Benzyl Penicillin
Indications
Benzyl Penicillin is used for:
Meningitis, Anthrax, Community-acquired pneumonia, Bacterial endocarditis, Septicemia, Diphtheria, Syphilis, Cellulitis, Infective endocarditis, Gonorrhea, Aspiration pneumonia, Lung abscess, Septic Arthritis, Gangrene, Meningococcal meningitis, Pneumococcal meningitis, Botulism
Adult Dose
Adult: IV Bacterial endocarditis W/ aminoglycoside: 1.2 g 4 hrly. Intrapartum prophylaxis against group B streptococcal infection Initial: 3 g, then 1.5 g 4 hrly until delivery.
Meningococcal meningitis; Pneumococcal meningitis 2.4 g 4 hrly. Up to 18 g/day in meningococcal meningitis.
IV/IM Susceptible infections 0.6-4.8 g/day in divided doses.
Child Dose
Infant & Children: Bacterial Infection
IV, IM 100,000–250,000 U/kg/day q4–6h
Max daily dose is 24 million U.
Renal Dose
Renal impairment: Dosing interval should be no more frequent than every 8-10 hr.
Administration
IM Administration
Do not inject near artery or nerve (may result in permanent neurologic damage)
Neonates, infants, small children: Midlateral aspect of thigh preferable
Older children and adults: Deep IM injection in upper outer quadrant of buttock
Because of high concentration of suspended matter, needle may be blocked if injection is not made at slow, steady rate
Reconstitution: Loosen the powd, then, hold the vial horizontally and rotate it while slowly directing the stream of diluent against the wall of the vial. Shake the vial vigorously after all the diluent has been added. Depending on the route of admin, reconstitute w/ sterile water for inj, NaCl 0.9% inj or dextrose 5% inj.
Contra Indications
Hypersensitivity to penicillins.
Precautions
Very high doses in poor renal function (risk of neurotoxicity) or heart failure. Avoid contact, skin sensitization may occur. Monitor serum potassium concentration, renal and haematological status. Spirochete infections particularly syphilis; suprainfection with penicillin-resistant organisms with prolonged use; avoid intrathecal route.
Lactation: Excreted into breast milk, caution advised
Pregnancy-Lactation
Interactions
Probenecid
Increases and prolongs serum penicillin levels.
Tetracycline
May antagonize the bactericidal effect of penicillin.
Adverse Effects
Side effects of Benzyl Penicillin :
Hypersensitivity reactions including uticaria; fever; joint pains; rashes; angioedema; serum sickness-like reactions; haemolytic anaemia; interstitial nephritis; neutropenia; thrombocytopenia; CNS toxicity including convulsions; diarrhoea; antibiotic-associated colitis.
Potentially Fatal: Anaphylaxis.
Mechanism of Action
Benzylpenicillin has a bactericidal action against gram-positive bacteria, gram-negative cocci, some other gram-negative bacteria, spirochetes and actinomycetes. It inhibits final 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 beta-lactamases.