Adult: PO Susceptible infections 0.25-0.5 g 6 hrly. Typhoid and paratyphoid fever 1-2 g 6 hrly. Duration: 2 wk (acute infections); 4-12 wk (carriers). Uncomplicated gonorrhoea W/ probenecid: 2 g as single dose. IV/IM: IV Intrapartum prophylaxis against group B streptococcal infections Initial, 2 g, then 1 g 4 hrly until delivery. Septicaemia 150-200 mg/kg/day. Start with IV admin for 3 days, then IM inj 3-4 hrly. Continue treatment for at least 48-72 hr after patient has become asymptomatic or when there is evidence of bacterial eradication. IV/IM Susceptible infections 250-500 mg 6 hrly. Meningitis 2-3 g 4-6 hrly, may start w/ IV admin, then continue w/ IM inj. Inj Supplement to systemic therapy For intrapleural/intraperitoneal/intra-articular admin: 500 mg/day.
May reduce the efficacy of OC. May alter INR while on warfarin and phenindione. May reduce the efficacy of oral typhoid vaccines. May reduce the excretion of methotrexate. Reduced excretion w/ probenecid and sulfinpyrazone, resulting to increased risk of toxicity. Allopurinol increases ampicillin-induced skin reactions. Reduced absorption w/ chloroquine. Bacteriostatic antibacterials (e.g. erythromycin, chloramphenicol, tetracycline) may interfere w/ the bactericidal action of ampicillin.
Renal failure; patients with lymphatic leukaemia or HIV infections; pregnancy and lactation. Lactation: Excreted in breast milk, use caution
Ampicillin exerts bactericidal action on both gm+ve and gm-ve organisms. Its spectrum includes gm+ve organisms eg, S pneumoniae and other Streptococci, L monocytogenes and gm-ve bacteria eg, M catarrhalis, N gonorrhoea, N meningitidis, E coli, P mirabilis, Salmonella, Shigella, and H influenzae. Ampicillin exerts its action by inhibiting the synthesis of bacterial cell wall.
Susceptible infections Child: PO: 50–100 mg/kg/day divided q6hr if <20 >20 kg 1–2 g/day divided q6hr IV/IM: Child: 50–200 mg/kg/day q6h 300–400 mg/kg/day endocarditis/meningitis q4–6h
Should be taken on an empty stomach. Take on an empty stomach 1 hr before or 2 hr after meals. Reconstitution: IM: Add 1.5 mL water for inj to 500 mg vial contents. IV: Dissolve 500 mg in 10 mL water for inj.
Bacterial infections, Endocarditis, Typhoid fever, Community-acquired pneumonia, Uncomplicated gonorrhea, Susceptible infections, Bacterial meningitis, Paratyphoid fever, Septicaemia, Intrapartum prophylaxis against group B streptococcal infections
Renal impairment: Patients undergoing haemodialysis should receive an additional dose after the session. CrCl (ml/min) <10 Dose reduction or increase in dose interval.
GI upset, nausea, vomiting, diarrhoea; blood dyscrasias; urticaria, exfoliative dermatitis, rash; fever, seizures; interstitial nephritis. Potentially Fatal: Anaphylactic shock; pseudomembranous colitis; neuromuscular hypersensitivity; electrolyte imbalance.
Hypersensitivity; infectious mononucleosis.