BENPEN

What it is

BENPEN is benzylpenicillin sodium, a powder for injection. BENPEN contains no antiseptic or buffering agent nor are there any excipients. BENPEN is a fine white to off-white homogenous powder, which is soluble in water. The injection is prepared by the addition of the appropriate volume of Water for Injections to give the desired concentration of benzylpenicillin.

Approved indications —

Treatment of infections caused by benzylpenicillin-sensitive organisms, including Streptococcus pyogenes and most other Gram-positive organisms. — Treatment of syphilis. — Prevention of bacterial endocarditis in dental and upper respiratory tract procedures. — Prevention of wound infections and sepsis in surgical procedures where Streptococci are the likely pathogens.

Dosing overview

For adults and children aged 10 years and over, the minimum dosage is 300 mg six hourly. For children aged 3 to 10 years, the minimum dosage is 150 to 300 mg six hourly. For children under 3 years, the minimum dosage is 60 mg six hourly. For premature babies and neonates, the minimum dosage is 30 to 60 mg twelve hourly. For severe infections or where more resistant organisms are involved, the dose may be increased in amount and frequency of administration. For meningococcal meningitis in children, the initial dose is 600 mg followed by 300 mg intramuscularly every 4 to 6 hours. For pneumococcal meningitis, at least 300 mg should be given every 4 hours for 14 days and then every 6 hours for 7 days. For subacute bacterial endocarditis, prolonged treatment is required with not less than 1.2 g daily in divided doses. Patients with highly sensitive organisms should be given intravenous BENPEN for 4 to 6 weeks in doses of 6 to 12 g daily. For antimicrobial prophylaxis in surgery where likely pathogens are Streptococci, 600 mg BENPEN should be given intravenously immediately prior to surgery. For prolonged operations the same dose may be given 4 to 8 hourly for the duration of the procedure.

Key safety warnings

Serious and occasionally fatal hypersensitivity reactions including anaphylaxis have been reported in patients receiving beta-lactam antibiotics. Although anaphylaxis is more frequent following parenteral therapy, it has occurred in patients on oral therapy. Before commencing therapy with any beta-lactam antibiotic, careful enquiries should be made concerning previous hypersensitivity reactions to penicillins, cephalosporins or other allergens. Serious anaphylactoid reactions require emergency treatment with adrenaline. Oxygen, intravenous steroids and airway management including intubation, should also be administered as indicated. Antibiotic-associated pseudomembranous colitis has been reported with many antibiotics including benzylpenicillin. A toxin produced by Clostridium difficile appears to be the primary cause. The severity of the colitis may range from mild to life threatening. It is important to consider this diagnosis in patients who develop diarrhoea or colitis in association with antibiotic use, which may occur up to several weeks after cessation of antibiotic therapy. Disturbances of blood electrolytes may follow the administration of large doses of sodium salts of benzylpenicillin. Each 1 gram dose of BENPEN contains 3.0 mmol of sodium. In prolonged therapy with benzylpenicillin and particularly with high dosage schedules, periodic evaluation of the electrolyte balance, renal and haematopoietic systems is recommended. Severe cutaneous adverse reactions such as Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms, and acute generalised exanthematous pustulosis have been reported in patients taking beta-lactam antibiotics. When SCAR is suspected, benzylpenicillin should be discontinued immediately and an alternative treatment should be considered.

Contraindications

History of hypersensitivity reactions to beta-lactam antibiotics.

PBS listing

BENPEN is listed on the PBS in two strengths: powder for injection 600 mg as sodium with 3 PBS items at an ex-manufacturer price of A$5.52, and powder for injection 3 g as sodium with 3 PBS items at an ex-manufacturer price of A$8.91. Both strengths are unrestricted.

Regulatory history

BENPEN was first registered on the Australian Register of Therapeutic Goods on 4 November 1991, with three presentations: 600 mg, 1.2 g and 3 g powder for injection vials.