e. Gastrointestinal reactions are common with the use of tetracyclines. Some of
these conditions are epigastric distress, nausea, vomiting, diarrhea, and general
abdominal discomfort. Hepatic and renal toxicity, photosensitivity, permanent
discoloration of the teeth in pediatric patients or fetus, CNS vestibular disturbances, and
other local irritations are additional adverse reactions associated with the use of these
f. Tetracyclines should not be used in children during tooth development, which
occurs in the last half of pregnancy, infancy, and through childhood up to 8 years of
age. The tetracyclines can cross the placenta and have direct toxic effects on the
bones of the developing fetus. They also appear in the milk of lactating mothers.
Antacids, milk, dairy products, iron, or foods containing aluminum, calcium, or
magnesium should be avoided when these agents are taken orally. The tetracyclines
should never be used with the penicillins.
g. Tetracyclines appear in the following preparations:
Tetracycline HCl (Achromycin, Tetracyn, Sumycin)
3-14. CHLORAMPHENICOL (CHLOROMYCETIN).
a. This drug is produced by Streptomyces venezuelae, an organism first isolated
in 1947 from a soil sample collected in Venezuela. It is bacteriostatic for most
organisms and works by inhibiting protein synthesis.
b. Chloramphenicol is absorbed well by the body when it is administered orally.
When it is administered IM, its absorption is questionable; therefore parenteral doses
should be given IV. Distribution is generally good in all body fluids with concentration in
the liver and kidneys. Therapeutic levels are achieved in the CSF without inflammation.
Measurable levels can be detected in aqueous, vitreous humors, and bile.
c. During the metabolic process, most of the drug unites with glucuronic acid,
and the free drug and metabolites are excreted through the urine.
d. Chloramphenicol is used in the treatment of serious infections such as
meningitis and is the drug of choice in the treatment of typhoid fever.