Pharmacology for Dentistry

312 Section 9/ Chemotherapy

V. cholerae, E. coli, Enterobacter aerogenes,
Shigella sp. are also highly sensitive. Atypical
bacteria e.g. Chlamydia sp., Mycoplasma sp.,
Ureaplasma urealyticum as well as Rickettsia
are extremely sensitive to tetracycline.
Besides being highly effective against a wide
range of gram positive and negative
organisms, tetracycline is effective against
all bacteria responsible for sexually
transmitted diseases viz. syphilis,
gonorrhoea, chancroid and nongonococcal
urethritis. It is effective/synergistic with
specific drugs against even protozoa and
fungi. Though effective against a number of
anaerobes it can not be relied upon as sole
therapy of anaerobic infections. Tetracycline
is not effective against viruses, Pseudomonas,
Proteus and Klebsiella.

Pharmacokinetics

The absorption of tetracycline
administered orally is variable and depend
upon the type of tetracycline used. The
tetracycline form insoluble complexes i.e.
chelation with calcium, magnesium, milk
and antacids reduce their absorption.
Administration of iron also interferes with
the absorption of tetracycline. Doxycycline
is rapidly and virtually completely absorbed
after oral administration and its absorption
is not affected by presence of food or milk.

The tetracyclines are widely distributed
in the body and diffuse into various body
fluids.

Adverse Effects

Because of virtually complete absorption
of doxycycline and minocycline side effects
pertaining to the lower bowel, particularly

diarrhoea have been infrequent. The

following side effects have been observed

with the use of tetracycline including

doxycycline.

Anorexia, nausea, vomiting, diarrhoea,

glossitis, dysphagia, maculopapular and

erythematous rashes and photosensitivity;

hypersensitivity reactions including

urticaria, angioneurotic edema, anaphylaxis,

anaphylactoid reactions. They also cause

discoloration of deciduous teeth.

Therapeutic Use

1. Orodental infection caused by mixed
   aerobic, anaerobic bacteria including
   Vincent’s infection caused by Fusobac-
   terium. Tetracycline also prove to be
   beneficial in peridontal inflammation
   by scavenging free radicals. Its use in
   pregnancy, lactation and in children is
   contraindicated. Its use in dentistry is
   very much restricted due to its chelat-
   ing effect on teeth and bones.


2. Respiratory tract infection: Bronchitis,
   pneumonia and other lower respiratory
   tract infections due to susceptible strains
   of Strep. pneumoniae, H. influenzae, K.
   pneumoniae and other organisms
   including Mycoplasma pneumoniae.
   Upper respiratory tract infections
   including sinusitis, otitis, mastoiditis.


3. Urinary tract infection: Caused by
   susceptible strains of Klebsiella sp.,
   Enterobacter sp., Strep. faecalis and other
   organisms.


4. Sexually transmitted diseases:
   Uncomplicated urethral, endocervical
   and rectal infections. Non gonococcal
   urethritis (NGU) caused by Ureaplasma
   urealyticum, chancroid caused by H.