Ampicillin
Rx Only
GenericAmpicillin
Therapeutic ClassPenicillin Antibiotic
Common Dose250–500 mg every 6 hrs (oral)
Max / 24h12 g (IV/IM), 4 g (oral)
PregnancyCategory B
Indications ▼
Respiratory tract infections (pneumonia, bronchitis)
Urinary tract infections
Meningitis (bacterial)
Septicemia and endocarditis
Gastrointestinal infections (e.g., Salmonella, Shigella)
Skin and soft tissue infections
Mechanism & Pharmacokinetics ▼
Mechanism: Inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins, leading to cell lysis and death.
Pharmacokinetics: Rapidly absorbed orally; peak plasma 1–2 hr; widely distributed; crosses placenta; partially metabolized in liver; excreted mainly unchanged in urine; half-life ~1 hr.
Dosage & Administration ▼
| Patient Category | Recommended Dose | Max / 24h |
|---|---|---|
| Adults (oral) | 250–500 mg every 6 hours | 4 g |
| Adults (IV/IM) | 1–2 g every 6 hours | 12 g |
| Children | 50–100 mg/kg/day divided q6–8h | 12 g |
Administer IV slowly over 5–10 min; IM injection deep into large muscle. Oral forms can be taken with or without food.
Side Effects ▼
Common: Diarrhea, nausea, rash
Occasional: Vomiting, headache, hypersensitivity reactions
Rare: Anaphylaxis, Clostridium difficile-associated diarrhea, liver enzyme elevation
Contraindications ▼
Hypersensitivity to penicillins or cephalosporins
History of severe allergic reaction (anaphylaxis) to beta-lactams
Drug Interaction ▼
Probenecid: may decrease renal excretion and increase levels of ampicillin
Oral contraceptives: may reduce effectiveness (rare)
Other antibiotics: additive or antagonistic effects possible
Pregnancy & Lactation ▼
Category B: Safe in pregnancy when indicated
Excreted in breast milk; caution advised
Clinical / Research Summary ▼
Effectiveness: Broad-spectrum bactericidal activity against Gram-positive and some Gram-negative organisms.
Resistance Considerations: Monitor local resistance patterns; beta-lactamase producing organisms may require combination therapy.
Safety Profile: Generally well-tolerated; hypersensitivity reactions are the main concern.
Research Focus: Combination therapy with beta-lactamase inhibitors; optimization of dosing in renal impairment.
Storage & Handling ▼
Store at 20–25°C; protect from moisture and light
Keep out of reach of children
Patient Counseling Points ▼
How to take: Complete full course; do not skip doses
Missed dose: Take as soon as remembered; double dose not recommended
Possible side effects: Diarrhea, nausea, rash; report severe allergic reactions immediately
Monitor: Allergic symptoms; liver function if prolonged therapy
Drug interactions: Inform about other medications including probenecid and oral contraceptives
Lifestyle advice: Maintain hydration; report diarrhea lasting >2 days
Pregnancy and safety: Safe in pregnancy (Category B); use caution while breastfeeding
Brand Names (Bangladesh & Global) ▼
Ampicillin
Ampi
Amcill
Principen
Omnipen
Ampicil
Medical Disclaimer: This clinical summary is for informational purposes only. Always follow guidance from a qualified healthcare professional for dosage, interactions, and use.
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