Oral cephalosporins in perspective

Cefixime-induced angle closure and transient myopic shift in a healthy individual; A case report

Purpose

To report a case of Acute bilateral angle closure and Myopia following oral Cefixime therapy for pharyngitis.

Observation

A 49-year-old man presented to the clinic with a history of aggravating ocular pain and blurry vision in both eyes from 5 days ago. He was under treatment with oral Cefixime 400 mg twice a day for acute bacterial pharyngitis since last week. His refractive error was −3.75 and −4.25 diopters in the right and left eye respectively. Intraocular pressure (IOP) was 32 mm Hg in the right eye and 40 mm Hg in the left eye. Slit lamp examination and gonioscopy showed shallow anterior chamber with 360° appositional angle closure. Ultrasound biomicroscopy revealed shallow anterior chamber, narrow angle, supraciliary effusion and anterior rotation of ciliary body in both eyes. With diagnosis of drug-induced acute angle closure, oral Cefixime was discontinued and eye drops Betamethasone every 4 hours, Cosopt and Brimonidine twice a day, and Atropine 1% twice a day were started. Few days after starting treatment all ocular symptoms and signs were resolved.

Conclusions and importance

Systemic Cefixime can induce acute angle closure disease with myopic shift and elevated IOP secondary to supraciliary effusion and ciliary body rotation.

Cefuroxime axetil

Cefuroxime is the first commercially-available second-generation cephalosporine to be widely used in therapy; it is a semi-synthetic cephalosporin obtained from the 7-cephalosporanic acid nucleus of cephalosporin C. Cefuroxime axetil is the acetoxyethyl ester of cefuroxime. The majority of micro-organisms associated with respiratory infections are highly sensitive to cefuroxime. These include Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes and the other streptococci (excluding group D streptococci), and Moraxella catarrhalis. Bacteria sensitive to cefuroxime include the enterobacteria (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Salmonella and Shigella and Straphylococcus aureus (methicillin-sensitive strains). The pharmacokinetic studies show that the maximum plasma concentration of cefuroxime after oral administration of 250 mg and 500 mg of cefuroxime axetil after a meal are respectively 4.6 and 7.9 mg/l. The absolute bioavailability of tablets is 68% (extremes 63-73%) after oral administration of 500 mg cefuroxime axetil. The protein binding is 33+/-5.7%. Tissue diffusion was studied in the interstitial fluid, the bronchial mucosa, the tonsils, and the bronchial secretions. Cefuroxime axetil is available as capsule-shaped tablets containing 125, 250 or 500 mg. An oral suspension dosage form for paediatric purposes is also available as granules in multidose bottles and sachets. Constitution gives a suspension containing 125 mg or 250 mg cefuroxime (as cefuroxime axetil). Cefuroxime axetil is indicated for the treatment of infections caused by susceptible bacteria. Indications include: lower respiratory tract infections (e.g., acute and chronic bronchitis and pneumonia); upper respiratory tract infections (e.g., ear, nose and throat infections such as otitis media, sinusitis tonsillitis and pharyngitis); genito-urinary tract infections (e.g., pyelonephritis, cystitis and urethritis, gonorrhoea, acute uncomplicated gonococcal urethritis and cervicitis); and skin and soft tissue infections (e.g., furunculosis, pyoderma and impetigo). For most infections, a dose of 250 mg twice daily is appropriate. In some urinary tract infections, 125 mg twice daily has been shown to be effective. If pneumonia is suspected or in more severe lower respiratory tract infection, doses of 500 mg bd should be used. Uncomplicated gonorrhoea has been shown to respond to a single 1-g dose of cefuroxime axetil. Adverse reactions to cefuroxime have generally been mild and transient in nature (gastrointestinal disturbances, including diarrhoea, nausea and vomiting).

