Ampicillin
PRINCIPEN
What it isAminopenicillin; Listeria, enterococcal and susceptible Gram-negative infection.
Why this oneIt is the drug for Listeria meningitis, which cephalosporins do not cover.
What limits itBeta-lactamase producers escape it. Rash with concurrent EBV; frequent dosing.
FDA-approved for
- bacterial infections (1963)
- Listeria/Enterococcus infections (1963)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Genitourinary/GI tract infections | Adults & children >20 kg | 500 mg QID | ||
| Respiratory tract infections | Adults & children >20 kg | 250 mg QID | ||
| Gonorrhea | Adult | Single 3.5 g dose with 1 g probenecid | ||
| Genitourinary/GI tract infections | Children <=20 kg | 100 mg/kg/day divided QID | ||
| Respiratory tract infections | Children <=20 kg | 50 mg/kg/day divided TID-QID |
Renal Undefined
Hepatic Undefined
Instructions
- Administer at least 30 min before or 2 h after meals for maximal absorption
- Doses for children should not exceed doses recommended for adults
Contraindications
- Serious hypersensitivity (e.g., anaphylaxis, Stevens-Johnson syndrome) to ampicillin or other beta-lactams
- Infections caused by penicillinase-producing organisms
- Previous history of cholestatic jaundice/hepatic dysfunction associated with ampicillin
Cautions
- Hypersensitivity/anaphylactic reactions (more likely with prior penicillin allergy)
- Clostridioides difficile-associated diarrhea
Adverse reactions
- Hypersensitivity reactions (rash, urticaria)
- Diarrhea (incl. C. difficile-associated)
- Nausea, vomiting
- Glossitis, stomatitis
Pregnancy Animal reproduction studies revealed no evidence of impaired fertility or fetal harm; no adequate and well-controlled studies in pregnant women.
Lactation Undefined
NO BOXED WARNINGS
Principal riskHypersensitivity; beta-lactamase producers escape it
Cost, est. cash$10–$300/month
Generic entry1985
Classes and tags
Clinical profile
Legacy pregnancy categoryB
Defining liabilityAllergy, gastrointestinal effects and agent-specific renal, hepatic, hematologic or interaction risks.
Mechanism of action: Ampicillin ballicule
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Memory aids: mascots and interaction avatars
beta lactam ring