Pen-G

Adult: Oral : Susceptible infections: 125-312 mg 4-6 hrly. IM/IV : Susceptible infections: 0.6-3.6 g/day in 4-6 divided doses. IV : Bacterial endocarditis: 7.2-12 g/day in divided doses. Intrapartum prophylaxis against group B Streptoccocal infection in neonates Initial: 3 g, followed by 1.5 g 4 hrly until delivery. Meningococcal meningitis; Pneumococcal meningitis: 2.4 g 4 hrly. Max: 18 g/day in meningococcal meningitis. Child: IV : Meningococcal meningitis, Pneumococcal meningitis: Newborn infants: 100 mg/kg daily in 2 divided doses; 1-4 wk: 150 mg/kg daily in 3 divided doses; >1 mth to 12 yr: 180-300 mg/kg daily in 4-6 divided doses. Parenteral : susceptible infections: Newborn infants: 50 mg/kg daily in 2 divided doses; 1-4 wk: 75 mg/kg daily in 3 divided doses; >1 mth to 12 yr: 100 mg/kg daily in divided doses, not exceeding 4 g/day.

Benzylpenicillin has a bactericidal action against gram positive bacteria, gram negative cocci, some other gram negative cross-linking stage of peptidoglycan production through binding and inactivation of transpeptidases on the inner surface of the bacterial cell membrane thus inhibiting bacterial cell wall synthesis. It is inhibited by penicillinase and other β-lactamases.

Nausea, vomiting, stomatitis, black or hairy tongue, rash, fever, serum-like sickness, convulsions, interstitial nephritis, haemolytic anaemia, granulocytopenia, agranulocytosis, leucopenia, thrombocytopenia

Hypersensitivity to benzylpenicillin and other penicillins.

Patient with history of allergy esp β-lactam allergy and/or asthma, seizure disorder. Diabetic patients. Renal impairment. Pregnancy and lactation.

May increase the risk of methotrexate toxicity. Increased plasma concentration with probenecid. Antagonism of bactericidal effect with bacteriostatic antibacterials (e.g. erythromycin, tetracyclines).