Vetdrugs 2.0Carbenicillin is a semisynthetic carboxypenicillin with activity against susceptible gram-negative bacteria, including some Pseudomonas aeruginosa isolates. It belongs to the older antipseudomonal penicillins. Injectable carbenicillin has historically been used for systemic infections, whereas the oral indanyl ester was developed mainly for urinary tract treatment because it produces useful urinary concentrations.
Group
Antipseudomonal penicillin
Mechanism of Action
Carbenicillin binds bacterial penicillin-binding proteins, including transpeptidases responsible for cross-linking peptidoglycan. Blocking this final stage of cell-wall assembly weakens the wall of actively multiplying bacteria, allowing osmotic damage and bacterial death. Its antibacterial activity is time dependent. Its extended spectrum reflects entry into and binding within susceptible gram-negative organisms, including selected Pseudomonas strains.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infections | 40–50 mg/kg | IV, IM, SC | Every 6–8 h | Parenteral carbenicillin; an alternative high dose up to 100 mg/kg is separately described. |
| Higher-dose bacterial infection treatment | 100 mg/kg | IV, IM, SC | Every 6–8 h | |
| Urinary tract infection with oral prodrug | Reference only | PO | Carbenicillin indanyl sodium 10 mg/kg orally every 8 hours. This is a different chemical formulation; it is not automatically matched to carbenicillin injection strengths. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infections | 40–50 mg/kg | IV, IM, SC | Every 6–8 h | Parenteral carbenicillin; an alternative high dose up to 100 mg/kg is separately described. |
| Higher-dose bacterial infection treatment | 100 mg/kg | IV, IM, SC | Every 6–8 h | |
| Urinary tract infection with oral prodrug | Reference only | PO | Carbenicillin indanyl sodium 10 mg/kg orally every 8 hours. This is a different chemical formulation; it is not automatically matched to carbenicillin injection strengths. |
Indications
- Historically, parenteral treatment of susceptible gram-negative bacterial infections in dogs and cats, including Pseudomonas aeruginosa infections.
- Treatment of susceptible urinary tract infections in dogs and cats with the oral carbenicillin indanyl formulation.
Contraindications
- Penicillin hypersensitivity.
Interactions
- Do not mix with aminoglycosides or other medicines because of inactivation.
Adverse effects
- Allergy
- Platelet dysfunction and bleeding
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Carbenicillin 1000 mg vial Strength is per vial; no final mL concentration is implied. | Injection | 1000 mg / vial | IV, IM, SC |
| Carbenicillin 2000 mg vial Strength is per vial; no final mL concentration is implied. | Injection | 2000 mg / vial | IV, IM, SC |
| Carbenicillin 5000 mg vial Strength is per vial; no final mL concentration is implied. | Injection | 5000 mg / vial | IV, IM, SC |
| Carbenicillin 10000 mg vial Strength is per vial; no final mL concentration is implied. | Injection | 10000 mg / vial | IV, IM, SC |
| Carbenicillin 30000 mg vial Strength is per vial; no final mL concentration is implied. | Injection | 30000 mg / vial | IV, IM, SC |
| Geocillin carbenicillin indanyl sodium tablet Archived formulation: 500 mg indanyl sodium ester equivalent to 382 mg carbenicillin activity; not a claim of current availability. | Tablet | 382 mg / tablet | PO |
Monitoring and Administration
Use culture and susceptibility testing. Short elimination requires frequent parenteral dosing.
Carbenicillin indanyl sodium is an oral prodrug that achieves useful concentrations chiefly in urine; do not substitute it for systemic injectable therapy.
Reconstitute shortly before use; stability is greatest near pH 6.5.
Geocillin oral tablets contain 382 mg carbenicillin activity as 500 mg carbenicillin indanyl sodium. This verified strength equivalence does not establish whether an older veterinary 10 mg/kg prodrug regimen was expressed as prodrug or carbenicillin activity; that regimen therefore remains a reference record.
An archived product label establishes composition, not current availability or local authorization.