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.
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.
Chloramphenicol should be used only for the treatment of serious infections caused by susceptible bacteria or Rickettsia when potentially less toxic drugs are ineffective or contraindicated. The drug must not be used for the treatment of trivial infections, as a prophylactic agent to prevent bacterial infections, or when it is not indicated as in the treatment of colds, influenza, or throat infections.
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.