Dosages of Penicillins
| Penicillin | Species | Dosage | Notes | 
|---|---|---|---|
| Sodium penicillin G | |||
| Cattle | 20,000 U/kg, IV or IM, q 6 h | ELDU | |
| Horses | 10,000–20,000 U/kg, IV or IM, q 6 h 20,000–25,000 U/kg, IV, q 6–8 h | Doses up to 44,000 U/kg have been used in refractory cases | |
| Potassium penicillin G | Turkeys | 1.5 million U/gal, PO in drinking water, q 24 h for 5 d | Meat withdrawal time, 1 d | 
| Horses | 20,000–25,000 U/kg, IV, q 6 h | Doses up to 44,000 U/kg have been used in refractory cases; injectable potassium penicillin G contain considerable potassium content (1.7 mEq/million U) and should be used with caution in horses with HYPP and other sensitive patients | |
| Procaine penicillin G | Cattle | 22,000–66,000 U/kg, IM or SC, q 24 h | Doses > 6,600 U/kg/d constitute ELDU | 
| Horses | 22,000–44,000 U/kg, IM, q 12–24 h | ||
| Swine | 15,000–40,000 U/kg, IM, q 24 h | Doses > 6,600 U/kg/d constitute ELDU | |
| Camelids | 22,000–44,000 U/kg, SC, q 12–24 h | ELDU | |
| Benzathine penicillin G | Beef cattle and calves | 12,000–40,000 U/kg, IM, q 48 h | Greatly extended withdrawal times for production animals should be anticipated; doses > 8,800 U/kg constitute ELDU | 
| Penicillin V | Dogs and cats | 15,000 U/kg or 8–10 mg/kg, PO, q 6–8 h | |
| Dicloxacillin sodium monohydrate | Dogs | 11–55 mg/kg, PO, q 8 h | |
| Cloxacillin sodium | Lactating dairy cattle | 200 mg/quarter, intramammary, q 12 h for 3 doses | Meat withdrawal time, 10 d; milk withdrawal time, 48 h | 
| Cloxacillin benzathine | Dry dairy cattle | 500 mg/quarter, intramammary, once at dry-off | Meat withdrawal time, 28 d | 
| Ampicillin sodium | Cats | 6.6–20 mg/kg, IV, IM, or SC, q 8–12 h | |
| Dogs | 10–40 mg/kg, IV, IM, or SC, q 6–12 h | ||
| Horses | 15–40 mg/kg, IM or IV, q 6 h | 20–40 mg/kg IV, q 6 h for foals | |
| Cattle | 4.4–11 mg/kg, IM, q 24 h; or 22 mg/kg, SC, q 12 h | ELDU | |
| Small ruminants and camelids | 10–20 mg/kg, IV, IM, or SC, q 8–12 h | ELDU | |
| Swine | 22 mg/kg, SC, q 12 h | ELDU | |
| Ampicillin trihydrate | Dogs, cats | 6.6 mg/kg, IM or SC, q 12 h | Injection is a suspension; should not be administered IV due to risk of anaphylaxis and death | 
| Cattle | 4.4–11 mg/kg, IM, q 24 h | ||
| Swine | 6.6 mg/kg, IM, q 12–24 h | ||
| Ampicillin-sulbactam | Dogs, cats | 10–30 mg/kg, IV, q 6–8 h; 3.75–8.3 mg/kg/h, IV as a constant-rate infusion | |
| Amoxicillin | Dogs, cats | 11–30 mg/kg, PO, SC, or IV, q 8–24 h | |
| Poultry | 100–125 mg/kg, PO, q 8–12 h | ELDU; antimicrobials administered via medicated feed to food-producing species require a VFD in the US | |
| Amoxicillin-clavulanate | Cats | 62.5 mg per cat, PO, q 12 h; 10–20 mg/kg, PO, q 8 h | |
| Dogs | 12.5–25 mg/kg, PO, q 8–12 h | ||
| Poultry | 125 mg/kg, PO, q 8–12 h | ELDU | |
| Ertapenem | Dogs | 30 mg/kg, SC, q 12 h | Reserved class, not for empiric treatment | 
| Cats | 30 mg/kg, IV or SC, q 8 h as needed | Reserved class, not for empiric treatment | |
| Imipenem cilastatin sodium | Dogs, cats | 5 mg/kg, IV, q 6–8 h | Reserved class, not for empiric treatment. May lower seizure threshold. | 
| Horses | 10–25 mg/kg, IV, q 6 h | Reserved class, not for empiric treatment | |
| Foals | 5 mg/kg, IV infused over 20 minutes, q 6–8 h | Reserved class, not for empiric treatment | |
| Meropenem | Dogs, cats | 8 mg/kg, SC, q 12 h; 12–24 mg/kg, IV, q 8 h | Reserved class, not for empiric treatment | 
| Ticarcillin-clavulanate | Dogs, cats | 25–50 mg/kg, IV or SC, q 8 h | Reserved class, not for empiric treatment | 
| Abbreviations: ELDU, extralabel drug use; HYPP, hyperkalemic periodic paralysis; VFD, veterinary feed directive. |