Tags: Cephradine

Streptococcus Pyogenes

Streptococcus pyogenes is a human pathogen without an animal reservoir. Group A streptococci (GAS) cause most streptococcal disease, but other groups are important pathogens in some settings (Box 1). Group A streptococcal infections have the highest incidence in children younger than age 10. The asymptomatic prevalence is also higher (15-20%) in children, compared with that in adults (<5%).

Anti-Infective Agent Dosing

The characteristics that need to be considered when administering antibiotics include absorption (when dealing with oral antibiotics), volume of distribution, metabolism, and excretion. These factors determine the dose of each drug and the time interval of administration. To effectively clear a bacterial infection, serum levels of the antibiotic need to be maintained above the minimum inhibitory concentration for a significant period. For each pathogen, the minimum inhibitory concentration is determined by serially diluting the antibiotic into liquid medium containing 104 bacteria per millihter.

Specific Anti-Infective Agents

Clinicians should be familiar with the general classes of antibiotics, their mechanisms of action, and their major toxicities. The differences between the specific antibiotics in each class can be subtle, often requiring the expertise of an infectious disease specialist to design the optimal anti-infective regimen. The general internist or physician-in-training should not attempt to memorize all the facts outlined here, but rather should read the pages that follow as an overview of anti-infectives. The chemistry, mechanisms of action, major toxicities, spectrum of activity, treatment indications, pharmacokinetics, dosing regimens, and cost are reviewed.

Urinary Tract Infections and Prostatitis

A urinary tract infection is defined as the presence of microorganisms in the urine that cannot be accounted for by contamination. The organisms have the potential to invade the tissues of the urinary tract and adjacent structures.

Antimicrobial Regimen Selection

A generally accepted systematic approach to the selection and evaluation of an antimicrobial regimen is shown in Table Systematic Approach for Selection of Antimicrobials. An «empiric» antimicrobial regimen is begun before the offending organism is identified, while a «definitive» regimen is instituted when the causative organism is known. The use of combinations to prevent the emergence of resistance is widely applied but not often realized. The only circumstance where this has been clearly effective is in the treatment of tuberculosis.

Antimicrobial therapy: general principles

A wide variety of antimicrobial agents is available to treat established infections caused by bacteria, fungi, viruses, or parasites. This section will cover the general principles of antimicrobial therapy and will also include illustrative clinical problems to emphasize proper decision-making in using antimicrobials.

Toxicity of Antimicrobial Therapy

The mechanisms associated with common adverse reactions to antimicrobials include dose-related toxicity that occurs in a certain fraction of patients when a critical plasma concentration or total dose is exceeded, and toxicity that is unpredictable and mediated through allergic or idiosyncratic mechanisms. For example, certain classes of drugs such as the aminoglycosides are associated with dose-related toxicity.


The drug should not be used alone for empiric therapy in seriously ill patients if there is a possibility that the infection may be caused by gram-positive bacteria or if a mixed aerobic-anaerobic bacterial infection is suspected. In such infections, another anti-infective agent effective against the suspected, potentially aztreonam-resistant organism should initially be used concomitantly. Aztreonam has been used safely and effectively in conjunction with an aminoglycoside, clindamycin, erythromycin, metronidazole, a penicillin, or vancomycin.

Order Suprax (Cefixime) No Prescription 100/200mg

The drug also is used for the treatment of uncomplicated gonorrhea and has been used in the treatment of infections caused by susceptible Salmonella or Shigella. Because cefixime has a long serum half-life and can be administered once or twice daily, some clinicians suggest that the drug may be particularly useful when patient compliance is a concern (e.g., in the treatment of otitis media). Although cefixime is an effective alternative to other anti-infective agents for the treatment of many infections, the drug offers no clear advantage (except for a convenient dosage regimen) over other equally effective, less expensive anti-infectives available for the treatment of uncomplicated urinary tract infections or upper and lower respiratory tract infections.


Cephradine is administered orally. Cephradine also has been administered by IM or IV injection and by IV infusion, but a parenteral dosage form no longer is commercially available in the US. For lobar pneumonia and serious urinary tract infections (including prostatitis), the usual adult oral dosage is 500 mg every 6 hours or 1 g every 12 hours. For severe or chronic infections, dosage may be increased up to 1 g every 6 hours.