Ampicillin
Ampicillin is an aminopenicillin antibiotic used for susceptible bacterial infections, particularly when a parenteral beta-lactam is appropriate. Soluble sodium formulations and less soluble trihydrate preparations have different absorption and persistence profiles. Oral exposure is generally less favorable than with amoxicillin in small animals and is particularly poor in adult horses.
Ampicillin/sulbactam is a protected combination intended to overcome selected beta-lactamase-mediated resistance. The addition broadens activity against some organisms but does not establish reliable coverage of all enteric gram-negative bacteria or other resistant pathogens.
Group
Aminopenicillin antibacterial
Mechanism of Action
Ampicillin binds penicillin-binding proteins and blocks cross-linking of peptidoglycan in the bacterial cell wall. Actively growing susceptible bacteria lose wall integrity and are killed. Its effect depends on maintaining useful concentrations over time, making formulation and dosing interval relevant to antibacterial exposure.
Bacterial beta-lactamases can inactivate ampicillin by opening its beta-lactam ring. Sulbactam inhibits selected beta-lactamases and protects the ampicillin component, extending activity against some enzyme-producing organisms. Protection remains incomplete when resistance involves enzymes that are poorly inhibited, altered target proteins or restricted access to the target.
The sodium salt can produce rapid systemic exposure, whereas depot trihydrate products have slower absorption and lower peaks. These differences alter the concentration–time profile while the molecular antibacterial target remains the same.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection – soluble injection | 10 mg/kg | IV, IM, SC | Every 8 h | Do not use in: Severe penicillin hypersensitivity; Soluble ampicillin sodium, expressed as ampicillin. |
| Susceptible bacterial infection – oral treatment | 20 mg/kg | PO | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
| Susceptible bacterial infection – trihydrate injection | 10–50 mg/kg | IM, SC | Every 12–24 h | Do not use in: Severe penicillin hypersensitivity; Trihydrate depot suspension only; not for IV administration. Depot trihydrate only; do not substitute soluble sodium injection with this schedule. |
| Gram-positive infection – oral course | 10–20 mg/kg | PO | Every 12 h | Do not use in: Severe penicillin hypersensitivity |
| Gram-positive infection – injection course | 5 mg/kg | IM, SC | Every 12 h | Do not use in: Severe penicillin hypersensitivity |
| Gram-positive infection – injection course | 5 mg/kg | IV | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
| Gram-negative infection – oral course | 20–30 mg/kg | PO | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
| Gram-negative infection – injection course | 10 mg/kg | IM, SC | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
| Gram-negative infection – injection course | 10 mg/kg | IV | Every 6 h | Do not use in: Severe penicillin hypersensitivity |
| Urinary tract infection | 12.5 mg/kg | PO | Every 12 h | Up to 7 days; Do not use in: Severe penicillin hypersensitivity; 3–7 days. |
| Urinary tract infection | 6.6 mg/kg | IM, SC | Every 12 h | Up to 7 days; Do not use in: Severe penicillin hypersensitivity; 3–7 days; route-specific lower amount. |
| Soft-tissue bacterial infection | 10–20 mg/kg | PO, IM, SC | Every 8 h | Up to 7 days; Do not use in: Severe penicillin hypersensitivity |
| Pneumonia or systemic infection | 22 mg/kg | IV, SC, PO | Every 8 h | Up to 14 days; Do not use in: Severe penicillin hypersensitivity; 7–14 days; oral treatment only in a stable patient. |
| Meningitis or orthopedic infection | 22 mg/kg | IV, IM, SC, PO | Every 6–8 h | Do not use in: Severe penicillin hypersensitivity; Oral treatment only when reliable absorption is expected. |
| Sepsis or bacteremia | 20–40 mg/kg | IV, IM, SC | Every 6–8 h | Do not use in: Severe penicillin hypersensitivity |
| Neonatal sepsis | 50 mg/kg | IV, IO | Every 4–6 h | Do not use in: Severe penicillin hypersensitivity |
| Urinary infection – high oral alternative | 25 mg/kg | PO | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
| Acute leptospiremia | 22 mg/kg | IV | Every 6–8 h | Do not use in: Severe penicillin hypersensitivity; Until eating; then the described step-down is amoxicillin 22 mg/kg PO every 8 hours. This step-down alone does not establish elimination of renal carriage. |
| Ampicillin/sulbactam — Susceptible bacterial infection | 10 mg/kg | IV, IM | Every 8 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. Dose is ampicillin component; 2:1 combination supplies an additional 5 mg/kg sulbactam. |
| Ampicillin/sulbactam — Respiratory infection – combined-dose course | 50 mg/kg | IV | Every 8 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. Amount is the sum of ampicillin and sulbactam, in the 2:1 formulation. |
| Ampicillin/sulbactam — Serious bite wound | 30–50 mg/kg | IV | Every 8 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. Dose-component basis is not explicitly stated for this listing; do not equate it with the separate 50 mg/kg combined respiratory course. |
| Ampicillin/sulbactam — Intra-abdominal infection | 20 mg/kg | IV, IM | Every 6–8 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. Extrapolated regimen with limited animal evidence; component versus combined amount is not explicitly identified. |
