Ampicillin
Also known as: Polyflex, Principen, Amfipen, Ampicare
* **Administration:** Unless otherwise instructed by your veterinarian, give this medication orally on an **empty stomach** (at least 1 hour before feeding or 2 hours after) to ensure proper absorption. * **Storage:** Keep the oral liquid suspension in the **refrigerator** and discard any unused portion after 14 days. If kept at room temperature, discard after 7 days. * **Side Effects:** Mild stomach upset (vomiting, diarrhea, or decreased appetite) may occur. If these signs are severe or persist, contact your veterinarian. * **Allergic Reactions:** Watch for signs of an allergic reaction, such as facial swelling, hives, rash, or difficulty breathing. Seek immediate veterinary care if these occur. * **Completion of Therapy:** Always finish the entire prescription as directed, even if your pet seems to be feeling better, to prevent the development of resistant bacteria.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Gram-positive infections
- Gram-negative infections
- Susceptible UTI's
- Susceptible soft tissue infections
- Pneumonia, systemic
- Meningitis, orthopedic infections
- Susceptible sepsis, bacteremia
- Neonatal sepsis
- Sepsis
- Susceptible UTI's
- To eliminate the leptospiremic phase of leptospirosis
- Routine infections
- CNS or serious bacterial infections
- Susceptible infections (Amazon parrots)
How it is given
Possible side effects
- Gastrointestinal upset (anorexia, vomiting, diarrhea)
- Antibiotic-associated diarrhea and superinfections (alteration of gut flora)
- Hypersensitivity reactions (rashes, fever, eosinophilia, anaphylaxis)
- Neurotoxicity (ataxia, seizures) at very high doses or prolonged use
- Elevated liver enzymes (rare)
- Tachypnea, dyspnea, edema, and tachycardia (reported in dogs)
Cautions & contraindications
- Patients with a known hypersensitivity to penicillins
- Oral administration in patients with septicemia, shock, or grave illness (due to delayed/diminished GI absorption)
- Oral or parenteral use in small hindgut fermenters (rabbits, guinea pigs, chinchillas, hamsters) due to risk of fatal clostridial enterotoxemia
- > **Cross-Reactivity:** Use cautiously in patients with documented hypersensitivity to other beta-lactam antibiotics (e.g., cephalosporins, carbapenems), as cross-reactivity can occur. > **Species Warning:** Severe, potentially fatal enteritis and clostridial enterotoxemia can occur if administered to rabbits, guinea pigs, chinchillas, or hamsters. > **Laboratory Interference:** May cause false-positive urine glucose determinations when using cupric sulfate solutions (e.g., Clinitest). Glucose oxidase tests are unaffected.
Drug interactions
- Bacteriostatic Antimicrobials (e.g., chloramphenicol, macrolides, tetracyclines): Potential in vitro antagonism; clinical significance is debated but concurrent use is traditionally discouraged.
- Methotrexate: Ampicillin may decrease the renal excretion of methotrexate, leading to increased levels and potential toxicity.
- Probenecid: Competitively blocks the tubular secretion of penicillins, increasing serum levels and prolonging half-life.
- Aminoglycosides (e.g., gentamicin, amikacin): In vitro inactivation of aminoglycosides if mixed in the same syringe or fluid bag. May also occur in vivo in patients with severe renal failure.
- Tetracycline: Antagonism of bactericidal effect due to bacteriostatic action
- Erythromycin: Antagonism of bactericidal effect due to bacteriostatic action
- Chloramphenicol: Antagonism of bactericidal effect due to bacteriostatic action
- Aminoglycosides: In vitro inactivation if mixed in the same syringe; however, exhibits synergistic antimicrobial effects when used concurrently in vivo
Frequently asked questions
What is Ampicillin used for in pets?
* **Administration:** Unless otherwise instructed by your veterinarian, give this medication orally on an **empty stomach** (at least 1 hour before feeding or 2 hours after) to ensure proper absorption. * **Storage:** Keep the oral liquid suspension in the **refrigerator** and discard any unused portion after 14 days. If kept at room temperature, discard after 7 days. * **Side Effects:** Mild stomach upset (vomiting, diarrhea, or decreased appetite) may occur. If these signs are severe or persist, contact your veterinarian. * **Allergic Reactions:** Watch for signs of an allergic reaction, such as facial swelling, hives, rash, or difficulty breathing. Seek immediate veterinary care if these occur. * **Completion of Therapy:** Always finish the entire prescription as directed, even if your pet seems to be feeling better, to prevent the development of resistant bacteria.
Is Ampicillin safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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