Doses - CEPHAPIRIN SODIUM, CEPHAPIRIN BENZATHINE
Dogs: 
For susceptible infections: a) 10 - 30 mg/kg IV or IM q6-8h (Vaden and Papich 1995)
b) 10 - 30 mg/kg IV, IM, SQ q8h (Riviere 1989)
c) 11 - 33 mg/kg IV q8h; 22 - 33 mg/kg IM or SQ q8h (Aronson and Aucoin 1989)
Cats: 
For susceptible infections: a) 11 - 33 mg/kg IV q8h; 22 - 33 mg/kg IM or SQ q8h (Aronson and Aucoin 1989)
b) 10 - 30 mg/kg IV, IM, SQ q8h (Riviere 1989)
c) 10 - 30 mg/kg IV or IM q6-8h (Vaden and Papich 1995)
Cattle: 
For mastitis: a) Lactating cow (Cefa-Lak®): After milking out udder, clean and dry teat area. Swab teattip with alcohol wipe and allow to dry. Insert tip of syringe into teat canal; push plungerto instill entire contents. Massage quarter and do not milk out for 12 hours. May repeatdose q12h. (Label directions; Cefa-Lak®¯Fort Dodge)
b) Dry Cow (Cefa-Dri®): Same basic directions as above, but should be done at the timeof drying off and not later than 30 days prior to calving. (Label directions; Cefa-Dri®¯Fort Dodge)
Horses: 
For susceptible infections: a) 20 mg/kg IM q8h or q12h if administered with probenecid (50 mg/kg intragastrically).(Juzwiak et al. 1989)
b) Foals: 20 - 30 mg/kg IV q6h (Caprile and Short 1987)
c) 20 mg/kg IM q8h (Brumbaugh 1987)
Dosage Forms/Preparations/FDA Approval Status/Withholding Times - Veterinary-Approved Products:
Cephapirin Sodium Mastitis Tube; 200 mg cephapirin per 10 ml tube; Cefa-Lak® (Fort Dodge);(OTC) Approved for use in lactating dairy cattle. Milk withdrawal = 96 hours; Slaughterwithdrawal = 4 days.
Cephapirin Benzathine Mastitis Tube; 300 mg cephapirin per 10 ml tube; Cefa-Dri® (Fort
Dodge); (OTC) Approved for use in dry dairy cattle. Milk withdrawal = 72 hours after calvingand must not be administered within 30 days of calving; Slaughter withdrawal = 42 days.