Crystapen, Pencillin Sodium Biochemie
|Reviewed by Dr Carl Kuschel, Dorothy Cooper|
Add an aminoglycoside if tolerance is suspected/confirmed.
≤29 0 to 28 12 >28 8 30 to 36 0 to 14 12 >14 8 37 to 44 0 to 7 12 >7 8 ≥45 All 6
Benzylpenicillin has bacteriostatic/bacteriocidal actions (depending on its concentration) against most gram positive bacteria and gram negative cocci. Also active against some spirochaetes and actinomycetes. Action through inhibition of biosynthesis of cell wall mucopeptide. Its action is inhibited by the enzyme penicillinase, produced during the growth of certain micro-organisms.
Well absorbed following intramuscular injection. Widely distributed at varying concentrations in body tissues and fluids. Very little passes into the CSF unless the meninges are inflamed. Moderate binding (45-65%) to human plasma protein. Rapidly excreted via the kidney, mainly unchanged. Tubular excretion is inhibited by probenecid. Reduction in serum concentrations can be achieved by haemodialysis. Half life 5-6 hours in healthy newly born preterm infants and 2 hours in full term babies > 1-2 weeks old.