizing agents.

 Amprolium (CAS NO.121-25-5) is used as a coccidiostat.

May cause Thiamine deficiency if given at high rates.

Mode of action: thiamine analog, competitively inhibits the active transport of thiamine.  The coccidia are 50 times as sensitive to this inhibition as is the host.
Pharmacokinetics: Freely soluble in water.
Dose:
In dogs and cats:  "extra label use":  300 to 400 mg/kg, SID for 5 days or 110 to 220 mg/kg SID for 7 to 12 days.
In chickens:   For prevention of coccidiosis:  36.3 - 113.5 g/ton in the feed or in the drinking water at 0.012%.  No withdrawal is needed.