Meropenem
Meropenem is a broad-spectrum beta-lactam reserved for confirmed infections resistant to suitable narrower-spectrum options.
Group
Carbapenem antibacterial
Mechanism of Action
Binds penicillin-binding proteins and inhibits bacterial cell-wall synthesis.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Resistant Enterobacterales infection | 10 mg/kg | IV, IM, SC | Every 8 h | Susceptibility-directed use. IM/SC use is extralabel. |
| Pseudomonas infection | 30 mg/kg | IV, IM, SC | Every 8 h | Susceptibility-directed use. IM/SC use is extralabel. |
| Continuous-infusion antibacterial therapy — Loading | 1 mg/kg | IV | Once | Follow with the separately listed infusion; solution stability and line compatibility require an appropriate hospital protocol. |
| Continuous-infusion antibacterial therapy — Maintenance | 1 mg/kg/hour | IV | Continuous | Use after the separately listed loading dose; prepare and replace infusion solutions within validated stability limits. |
| Bacteremia or sepsis | 24 mg/kg | IV | Every 24 h | A distinct historical formulary alternative; susceptibility and time-dependent exposure must guide selection. |
| Bacteremia or sepsis | 12 mg/kg | SC | Every 8 h | |
| Urinary tract infection | 12 mg/kg | SC | Every 12 h | |
| Central nervous system infection | 40 mg/kg | IV, SC | Every 8 h | Maximum 2000 mg/dose; Extrapolated from pediatric treatment; reserve for essential susceptibility-confirmed use. Maximum 2 g per administration. |
| Historical size-based systemic regimen | Reference only | IV | Historical totals every 8 hours: 125 mg for small dogs, 250 mg for medium dogs and 500 mg for dogs >100 lb; first two size definitions are absent. SC was also listed. A 12-hour interval was suggested with serum creatinine >4, but the unit is unstated; clarify before use. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible resistant bacterial infection | 10 mg/kg | IV, IM, SC | Every 12 h | IM/SC use is extralabel; choose therapy with culture results. |
| Bacteremia or sepsis | 24 mg/kg | IV | Every 24 h | A distinct historical formulary alternative; susceptibility and time-dependent exposure must guide selection. |
| Bacteremia or sepsis | 12 mg/kg | SC | Every 8 h | |
| Urinary tract infection | 12 mg/kg | SC | Every 12 h | |
| Central nervous system infection | 40 mg/kg | IV, SC | Every 8 h | Maximum 2000 mg/dose; Extrapolated from pediatric treatment; reserve for essential susceptibility-confirmed use. Maximum 2 g per administration. |
| Alternative systemic infection regimen | 8 mg/kg | IV, SC | Every 8 h | |
| Historical fixed systemic regimen | Reference only | SC | 125 mg total every 8 hours by IV or SC was listed for cats and small dogs, without individual weight qualification. The weight-based cat alternatives are more explicit; do not extrapolate across body sizes. |
Indications
- Resistant susceptible Enterobacterales infection
- Susceptible Pseudomonas infection
Contraindications
- Serious carbapenem hypersensitivity
- Prior anaphylaxis to a beta-lactam antibiotic
Interactions
- Do not mix in a syringe or vial with other antibiotics.
- Carbapenems can substantially lower valproate exposure.
- Probenecid can increase meropenem concentrations and elimination half-life.
Adverse effects
- Hypersensitivity
- Local injection-site hair changes
- Gastrointestinal disturbance
- Possible neurologic effects with excessive exposure
Toxicity
Discontinue for serious hypersensitivity or neurologic toxicity. Impaired renal clearance can increase exposure.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Meronic 500 mg injection vial Dry meropenem vial. Calculate vial equivalents only until this product’s final concentration is confirmed; no assumed injection volume. | Injection | 500 mg / vial | IV |
| Meronic 1000 mg injection vial Dry meropenem vial. Calculate vial equivalents only until this product’s final concentration is confirmed; no assumed injection volume. | Injection | 1000 mg / vial | IV |
| Meropenem compounded saline solution 20 mg/mL for SC use Sterile saline formulation described for veterinary SC administration. Product-specific compounding, light protection and validated storage are required; do not use Meronic vial size alone to infer this concentration. | Injection | 20 mg / mL | SC |
Monitoring and Administration
Confirm culture and susceptibility before selecting this reserve antimicrobial and reassess for de-escalation. Veterinary doses are supported primarily by pharmacokinetics.
Use validated product-specific diluent and storage times. Published formulation information describes 50 mg/mL reconstitution, room-temperature solution stability of 12 hours and refrigerated stability of 3 days; do not transfer these times across different manufacturers, diluents or concentrations without confirmation.
Inspect for particulates and marked amber/brown discoloration; slight yellowing alone need not indicate loss of potency.
Meropenem storage periods vary substantially by product and diluent. One manufacturer-based description limits reconstituted stock up to 50 mg/mL to 2 hours at room temperature or 12 hours refrigerated; selected 1–20 mg/mL saline/water syringe dilutions to 48 hours refrigerated. A reported 20 mg/mL saline SC preparation had a 96-hour refrigerated period and 6 hours after warming; these are formulation-specific and cannot replace the actual product instruction.
Prepare reserve-antibiotic therapy using renal function, organism MIC and infection site; do not automatically substitute the once-daily IV historical course for more frequent modern regimens.