The
tetracyclines are effective in the treatment of Chlamydia, Mycoplasma pneumoniae, and rickettsial
infections and may also be used for gonococcal
infections in patients unable to tolerate
penicillins. These drugs may cause gastrointestinal irritation, photo-toxic
dermatitis,
diarrhea, vestibular damage, and hepatotoxicity in pregnant women.
Chloramphenicol is used primarily for anaerobic
infections, Haemophilus influenzae
meningitis, and
typhoid fever. The most important toxic effect of
chloramphenicol is bone marrow suppression, which can be dose related or idiosyncratic.
Erythromycin is the
drug of choice for the treatment of
infections caused by M. pneumoniae, Legionella species, group A beta-hemolytic streptococci, and Streptococcus pneumoniae. The frequency of serious untoward effects associated with the use of
erythromycin is low; epigastric distress may occur.
Clindamycin is active against Bacteroides fragilis and other anaerobic microorganisms.
Pseudomembranous enterocolitis has developed in as many as 10% of patients taking this
drug. The use of
clindamycin should be discontinued promptly if
diarrhea occurs.