| Ampicillin/sulbactam — Respiratory infection – 20 mg/kg alternative | 20 mg/kg | IV, IM | Every 6–8 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. Dose-component basis is not explicit; do not merge with the combined-dose course. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection – soluble injection | 10 mg/kg | IV, IM, SC | Every 8 h | Do not use in: Severe penicillin hypersensitivity; Soluble ampicillin sodium, expressed as ampicillin. |
| Susceptible bacterial infection – oral treatment | 20 mg/kg | PO | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
| Susceptible bacterial infection – trihydrate injection | 10–20 mg/kg | IM, SC | Every 12–24 h | Do not use in: Severe penicillin hypersensitivity; Trihydrate depot suspension only; not for IV administration. Depot trihydrate only; do not substitute soluble sodium injection with this schedule. |
| Gram-positive infection – oral course | 10–20 mg/kg | PO | Every 12 h | Do not use in: Severe penicillin hypersensitivity |
| Gram-positive infection – injection course | 5 mg/kg | IM, SC | Every 12 h | Do not use in: Severe penicillin hypersensitivity |
| Gram-positive infection – injection course | 5 mg/kg | IV | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
| Gram-negative infection – oral course | 20–30 mg/kg | PO | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
| Gram-negative infection – injection course | 10 mg/kg | IM, SC | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
| Gram-negative infection – injection course | 10 mg/kg | IV | Every 6 h | Do not use in: Severe penicillin hypersensitivity |
| Urinary tract infection | 20 mg/kg | PO | Every 8–12 h | Up to 14 days; Do not use in: Severe penicillin hypersensitivity; 7–14 days. |
| Soft-tissue bacterial infection | 20–40 mg/kg | PO | Every 8–12 h | Up to 14 days; Do not use in: Severe penicillin hypersensitivity |
| Systemic bacterial infection | 7–11 mg/kg | IV, IM, SC | Every 8–12 h | Do not use in: Severe penicillin hypersensitivity |
| Sepsis | 20–40 mg/kg | IV | Every 6–8 h | Do not use in: Severe penicillin hypersensitivity |
| Ampicillin/sulbactam — Susceptible bacterial infection | 10 mg/kg | IV, IM | Every 8 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. Dose is ampicillin component; 2:1 combination supplies an additional 5 mg/kg sulbactam. |
| Ampicillin/sulbactam — Respiratory infection – combined-dose course | 50 mg/kg | IV | Every 8 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. Amount is the sum of ampicillin and sulbactam, in the 2:1 formulation. |
| Ampicillin/sulbactam — Serious bite wound | 30–50 mg/kg | IV | Every 8 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. Dose-component basis is not explicitly stated for this listing; do not equate it with the separate 50 mg/kg combined respiratory course. |
| Ampicillin/sulbactam — Intra-abdominal infection | 20 mg/kg | IV, IM | Every 6–8 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. Extrapolated regimen with limited animal evidence; component versus combined amount is not explicitly identified. |
Horses
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection – soluble injection | 22 mg/kg | IM, IV | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Soluble ampicillin sodium, expressed as ampicillin. |
| Susceptible infection – sodium frequent alternative | 10–50 mg/kg | IV, IM | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
| Susceptible infection – trihydrate alternative | 5–20 mg/kg | IM | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Depot trihydrate only; do not substitute soluble sodium injection with this schedule. |
| Susceptible infection – sodium lower-dose alternative | 11–15 mg/kg | IM, IV | Every 6–8 h | Do not use in: Severe penicillin hypersensitivity |
| Foal infection – sodium course | 11 mg/kg | IM, IV | Every 6 h | Do not use in: Severe penicillin hypersensitivity; Foals. |
| Foal infection – sodium higher-dose alternative | 15–30 mg/kg | IV, IM | Every 6–8 h | Do not use in: Severe penicillin hypersensitivity; Foals. |
| Ampicillin/sulbactam — Susceptible bacterial infection – 11 mg/kg listing | 11 mg/kg | IM, IV | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. The large-animal listing does not state whether this amount is ampicillin alone or combined actives; retain separately until dose basis is clarified. |
| Ampicillin/sulbactam — Susceptible bacterial infection – 22 mg/kg listing | 22 mg/kg | IM, IV | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. The large-animal listing does not state whether this amount is ampicillin alone or combined actives; retain separately until dose basis is clarified. |
Cattle
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection – soluble injection | 22 mg/kg | IM, IV | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Soluble ampicillin sodium, expressed as ampicillin. |
| Susceptible bacterial infection – trihydrate injection | 11 mg/kg | IM | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Cattle and calves; depot trihydrate formulation. Depot trihydrate only; do not substitute soluble sodium injection with this schedule. |
| Respiratory infection – trihydrate SC | 22 mg/kg | SC | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Depot suspension; withdrawal cannot be inferred from lower-dose labeling. Depot trihydrate only; do not substitute soluble sodium injection with this schedule. |