Novel oral cephalosporins

The therapeutic use of oral cephalosporins to treat infectious diseases continues to challenge clinicians; many attempts have been made over recent years to improve the efficacy and spectrum of these anti-infectives. Many oral cephalosporins are in development and include cefdinir, cefprozil, cefetamet pivoxil, cefcapene pivoxil, cefcanel daloxate hydrochloride in Phase II trials, S-1090 in Phase III trials and the novel compounds E1100, E1101 and BRL-57347. Differences between these drugs are sometimes subtle and the improvement over existing compounds modest, although recent cephalosporins have shown greater activity against Gram-negative bacterial infections. A better knowledge of the pharmacodynamic and pharmacokinetic interrelationships of existing oral cephalosporins is demanded for a more rational use of these compounds and to avoid the subsequent development of resistance. Perhaps with such an approach, the perceived need for new cephalosporins will diminish.

Cefuroxime axetil. A review of its antibacterial activity, pharmacokinetic properties and therapeutic efficacy

Cefuroxime axetil is an oral cephalosporin which is rapidly hydrolysed to the active parent compound, cefuroxime. Cefuroxime has a broad spectrum of in vitro antibacterial activity which encompasses methicillin-sensitive staphylococci and the common respiratory pathogens Streptococcus pneumoniae, Haemophilus influenzae, Moraxella (Branhamella) catarrhalis and group A beta-haemolytic streptococci. Cefuroxime has broad spectrum activity against the beta-lactamase positive respiratory pathogens H. influenzae and M. catarrhalis; it is also active against penicillin-susceptible and -intermediate strains of S. pneumoniae. In clinical trials, cefuroxime axetil (administered twice daily) has been evaluated in the treatment of upper and lower respiratory tract infections and has demonstrated similar efficacy to established antibacterial agents, including amoxicillin/clavulanic acid and cefaclor. Five days' treatment with cefuroxime axetil was recently shown to be as effective as 10 days' treatment with either cefuroxime axetil or amoxicillin/clavulanic acid in patients with acute otitis media or acute bronchitis. Cefuroxime axetil was at least as effective as phenoxymethylpenicillin (penicillin V) in the treatment of patients with group A beta-haemolytic streptococcal tonsillopharyngitis. A number of studies have evaluated the efficacy of cefuroxime axetil as the oral component of intravenous to oral sequential therapy in hospitalised patients with lower respiratory tract infection. In each study patients received parenteral cefuroxime for approximately 2 days followed by cefuroxime axetil for 5 to 10 days. In comparative studies, cefuroxime sequential therapy was as effective as amoxicillin/ clavulanic acid sequential therapy and full courses of parenteral cefuroxime, cefotiam or cefoperazone. Adults with urinary tract infections and skin infections were also effectively treated with cefuroxime axetil, as were adults and adolescents with early stage lyme disease. Cefuroxime axetil is associated with a low incidence of adverse events, with gastrointestinal disturbances being the most frequently observed. Thus, cefuroxime axetil is an effective and convenient treatment for a wide range of infections and may be considered a therapeutic option when empirical treatment of community-acquired infections is required. Moreover, given the promising results of several intravenous/oral sequential treatment studies, cefuroxime axetil may also become established as an oral component of sequential treatment regimens.

Cephalosporin antimicrobial agents and related compounds

Cephalosporins are broad-spectrum antimicrobial agents that are often used empirically to treat suspected bacterial infections and also to treat culture-proven infections due to selected gram-positive and gram-negative microorganisms. Cephalosporins differ widely in their spectrum of activity, susceptibility to beta-lactamases, serum half-life, and penetration of the central nervous system. In general, the first-generation and second-generation agents are most active against staphylococci and streptococci, and the third-generation agents are most active against the Enterobacteriaceae and Pseudomonas. As a group, cephalosporins have a favorable profile of toxicity in comparison with other antimicrobial agents. The development of bacterial resistance has affected all steps of the cephalosporin mechanism of action, including production of beta-lactamases, alterations in penicillin-binding proteins, and modification of the cell wall. New cephalosporins are among the most expensive pharmaceutical agents in use today. Maintaining expertise in the choice and use of these agents will remain a challenge to physicians as additional investigational cephalosporins continue to be developed and introduced into clinical practice.