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DISTACLOR Capsules (2018)

Pharmacodynamic properties

Pharmacotherapeutic group: Second-generation cephalosporins antibiotics
ATC code: J01DC04

Mechanism of action

Cefaclor is active against the following organisms in vitro:

Alpha- and beta-haemolytic streptococci
Staphylococci; including coagulase-positive, coagulase-negative and penicillinase-producing strains
Streptococcus pneumoniae
Streptococcus pyogenes (group A beta-haemolytic streptococci)
Branhamella catarrhalis
Escherichia coli
Proteus mirabilis
Klebsiella species
Haemophilus influenzae, including ampicillin-resistant strains

Cefaclor has no activity against Pseudomonas species or Acinetobacter species. Methicillin-resistant staphylococci and most strains of enterococci (eg, Str. faecalis) are resistant to cefaclor. Cefaclor is not active against most strains of Enterobacter spp, Serratia spp, Morganella morganii, Proteus vulgaris and Providencia rettgeri.

Pharmacokinetic properties

Absorption

Cefaclor is well absorbed after oral administration to fasting subjects. Total absorption is the same whether the drug is given with or without food; however, when it is taken with food, the peak concentration achieved is 50-75% of that observed when the drug is administered to fasting subjects and generally appears from ¾ to one hour later.

Linearity

Following administration of 250mg, 500mg and 1G doses to fasting subjects, average peak serum levels of approximately 7, 13 and 23 mg/L respectively were obtained within 30-60 minutes.

Biotransformation and Elimination

Approximately 60-85% of the drug is excreted unchanged in the urine within eight hours, the greater portion being excreted within the first two hours. During the eight hour period, peak urine concentrations following the 250mg, 500mg and 1G doses were approximately 600, 900 and 1,900 mg/L respectively. The serum half-life in normal subjects is 0.6-0.9 hours. In patients with reduced renal function, the serum half-life of cefaclor is slightly prolonged. In those with complete absence of renal function, the plasma half-life of the intact molecule is 2.3-2.8 hours. Excretion pathways in patients with markedly impaired renal function have not been determined. Haemodialysis shortens the half-life by 25-30%.

Preclinical safety data

Non-clinical data reveal no special hazard for humans based on conventional studies of safety pharmacology, repeated dose toxicity, genotoxicity, carcinogenic potential, toxicity to reproduction and development.