| Respiratory infection – sodium SC | 22 mg/kg | SC | Every 12 h | Do not use in: Severe penicillin hypersensitivity |
| Respiratory infection – trihydrate daily alternative | 11 mg/kg | IM | Every 24 h | Do not use in: Severe penicillin hypersensitivity; Depot trihydrate only; do not substitute soluble sodium injection with this schedule. |
| Ampicillin/sulbactam — Susceptible bacterial infection – 11 mg/kg listing | 11 mg/kg | IM, IV | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. The large-animal listing does not state whether this amount is ampicillin alone or combined actives; retain separately until dose basis is clarified. |
| Ampicillin/sulbactam — Susceptible bacterial infection – 22 mg/kg listing | 22 mg/kg | IM, IV | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. The large-animal listing does not state whether this amount is ampicillin alone or combined actives; retain separately until dose basis is clarified. |
Sheep
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection – soluble injection | 22 mg/kg | IM, IV | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Soluble ampicillin sodium, expressed as ampicillin. |
| Ampicillin/sulbactam — Susceptible bacterial infection – 11 mg/kg listing | 11 mg/kg | IM, IV | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. The large-animal listing does not state whether this amount is ampicillin alone or combined actives; retain separately until dose basis is clarified. |
| Ampicillin/sulbactam — Susceptible bacterial infection – 22 mg/kg listing | 22 mg/kg | IM, IV | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. The large-animal listing does not state whether this amount is ampicillin alone or combined actives; retain separately until dose basis is clarified. |
Goats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection – soluble injection | 22 mg/kg | IM, IV | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Soluble ampicillin sodium, expressed as ampicillin. |
| Ampicillin/sulbactam — Susceptible bacterial infection – 11 mg/kg listing | 11 mg/kg | IM, IV | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. The large-animal listing does not state whether this amount is ampicillin alone or combined actives; retain separately until dose basis is clarified. |
| Ampicillin/sulbactam — Susceptible bacterial infection – 22 mg/kg listing | 22 mg/kg | IM, IV | Every 12 h | Do not use in: Severe penicillin hypersensitivity; Ampicillin/sulbactam: Combination-specific regimen; do not apply this amount to plain ampicillin. The large-animal listing does not state whether this amount is ampicillin alone or combined actives; retain separately until dose basis is clarified. |
Pigs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection – trihydrate injection | 15 mg/kg | IM | Every 24 h | Do not use in: Severe penicillin hypersensitivity; Depot trihydrate only; do not substitute soluble sodium injection with this schedule. |
| Susceptible infection – sodium injection | 6–8 mg/kg | SC, IM | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
Ferret
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection | 5–10 mg/kg | IV, IM, SC | Every 12 h | Do not use in: Severe penicillin hypersensitivity |
Gerbil
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection | 20–100 mg/kg | PO, SC, IM | Every 8–12 h | Do not use in: Severe penicillin hypersensitivity |
Mouse
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection | 20–100 mg/kg | PO, SC, IM | Every 8–12 h | Do not use in: Severe penicillin hypersensitivity |
Rat
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection | 20–100 mg/kg | PO, SC, IM | Every 8–12 h | Do not use in: Severe penicillin hypersensitivity |
Hedgehog
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection | 10 mg/kg | IM, PO | Every 24 h | Do not use in: Severe penicillin hypersensitivity |
Amazon parrot
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible infection – oral course | 150–200 mg/kg | PO | Every 8–12 h | Do not use in: Severe penicillin hypersensitivity; Oral absorption is poor. |
| Susceptible infection – trihydrate IM | 100 mg/kg | IM | Every 4 h | Do not use in: Severe penicillin hypersensitivity; Polyflex trihydrate formulation. Depot trihydrate only; do not substitute soluble sodium injection with this schedule. |
Bird
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible infection – IM course | 100 mg/kg | IM | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
Ratite
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible infection – oral or IV course | 11–15 mg/kg | PO, IV | Every 8 h | Do not use in: Severe penicillin hypersensitivity |
| Susceptible infection – IM course | 15–20 mg/kg | IM | Every 12 h | Do not use in: Severe penicillin hypersensitivity |
Reptile
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection | 3–6 mg/kg | PO, SC, IM | Every 12–24 h | Up to 14 days; Do not use in: Severe penicillin hypersensitivity; Often used with an aminoglycoside; single-agent usefulness is limited. |
Chelonian
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Susceptible bacterial infection | 50 mg/kg | IM | Every 12 h | Do not use in: Severe penicillin hypersensitivity |
Indications
- Ampicillin alone for susceptible skin, soft-tissue, urinary and respiratory infections, including pneumonia.
