Selected Antimicrobial Information – Companion Animal
Amoxicillin [Companion]
Restriction Status
Unrestricted
Dose
| Species | Usage | Dose |
|---|---|---|
| Cats | Label dose | 50mg/cat (11-22mg/kg) PO q24h for 5-7d (can be used q12h extra-label) |
| For soft tissue infections | 6-22mg/kg PO PO q8h for 5-7d (extra-label use) | |
| For sepsis | 22-30mg/kg IV, SQ, or PO q8h for 5-7d (extra-label use) | |
| Dogs | Label dose | 11mg/kg PO q12h |
| For uncomplicated UTI | 10-20mg/kg PO q12h for 5-7d (extra-label use) | |
| For soft tissue infections | 10-20mg/kg PO q8h for 7d (extra-label use) | |
| For sepsis or orthopedic infections | 22-30mg/kg IV, IM, SQ, or PO q6-8h (extra-label use) | |
| For Lyme Disease | 20mg/kg PO q8h for 30d (extra-label use) |
Brand Name(s)
Amoxil®, Amoxi-Tabs®, Amoxi-Drops®, Biomox®, etc.
Background
Amoxicillin is a bactericidal, time-dependent β-lactam antibiotic with improved activity against Gram-negative organisms when compared to penicillin, though with somewhat less activity against Gram-positive organisms. There is also some efficacy against anaerobes. Amoxicillin distributes widely through the plasma and can cross the blood-brain barrier when meninges are inflamed although it is uncertain if therapeutic concentrations are achieved. It does not penetrate abscesses or sites of tissue necrosis well. Excretion is primarily as unchanged drug in urine.
Except for uncomplicated (lower) urinary tract infections, amoxicillin should not be used to treat infections caused by Enterobacterales (e.g., E. coli, Klebsiella spp., Proteus spp., Enterobacter spp.) due to the inability of this drug to reach an effective inhibitory serum concentration for the required period when recommended dose regimen are used.
Acceptable Uses
- First line choice for empiric treatment of uncomplicated (lower) urinary tract infections.
- Treatment of susceptible nasopharyngeal, upper, or lower respiratory tract infections (except for infections caused by Enterobacterales and Staphylococcus spp.)
- Treatment of susceptible otitis media (except for infections caused by Enterobacterales and Staphylococcus spp.)
- Treatment of susceptible soft tissue infections (except for infections caused by Enterobacterales and Staphylococcus spp.)
- Treatment of Lyme Disease (borreliosis).
- Can be used as an oral alternative to ampicillin.
Unacceptable Uses
- First line or empirical treatment of suspected Staphylococcus spp. infections due to widespread resistance.
- Soft tissue infections (e.g., wounds, otitis, pneumonia, among others) caused by Enterobacterales and Staphylococcus spp.
Formulations Available within the OSU Pharmacy
- Amoxicillin 40mg/mL oral suspension
- Amoxi-Tabs 100mg tablets
- Amoxi-Tabs 150mg tablets
- Amoxi-Tabs 200mg tablets
- Amoxi-Tabs 400mg tablets
Notes
- Ampicillin is used to predict amoxicillin susceptibility on the culture/susceptibility report (due to similarities in composition and mechanisms of action).
