i. When any of the aminoglycosides are used, concomitant use with general
anesthetics or neuromuscular blocking agents should be monitored because of
recognized drug interactions. Additionally, the use of rapidly acting diuretics should be
avoided, as ototoxicity and nephrotoxicity can be potentiated with their use. Renal
functions should be monitored continuously when these agents are used.
j. Spectinomycin (Trobicin) has an action similar to that of the
aminoglycosides but without bactericidal action. It is used in the treatment of gonorrhea
in patients that are hypersensitive to penicillin and cannot tolerate one of the
tetracyclines. It is also used in the treatment of penicillinase producing Neisseria
gonorrhea (PPNG). Spectinomycin is usually given in a single IM dose, the strength of
which is dependent on unknown resistance factors. There are very few adverse
reactions of any significance associated with the use of this agent. However, it should
not be used in the treatment of syphilis, and its safety in pregnant women has not been
established.
3-13. TETRACYCLINES
a. These drugs originate from strains of Streptomyces containing broth that is
fermented in deep tanks. Most of these agents are the result of chemical modifications
of the broth by product. All of them are bacteriostatic. Their MOA is to inhibit protein
synthesis in the microorganism.
b. If administered orally, absorption of these agents occurs primarily in the
stomach and the upper portion of the small intestine. Administration intravenously
results in wide distribution of the agent throughout the body, with penetration of the
CSF.
c. Excretion of these agents occurs through either the urinary or the biliary tract,
with the urinary tract as the primary route. Doxycycline is excreted almost exclusively
through the feces. Minocycline appears to be the only agent that is metabolized,
whereas the others are excreted unchanged.
d. The tetracyclines are true broad-spectrum antibiotics effective against gram
positive and gram-negative bacteria. Agents in this group are the drugs of choice when
treating Mycoplasma pneumoniae, chlamydia, cholera, and Rocky Mountain spotted
fever. They are also used in the treatment of gonorrhea in patients hypersensitive to
penicillin and in high doses in the treatment of syphilis in patients hypersensitive to
penicillin.
MD0808
3-12