- Selected perioperative antibacterial treatment or prophylaxis according to procedure and contamination risk.
- Ampicillin/sulbactam for susceptible acute infections, including selected pneumonia and sepsis cases.
- Selected antibacterial prophylaxis with ampicillin/sulbactam in neutropenic patients at significant infection risk.
Contraindications
- Penicillin hypersensitivity requires caution.
- Rapid IV boluses can cause CNS excitation and seizures.
- Consider sodium exposure: approximately 3 mEq per gram of ampicillin sodium.
- Documented severe penicillin hypersensitivity; cross-reactivity with other beta-lactams is possible.
- Avoid oral systemic treatment during shock or severe sepsis because gastrointestinal absorption may fail.
- Rabbits, guinea pigs, chinchillas and hamsters are at risk of severe antibiotic-associated enterocolitis.
- Ampicillin/sulbactam: Penicillin hypersensitivity requires caution.
- Ampicillin/sulbactam: Documented severe penicillin hypersensitivity; cross-reactivity with other beta-lactams is possible.
- Ampicillin/sulbactam: Avoid oral systemic treatment during shock or severe sepsis because gastrointestinal absorption may fail.
- Ampicillin/sulbactam: Rabbits, guinea pigs, chinchillas and hamsters are at risk of severe antibiotic-associated enterocolitis.
Interactions
- Do not mix with other drugs in the vial.
- Probenecid can reduce renal tubular secretion and prolong exposure.
- Bacteriostatic-antibiotic antagonism is demonstrated in vitro, but its clinical significance is uncertain.
- Methotrexate elimination may decrease with aminopenicillins, increasing toxicity.
- Ampicillin/sulbactam: Do not mix with other drugs in the vial.
- Ampicillin/sulbactam: Probenecid can reduce renal tubular secretion and prolong exposure.
- Ampicillin/sulbactam: Bacteriostatic-antibiotic antagonism is demonstrated in vitro, but its clinical significance is uncertain.
- Ampicillin/sulbactam: Methotrexate elimination may decrease with aminopenicillins, increasing toxicity.
Adverse effects
- Allergic reactions including anaphylaxis.
- Diarrhea, especially with high oral doses.
- Rare severe allergy, cytopenias or neurotoxicity with very high or prolonged exposure.
- Altered intestinal flora can cause antibiotic-associated diarrhea or superinfection.
- Ampicillin/sulbactam: Hypersensitivity, including anaphylaxis.
- Ampicillin/sulbactam: Rare severe allergy, cytopenias or neurotoxicity with very high or prolonged exposure.
- Ampicillin/sulbactam: Altered intestinal flora can cause antibiotic-associated diarrhea or superinfection.
Toxicity
Rapid IV administration can cause convulsions.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Ampicillin 125 mg capsule | Capsule | 125 mg / capsule | PO |
| Ampicillin 250 mg capsule | Capsule | 250 mg / capsule | PO |
| Ampicillin 500 mg capsule | Capsule | 500 mg / capsule | PO |
| Ampicillin sodium reconstituted 250 mg ampicillin/mL Soluble injection expressed as ampicillin; use within 1 hour at this concentration. | Injection | 250 mg / mL | IM, IV, SC |
| Ampicillin 125 mg per 5 mL oral suspension | Oral Liquid | 125 mg / 5 mL | PO |
| Ampicillin 250 mg per 5 mL oral suspension | Oral Liquid | 250 mg / 5 mL | PO |
| Ampicillin/sulbactam reconstituted 45 mg/mL combined Ampicillin/sulbactam: 2:1 combination diluted to a combined 45 mg/mL; ampicillin-component concentration is 30 mg/mL. Use sterile-water or saline dilution conditions. | Injection | ampicillin 30 mg / mL + sulbactam 15 mg / mL | IV, IM |
Monitoring and Administration
Select the formulation before selecting a schedule: soluble sodium injection and trihydrate suspension are not interchangeable IV products.
