Ampicilli

# Ampicilli ## Overview - **Classification**: Penicillin antibiotic, Beta-lactam - **Mechanism**: Inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis. ## Primary Indications 1. **Bacterial Infections**: Respiratory tract, urinary tract, GI, skin and soft tissue. 2. **Meningitis**: Bacterial meningitis caused by susceptible organisms (e.g., _Listeria monocytogenes_). 3. **Endocarditis Prophylaxis/Treatment**: For susceptible enterococcal infections. 4. **Neonatal Sepsis**: Empiric treatment often with an aminoglycoside. ## Adult Dosing ### Standard Dosing **General Bacterial Infections (Moderate)** - **Dose**: **250 mg - 1 g** - **Frequency**: Every **4-6 hours** - **Route**: Oral (PO), Intravenous (IV), Intramuscular (IM) - **Maximum Dose**: **12 g/day** **Severe Infections / Bacterial Meningitis** - **Dose**: **1 - 2 g** - **Frequency**: Every **4-6 hours** - **Route**: Intravenous (IV) - **Maximum Dose**: **12 g/day** ### Dose Adjustments - **Renal Impairment**: Requires significant adjustment. - **CrCl 10-50 mL/min**: Administer standard dose every **6-12 hours**. - **CrCl <10 mL/min**: Administer standard dose every **12-24 hours**. - **Hemodialysis**: Administer after dialysis. - **Hepatic Impairment**: No specific dose adjustment generally needed. - **Elderly Patients**: Adjust dose based on renal function; monitor for adverse effects. ## Pediatric Dosing ### Neonates (0-28 days) **General Infections / Sepsis** - **Postnatal Age (PNA) <7 days, Gestational Age (GA) <30 weeks**: - **Dose**: **50 mg/kg/dose** - **Frequency**: Every **12 hours** - **PNA <7 days, GA 30-36 weeks**: - **Dose**: **50 mg/kg/dose** - **Frequency**: Every **8 hours** - **PNA <7 days, GA >37 weeks**: - **Dose**: **50 mg/kg/dose** - **Frequency**: Every **6 hours** - **PNA ≥7 days, GA <30 weeks**: - **Dose**: **50 mg/kg/dose** - **Frequency**: Every **8 hours** - **PNA ≥7 days, GA ≥30 weeks**: - **Dose**: **50 mg/kg/dose** - **Frequency**: Every **6 hours** - **Maximum**: Not typically defined by a single dose, but total daily dose should not exceed **300 mg/kg/day**. - **Route**: IV/IM - **Special Notes**: For meningitis, consider higher doses (e.g., **75-100 mg/kg/dose**) and closer intervals, often used with gentamicin. ### Infants (1-12 months) **General Infections** - **Dose**: **100-200 mg/kg/day** - **Frequency**: Divided every **6 hours** - **Maximum**: **12 g/day** - **Route**: IV/IM/PO **Meningitis** - **Dose**: **200-400 mg/kg/day** - **Frequency**: Divided every **4-6 hours** - **Maximum**: **12 g/day** - **Route**: IV/IM ### Children (1-12 years) **General Infections** - **Dose**: **100-200 mg/kg/day** - **Frequency**: Divided every **6 hours** - **Maximum**: **12 g/day** - **Route**: IV/IM/PO **Meningitis** - **Dose**: **200-400 mg/kg/day** - **Frequency**: Divided every **4-6 hours** - **Maximum**: **12 g/day** - **Route**: IV/IM ### Adolescents (13-18 years) - **Dose**: Treat with adult dosing regimens. - **Maximum**: **12 g/day** - **Route**: IV/IM/PO ## Safety Information ### Contraindications - **Absolute**: History of severe hypersensitivity reaction to penicillin or other beta-lactams. - **Absolute**: History of ampicillin-associated cholestatic jaundice/hepatic dysfunction. - **Relative**: Mononucleosis (increased risk of rash). ### Common Adverse Effects - **Common (1-10%)**: Diarrhea, rash (maculopapular), nausea, vomiting, urticaria. - **Serious but Rare**: Anaphylaxis, Stevens-Johnson syndrome, C. difficile-associated diarrhea, seizures (especially with high doses/renal impairment), hemolytic anemia, agranulocytosis. ### Key Drug Interactions - **Allopurinol**: Increased incidence of skin rash. - **Oral Contraceptives**: May reduce efficacy of oral contraceptives; advise backup method. - **Warfarin**: May increase INR; monitor closely, adjust warfarin dose. - **Methotrexate**: Reduced renal clearance of methotrexate; increased methotrexate toxicity. - **Probenecid**: Increases and prolongs ampicillin serum levels; useful for some infections. ## Monitoring & Follow-up - **Before Treatment**: Assess allergies, renal function (SCr, CrCl). - **During Treatment**: - Monitor for signs of allergic reaction (rash, dyspnea) especially with first dose. - Monitor for diarrhea (C. diff). - Monitor renal function in patients with impairment or prolonged high-dose therapy. - Monitor CBC for prolonged therapy. - Clinical response to therapy (e.g., fever resolution, symptom improvement). - **Clinical Signs**: Watch for skin rash, itching, swelling (especially face/throat), severe diarrhea. ## Clinical Pearls - 💡 **Administer on empty stomach (oral)**: Improves absorption of oral ampicillin, though IV is preferred for serious infections. - 💡 **Rash with Mononucleosis**: Almost all patients with infectious mononucleosis develop a rash if given ampicillin (or amoxicillin); avoid use. - 💡 **Complete Full Course**: Emphasize completing the entire prescribed course to prevent resistance, even if feeling better. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.