Cimex/Cimex Plus Mechanism of Action

Pharmacology: Pharmacodynamics: Cimex: FC tablet: Cefuroxime axetil is the acetyloxyethyl ester of cefuroxime. Cefuroxime axetil belongs to the 2nd generation of cephalosporins and compared to the 1st generation of cephalosporins are not only active against gram-positive but also gram-negative organism. The mechanism of action of cefuroxime axetil, similar to all cephalosporins and it acts by combining with the penicillin bound proteins (PBP) part of the bacterial cell wall resulting in the lysis of the cell wall and as a consequence causing cell death and therefore having a bactericidal action. Axetil is the prodrug of the active compound cefuroxime. When given orally, cefuroxime axetil is hydrolyzed to cefuroxime by nonspecific esterases in the intestinal mucosa. Cefuroxime is distributed throughout the extracellular fluid. The axetil part is metabolized to acetaldehyde and acetic acid.
Oral suspension: Cefuroxime is bactericidal and has similar spectrum of antimicrobial action and pattern resistance to cefamandole. It is more resistant to hydrolysis by β-lactamases than cefamandole, and therefore may be more active against β-lactamase-producing strains of Haemophilus influenzae and Neisseria gonorrheae.
Pharmacokinetics: Cimex: FC tablet: Following oral administration, 30-50% of the drug is absorbed. Around 50% of the serum cefuroxime is protein bound. The C_max following oral administration of 250 mg and 500 mg of cefuroxime axetil in normal healthy adults is reported to be 4.1 and 7 mcg/mL and the t_max ranges from 2-3 hrs. The mean elimination t_½ is approximately 1.2 hrs for all doses. Cefuroxime is eliminated unchanged in the urine, and 50% of the administered dose is recovered in the urine in 12 hrs. The serum t_½ is therefore prolonged in patients with reduced renal function. However, no special precaution is necessary in patients with renal impairment or on renal dialysis or in the elderly at doses up to normal maximum of 1 g/day.
Oral suspension/Cimex Plus: Cefuroxime axetil is absorbed from the GIT and is rapidly hydrolyzed in the intestinal mucosa and blood to cefuroxime; absorption is enhanced in the presence of food. Peak plasma concentrations are reported about 2-3 hrs after an oral dose. Up to 50% of cefuroxime in the circulation is bound to plasma proteins. The plasma t_½ is about 70 min and is prolonged in patients with renal impairment and in neonates.
Cefuroxime is widely distributed in the body including pleural fluid, sputum, bone, synovial fluid and aqueous humor, but only achieves therapeutic concentrations in the cerebrospinal fluid when the meninges are inflamed. It crosses the placenta and has been detected in breast milk.
Cefuroxime is excreted unchanged, by glomerular filtration and renal tubular secretion and high concentrations are achieved in the urine. Probenecid competes for renal tubular secretion with cefuroxime resulting in higher and more prolonged plasma concentrations of cefuroxime. Small amounts of cefuroxime are excreted in bile. Plasma concentration are reduced by dialysis.
Microbiology: Cimex: FC tablet: Antibacterial Activity: Aerobic Gram-Positive Microorganisms: Staphylococcus aureus (including β-lactamase-producing strain, but not methicillin-resistant strains), Streptococcus pneumoniae, Streptococcus pyogenes.
Aerobic Gram-Negative Microorganisms: Escherichia coli, Haemophilus influenzae (including β-lactamase producing strain), Haemophilus parainfluenzae, Klebsiella pneumoniae, Moraxella catarrhalis, Neisseria gonorrheae (β-lactamase negative strains only).
In vitro activity is present against the following organisms: Staphylococcus epidermidis, Morganella morganii, Neisseria gonorrheae (β-lactamase-producing strains only), Proteus mirabilis.