At 250 mg/mL, reconstituted soluble injection should be used within 1 hour and administered IV slowly over 3 minutes or longer as appropriate. The described 1 g and 2 g vials use 3.5 mL and 6.8 mL sterile water for IM preparation to approximately 250 mg/mL. For IV use, the described diluent additions are 7.4 mL and 14.8 mL, with administration over 15 minutes.
At up to 30 mg/mL in saline or lactated Ringer’s, stability is 8 hours at room temperature. Refrigerated 30 mg/mL solution is stable 48 hours in sterile water or 24 hours in saline/Ringer’s. At 20 mg/mL, refrigerated stability is 72 hours in water or 48 hours in saline; 5% dextrose solutions remain stable only 1 hour.
Refrigerated oral suspension has 14-day stability. Trihydrate-injection storage periods differ by product labeling; use the exact preparation instructions and protect dry forms from moisture.
MIC criteria are ≤0.25 mcg/mL for susceptible listed isolates, including bovine and equine respiratory pathogens; uncomplicated canine lower urinary infection uses ≤8 mcg/mL and may also apply to cats.
Monitor response and gastrointestinal tolerance. Copper-reduction urine-glucose tests may be falsely positive; glucose-oxidase methods are unaffected. Beta-lactams can lower measured aminoglycoside concentrations in stored samples; freeze samples if analysis is delayed.
Equine intrauterine ampicillin is described at 1–3 g, often daily or every other day for 3–7 days, but evidence, dilution and infusion volume are limited; it is retained outside systemic calculation.
Avian feed/water alternatives: 250 mg capsule per 8 ounces drinking water for pet birds; 1.65 g/L for chickens; 250 mg/kg via feed for 5–10 days for a broad bird listing without a defined repeat interval. Poor absorption, rapid elimination and variable intake limit these mixture regimens.
Give oral ampicillin on an empty stomach, at least 1 hour before or 2 hours after food. Oral suspension is stable 14 days refrigerated or 7 days at room temperature. For Polyflex, refrigerate after reconstitution, avoid freezing and discard within 3 months of first puncture.
Polyflex reconstitution options supply 50, 100 or 250 mg ampicillin-equivalent per mL. These are depot trihydrate concentrations, not soluble sodium concentrations; preparation selection must preserve the specific formulation.
Ampicillin/sulbactam: Small-animal doses are expressed as the ampicillin component, not total powder weight. Oral amoxicillin/clavulanate is described as an alternative when an oral agent is needed.
Ampicillin/sulbactam: The 2:1 product is supplied in 1.5 g and 3 g vials. Concentrated preparations should be used within 1 hour; IV administration is slow, over at least 3 minutes. Lidocaine-containing IM diluent must never be used IV.
Ampicillin/sulbactam: At a described 45 mg/mL combined concentration in sterile water or 0.9% saline, stability is 8 hours at room temperature and 48 hours refrigerated; with lactated Ringer’s it is 8 hours at room temperature and 24 hours refrigerated.
Ampicillin/sulbactam: Human susceptibility breakpoints may overpredict veterinary susceptibility; clinical guidance uses the lower ampicillin criterion for animal isolates.
Ampicillin/sulbactam: Combination preparation conversion requires explicit dose-component and ratio support; do not treat the combined preparation as a single ingredient.
Ampicillin/sulbactam: A human paired ampicillin/sulbactam MIC criterion of ≤8/4 mcg/mL is discussed, but the lower veterinary ampicillin criterion of ≤0.25 mcg/mL is preferred for these animal isolates.
Ampicillin/sulbactam: Monitor response and gastrointestinal tolerance. Copper-reduction urine-glucose tests may be falsely positive; glucose-oxidase methods are unaffected. Beta-lactams can lower measured aminoglycoside concentrations in stored samples; freeze samples if analysis is delayed.
Ampicillin/sulbactam: For the specified IV dilution, 30 mg/mL combined (20 mg/mL ampicillin plus 10 mg/mL sulbactam) is stable 72 hours at 4°C. Further dilute the selected amount into 50–100 mL saline and administer over 15–30 minutes. For IM reconstitution, 1.5 g and 3 g vials take 3.2 mL and 6.4 mL diluent respectively and are used within 1 hour; lidocaine-containing diluent is for IM use only. Do not calculate final concentration from added volume without accounting for displacement.
Ampicillin/sulbactam regimens are listed separately within this monograph. Their stated ingredient or combined-dose basis and formulation ratio must be retained; they are not interchangeable with the plain antibiotic regimen.