Pharmacology for Dentistry

Tetracyclines, Chloramphenicol and Chemotherapy of UTI 313

ducreyi, granuloma inguinale caused by

Calymmatobacterium granulomatis.

As an alternative drug in the treatment

of gonorrhoea and syphilis in patients

allergic to penicillin.

4. Dermatological infections: Acne
   vulgaris, when antibiotic therapy is
   considered necessary.


5. Ophthalmic infections: Due to suscep-
   tible strains of N. gonorrhoeae, staphy-
   lococci, H. influenzae and in the treat-
   ment of trachoma.


6. Prophylaxis and treatment of Traveller’s
   diarrhoea.


7. Miscellaneous infections caused by
   susceptible strains of bacteria causing
   psittacosis, cholera, melioidosis, lep-
   tospirosis, brucellosis, bartonellosis,
   plague, tularemia, Campylobacter fetus
   infection, rickettsial infections including
   typhus and Q fever, relapsing fever due
   to Borrelia recurrentis and actinomyco-
   sis in penicillin allergic patients.


8. As an adjunct in acute intestinal
   amoebiasis.


9. Prophylaxis of malaria due to P.
   falciparum.

CHLORAMPHENICOL

It is a broad spectrum antibiotic originally
derived from Streptomyces venezuelae and later
on became the first completely synthetic
antibiotic. It is used as palmitate and sodium
succinate salt in given dosage.

Dose: 250-500 mg QID oral, 1-2 g IM
injection, 0.5-1.0% topical (eye ointment/
drops/applicap and ear drops).

Chloramphenicol is a potent inhibitor of
microbial protein synthesis. It acts by

binding reversibly to the 50S submit of the

bacterial ribosome. It inhibits the peptidyl

transferase step of protein synthesis. It is

bacteriostatic broad-spectrum antibiotic

active against gram positive and negative

organisms, Rickettsia, the Chlamydia of the

psittacosis, lymphogranuloma group and

Mycoplasma pneumoniae. The other organisms

sensitive to chloramphenicol are E. coli, K.

pneumoniae, Shigella, and certain strains of

Brucella, Pasteurella, Proteus and Vibrio comma.

It exerts bactericidal against H. influenzae,

Strep. pneumoniae and N. meningitidis.

Pharmacokinetics

Chloramphenicol is completely absorbed

after oral administration, bound to plasma

protein (approximately 60%) and widely

distributed in body. It crosses the blood-brain

and placental barrier and shows its presence

in CSF, bile and milk. It is conjugated with

glucuronic acid in liver and excreted in urine.

Small amount is excreted in urine in

unchanged form.

Adverse Effects

Allergic reaction includes skin rashes,

drug fever, dermatitis, angioneurotic

edema.

Bone marrow depression includes

aplastic anaemia, leukopenia, agranulocy-

tosis, thrombocytopenia.

Gray baby syndrome: Premature babies

develop vomiting, hypothermia, abdominal

distension, shallow irregular respiration and

further leading to gray cyanosis, vascular

collapse, shock and death.

CNS toxicity includes headache, mental

confusion, internal ophthalmoplegia, periph-

eral neuritis, depression, optical neuritis.