(1997; 132 pages) [French] [Spanish]
Benzylpenicillin: powder for injection, 600 mg (=1 million IU), 3g (=5 million IU) (as sodium or potassium salt) in 5-ml vial
Benzathine benzylpenicillin: powder for injection, 1.44 g of benzylpenicillin (=2,4 million IU) in 5-ml vial
Procaine benzylpenicillin: powder for injection, 1 g (=1 million IU), 3g (=3 million IU) in vial
Benzylpenicillin is a β-lactam antibiotic produced by Penicillin spp. It is bactericidal against streptococci, neisseriae, many anaerobes and spirochaetes.
After intramuscular injection, peak plasma concentrations are reached within 15-30 minutes. It is widely distributed throughout the body, has a plasma half-life of 30 minutes and is excreted mainly in the urine.
Repository formulations of benzyl-penicillin are available for parenteral use. They are designed to provide a tissue depot from which the drug is slowly absorbed over a period of 12 hours to several days. Procaine benzylpenicillin produces a peak plasma concentration within 1-3 hours and is excreted over a period of several days, while benzathine benzylpenicillin takes 13-24 hours to reach its peak plasma concentration and is detectable in the urine for 3-4 weeks.
• severe pyodermas caused by susceptible organisms
• yaws and other non-venereal treponematoses
• impetigo caused by Streptococcus pyogenes
• tropical ulcers.
Dosage and administration
Benzylpenicillin and its repository formulations must be administered parenterally.
The powder for injection should be diluted in “water for injection” in accordance with the manufacturer’s instructions.
Adults and children over 12 years: benzylpenicillin 2 million IU i.v. daily in four divided doses for 10-14 days.
Children under 12 years: benzylpenicillin 100 mg/kg i.m. daily in four divided doses for 10-14 days.
Adults: benzathine benzylpenicillin 2.4 million IU in two i.m. injections in a single session.
Children: benzathine benzylpenicillin 1.2 million IU in two i.m. injections in a single session.
Impetigo caused by Streptococcus pyogenes:
Adults and children over 12 years: procaine benzylpenicillin 600000 IU i.m. daily in a single dose for at least 10 days.
Children under 12 years: procaine benzylpenicillin 25000-50000 IU/kg i.m. daily in a single dose for at least 10 days.
Adults and children over 12 years: procaine benzylpenicillin 600000 IU i.m. daily in a single dose for 2-4 weeks.
Children under 12 years: procaine benzylpenicillin 25 000-50 000 IU/kg i.m. daily in a single dose for 2-4 weeks.
Known hypersensitivity to penicillins or cefalosporins.
Facilities should be available for treating anaphylaxis whenever penicillins are used. Patients should be questioned carefully about previous allergic reactions before the first dose is administered. If a skin rash develops during treatment, the patient should be transferred to a different class of antibiotic.
Use in pregnancy
There is no evidence that benzyl-penicillin or its repository formulations are teratogenic. They may be used during pregnancy.
Hypersensitivity reactions range in severity from skin rashes to immediate anaphylaxis.
Pain and sterile inflammation can occur at the site of intramuscular injection; phlebitis or thrombophlebitis sometimes follows intravenous administration of benzylpenicillin. Accidental injection into a peripheral nerve causes severe pain and dysfunction.
Rapid intravenous administration of large doses of benzylpenicillin may cause hyperkalaemia, dysrhythmias and cardiac arrest, particularly in patients with impaired renal function. Accidental intravascular administration of procaine benzylpenicillin or benzathine benzylpenicillin may produce convulsions.
Unduly high concentrations of benzylpenicillin in the brain can result in confusion, convulsions, coma and fatal encephalopathy. The procaine component has been implicated in acute mental disturbances associated with the administration of large single doses.
Interstitial nephritis, neutropenia and thrombocytopenia have been reported.
Overdosage can cause convulsions, paralysis and even death.
Emesis and gastric lavage may be of value if begun within a few hours of injection. Excessive blood concentrations can be lowered by haemodialysis.
Powder for injection should be stored in vials at 2-8 °C.