Antibacterial drugs

IM penicillin G benzathine is used only for the treatment of mild to moderately severe infections caused by organisms susceptible to low concentrations of penicillin G, for prophylaxis of infections caused by these organisms, or as follow-up therapy to IM or IV penicillin G potassium or sodium. When high concentrations of penicillin G are required, parenteral penicillin G potassium or sodium should be used. For specific information on the uses of penicillin G benzathine, see Uses in the Natural Penicillins General Statement 8:12.16.04.

Based on Spectra of Activity Penicillins are natural or semisynthetic antibiotics produced by or derived from certain species of the fungus Penicillium. The drugs are b-lactam antibiotics structurally and pharmacologically related to other b-lactam antibiotics including cephalosporins and cephamycins.

Dosage of troleandomycin is expressed in terms of oleandomycin. The usual adult dosage is 250-500 mg every 6 hours. The usual dosage in children is 125-250 mg every 6 hours. Alternatively, children may receive 6.6-11 mg/kg every 6 hours.

Dirithromycin is a semisynthetic macrolide antibiotic that is structurally and pharmacologically related to erythromycin. Dirithromycin is hydrolyzed nonenzymatically during intestinal absorption almost entirely to erythromycyclamine, which is microbiologically active.

Clarithromycin is used orally for the treatment of pharyngitis and tonsillitis, mild to moderate respiratory tract infections (acute bacterial exacerbation of chronic bronchitis, acute maxillary sinusitis, community-acquired pneumonia), uncomplicated skin and skin structure infections, and acute otitis media caused by susceptible organisms.

Oral azithromycin also is used for the treatment of urethritis or cervicitis caused by Chlamydia trachomatis or Neisseria gonorrhoeae, and for the treatment of chancroid caused by Haemophilus ducreyi. Azithromycin is used orally for the treatment of disseminated infections caused by Mycobacterium avium complex (MAC) in patients with human immunodeficiency virus (HIV) infection and for prevention of disseminated MAC infection (both primary and secondary prophylaxis) in HIV-infected individuals. Azithromycin is used orally in children for the treatment of acute otitis media, community-acquired pneumonia, and pharyngitis or tonsillitis caused by susceptible organisms.

Erythromycin stearate is administered orally. Optimal absorption occurs when the drug is administered in the fasting state or immediately before a meal. The usual adult dosage of erythromycin as the stearate is 250 mg every 6 hours or 500 mg every 12 hours.

Erythromycin lactobionate is administered by continuous or intermittent IV infusion. Because of the local irritative effects of erythromycin, the drug must not be administered rapidly by direct IV injection (IV push). Oral erythromycin therapy should replace IV erythromycin lactobionate therapy as soon as possible.

Erythromycin ethylsuccinate is administered orally. Erythromycin ethylsuccinate oral suspensions, chewable tablets, and film-coated tablets may be administered without regard to meals. Chewable tablets should not be swallowed whole. The fixed-combination preparation containing erythromycin ethylsuccinate and sulfisoxazole acetyl is administered orally and may be given without regard to meals.

Dosage of erythromycin estolate is expressed in terms of erythromycin. The usual adult oral dosage of erythromycin as the estolate is 250 mg every 6 hours. In severe infections, dosage may be increased to 4 g or more daily.