Amoxicillin/Clavulanate Potassium
Amoxicillin trihydrate and Clavulanate potassium
Also known as: Clavamox · Augmentin · Amoclan · amoxycillin · p-hydroxyampicillin · BRL 2333 · clavulanic acid · BRL-14151K · kalii clavulanas
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Audited v13 dosing evidence
Structured calculator evidenceSporadic bacterial cystitis (extra-label)
- q8-12h
NA
Governing clinical context (3)
- NOTE: All dosages listed are for combined quantities of both drugs (unless otherwise noted).
- ■ This medicine can be given with or without food, but gastrointestinal side effects might be prevented if this medicine is given with food.
- Clavulanate products should be stored at temperatures below 25°C (77°F), and some tablet formulations specify storage at 20°C to 25°C (68°F-77°F). Potassium clavulanate is very susceptible to moisture and should be protected from excessive humidity.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Amoxicillin/Clavulanate (commonly known by the veterinary trade name Clavamox®) is a highly effective, broad-spectrum potentiated aminopenicillin antibiotic.
- Broadened Spectrum: The addition of clavulanic acid, a beta-lactamase inhibitor, protects amoxicillin from enzymatic degradation, significantly expanding its spectrum to include many beta-lactamase-producing bacteria (e.g., Staphylococcus spp., E. coli).
- Clinical Utility: It is FDA-approved for use in dogs and cats for urinary tract infections (UTIs), skin and soft tissue infections, and periodontal disease.
- Empiric Choice: It is considered an excellent first-line empiric choice for bacterial cystitis in female dogs and, when combined with a fluoroquinolone, for hepatobiliary infections.
- Limitations: It is generally not effective against Pseudomonas aeruginosa or Enterobacter species, which often produce type I cephalosporinases that clavulanic acid cannot inhibit.
Mechanism of action
Amoxicillin is a time-dependent, bactericidal antibiotic that binds to Penicillin-Binding Proteins (PBPs) → inhibits bacterial cell wall peptidoglycan cross-linking → compromises cell wall integrity → cell lysis and death.
Clavulanic acid acts as a "suicide inhibitor" by competitively and irreversibly binding to beta-lactamase enzymes (types II, III, IV, V, and staphylococcal penicillinases) → prevents the enzymatic destruction of amoxicillin → restores and expands the antimicrobial spectrum against resistant organisms.
Note: There is little synergistic activity against organisms already susceptible to amoxicillin alone.
Safety & warnings
Contraindications
- Patients with a history of hypersensitivity to penicillins
- Small hindgut fermenters (rabbits, guinea pigs, chinchillas, hamsters) due to risk of fatal clostridial enterotoxemia
- Oral administration in patients with septicemia, shock, or grave illness (due to delayed/diminished GI absorption)
Adverse effects
- Gastrointestinal upset (anorexia, vomiting, diarrhea)
- Hypersensitivity reactions (rashes, fever, eosinophilia, anaphylaxis)
- Antibiotic-associated diarrhea and superinfections (due to altered gut flora)
- Neurotoxicity (e.g., ataxia in dogs) at very high doses or prolonged use
- Elevated liver enzymes (rare)
- Tachypnea, dyspnea, edema, and tachycardia (rarely reported in dogs)
Precautions
WARNING FOR EXOTIC PETS: Do not administer penicillins to rabbits, guinea pigs, chinchillas, or hamsters, as severe enteritis and fatal clostridial enterotoxemia may occur.
- Cross-Reactivity: Use cautiously in patients with documented hypersensitivity to other beta-lactam antibiotics (e.g., cephalosporins, carbapenems).
- Critically Ill Patients: Avoid oral administration in patients in shock or with septicemia due to unreliable gastrointestinal absorption.
- Laboratory Interference: May cause false-positive urine glucose determinations when using cupric sulfate solutions (e.g., Clinitest®).
Drug interactions
Theoretical in vitro antagonism; clinical importance is currently in doubt but historically not recommended to combine.
Amoxicillin may decrease the renal excretion of methotrexate, causing increased levels and potential toxic effects.
Competitively blocks the tubular secretion of most penicillins, thereby increasing serum levels and serum half-lives.
In vitro inactivation can occur if mixed together; serum concentrations of aminoglycosides may be falsely decreased if stored prior to analysis.
Monitoring
- Clinical efficacy (resolution of infection signs)
- Adverse gastrointestinal signs (vomiting, diarrhea, anorexia)
Pharmacokinetics
Half-life
Absorption
Clavulanate potassium is relatively stable in the presence of gastric acid and is readily absorbed. Peak levels occur about 1 hour after dosing.
Distribution
Clavulanic acid has an apparent volume of distribution of 0.32 L/kg in dogs. Distributes (with amoxicillin) into lungs, pleural fluid, and peritoneal fluid. Low concentrations in saliva, sputum, and uninflamed CSF. Readily crosses the placenta and is found in milk in low concentrations. 13% bound to proteins in dog serum.
Metabolism
Clavulanic acid is extensively metabolized in the dog primarily to 1-amino-4-hydroxybutan-2-one.
Elimination
Excreted unchanged in the urine via glomerular filtration. In dogs, 34-52% is excreted in urine, 25-27% in feces, and 16-33% into respired air.
Overdose
Acute oral penicillin overdoses are unlikely to cause significant problems other than gastrointestinal distress (vomiting, diarrhea, anorexia).
In humans, very high dosages of parenteral penicillins, especially in patients with underlying renal disease, have induced Central Nervous System (CNS) effects. Treatment of oral overdose should be supportive and symptomatic.
Available products
Formulations
- Oral tablets
- Chewable tablets
- Powder for oral suspension
Veterinary
- Oral Tablets (4:1 ratio): 62.5 mg (50 mg amoxicillin/12.5 mg clavulanic acid), 125 mg, 250 mg, 375 mg (Clavamox Tablets®)
- Powder for Oral Suspension: 50 mg amoxicillin/12.5 mg clavulanic acid per mL in 15 mL dropper bottles (Clavamox Drops®)
Human-labeled
- Tablets: 250 mg/125 mg, 500 mg/125 mg, 875 mg/125 mg (Augmentin®)
- Chewable Tablets: 125 mg/31.25 mg, 200 mg/28.5 mg, 250 mg/62.5 mg, 400 mg/57 mg (Augmentin®)
- Powder for Oral Suspension: Various strengths including 125 mg/31.25 mg per 5 mL, up to 600 mg/42.9 mg per 5 mL (Augmentin®, Amoclan®)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store clavulanate products at temperatures less than 24°C (75°F) in tight containers, protected from excessive humidity. After reconstitution, veterinary oral suspensions are stable for 10 days when refrigerated (discard unused portions after 10 days). If kept at room temperature, suspensions are stable for only 48 hours.
Client information
- Administration: You can give this medication with or without food. However, if your pet experiences stomach upset (vomiting or loss of appetite), giving the dose with a small meal or treat can help.
- Storage of Liquid: If you are using the oral liquid suspension, it is best kept in the refrigerator. Discard any unused liquid after 10 days, as it loses its effectiveness.
- Completion of Therapy: Always finish the entire prescription as directed by your veterinarian, even if your pet seems completely better. Stopping early can lead to resistant infections.
- Side Effects: Mild diarrhea or vomiting can occur. Contact your veterinarian if these signs become severe or if your pet stops eating.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.