Altamax Mechanism of Action

Pharmacology: Pharmacokinetics: The average plasma concentrations of cefepime observed in healthy adult male volunteers (n=9) at various times following single 30 minute infusions (IV) of cefepime 500 mg, 1 g, and 2 g are summarized in Table 1. Elimination of cefepime is principally via renal excretion with an average (±SD) half-life of 2.0 (±0.3) hours and total body clearance of 120.0 (±8.0) mL/min in healthy volunteers. Cefepime pharmacokinetics are linear over the range 250 mg to 2 g. There is no evidence of accumulation in healthy adult male volunteers (n=7) receiving clinically relevant doses for a period of 9 days.
Absorption: The average plasma concentrations of cefepime and its derived pharmacokinetic parameters after intravenous (IV) administration are portrayed in Table 1. (See Table 1.)

Click on icon to see table/diagram/image
Following intramuscular (IM) administration, cefepime is completely absorbed. The average plasma concentrations of cefepime at various times following a single intramuscular injection are summarized in Table 2. The pharmacokinetics of cefepime are linear over the range of 500 mg to 2 g intramuscularly and do not vary with respect to treatment duration. (See Table 2.)

Click on icon to see table/diagram/image

Distribution: The average steady-state volume of distribution of cefepime is 18.0 (±2.0) L. The serum protein binding of cefepime is approximately 20% and is independent of its concentration in serum.
Cefepime is excreted in human milk. A nursing infant consuming approximately 1000 mL of human milk per day would receive approximately 0.5 mg of cefepime per day.
Concentrations of cefepime achieved in specific tissues and body fluids are listed in Table 3. (See Table 3.)

Click on icon to see table/diagram/image

Data suggest that cefepime does cross the inflamed blood-brain barrier. The clinical relevance of these data are uncertain at this time.
Metabolism and Excretion: Cefepime is metabolized to N-methylpyrrolidine (NMP) which is rapidly converted to the N-oxide (NMP-N-oxide). Urinary recovery of unchanged cefepime accounts for approximately 85% of the administered dose. Less than 1% of the administered dose is recovered from urine as NMP, 6.8% as NMP-N-oxide, and 2.5% as an epimer of cefepime. Because renal excretion is a significant pathway of elimination, patients with renal dysfunction and patients undergoing hemodialysis require dosage adjustment.
Microbiology: Cefepime is a bactericidal agent that acts by inhibition of bacterial cell wall synthesis. Cefepime has a broad spectrum of in vitro activity that encompasses a wide range of Gram-positive and Gram-negative bacteria. Cefepime has a low affinity for chromosomally-encoded beta-lactamases. Cefepime is highly resistant to hydrolysis by most beta-lactamases and exhibits rapid penetration into Gram-negative bacterial cells. Within bacterial cells, the molecular targets of cefepime are the penicillin binding proteins (PBP).
Cefepime has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections as described in Indications/Uses.
Aerobic Gram-Negative Microorganisms: Enterobacter; Escherichia coli; Klebsiella pneumoniae; Proteus mirabilis; Pseudomonas aeruginosa.
Aerobic Gram-Positive Microorganisms: Staphylococcus aureus (methicillin-susceptible isolates only); Streptococcus pneumoniae; Streptococcus pyogenes (Lancefield's Group A streptococci); Viridans group streptococci.
The following in vitro data are available, but their clinical significance is unknown. Cefepime has been shown to have in vitro activity against most isolates of the following microorganisms; however, the safety and effectiveness of cefepime in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled trials.
Aerobic Gram-Positive Microorganisms: Staphylococcus epidermidis (methicillin-susceptible isolates only); Staphylococcus saprophyticus; Streptococcus agalactiae (Lancefield's Group B streptococci).
NOTE: Most isolates of enterococci, eg, Enterococcus faecalis, and methicillin-resistant staphylococci are resistant to cefepime.
Aerobic Gram-Negative Microorganisms: Acinetobacter calcoaceticus subsp. Iwoffii; Citrobacter diversus; Citrobacter freundii; Enterobacter agglomerans; Haemophilus influenzae (including beta-lactamase producing isolates); Hafnia alvei; Klebsiella oxytoca; Moraxella catarrhalis (including beta-lactamase producing isolates); Morganella morganii; Proteus vulgaris; Providencia rettgeri; Providencia stuartii; Serratia marcescens.
NOTE: Cefepime is inactive against many isolates of Stenotrophomonas (formerly Xanthomonas maltophilia and Pseudomonas maltophilia).
Anaerobic Microorganisms: NOTE: Cefepime is inactive against most isolates of Clostridium difficile.