Benzyl Penicillin

For use in the treatment of severe infections caused by penicillin G-susceptible microorganisms when rapid and high penicillin levels are required such as in the treatment of septicemia, meningitis, pericarditis, endocarditis and severe pneumonia.

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.

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.

Administration

Should be taken on an empty stomach. Take with a full glass of water on an empty stomach 1 hr before or 2 hr after meals. Do not take acidic beverages within 1 hr of a dose.

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

Hypersensitivity to benzylpenicillin and other penicillins.

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

Pregnancy category B. Either animal-reproduction studies have not demonstrated a fetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect that was not confirmed in controlled studies in women in the 1st trimester.

Lactation: Monitor electrolyte, hepatic, renal, cardiac and haematologic function; signs and symptoms of anaphylaxis during 1st dose.

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

Symptoms: Agitation, confusion, asterixis, hallucinations, stupor, coma, multifocal myoclonus, seizures and encephalopathy, hyperkalaemia.

Management: Symptomatic and supportive treatment.

Benzylpenicillin & Phenoxymethyl penicillin

Store between 20-25°C. Reconstituted soln: Store between 2-8°C.