Pharmacology for Dentistry

Beta Lactam Antibiotics 319

cellulitis, necrorotizing ulcerative

gingivitis etc. But due to penicillin

resistance, its use in dentistry is

restricted.

• Streptococcal infections: Pharyngitis,
  rheumatic fever, otitis media and even
  for subacute bacterial endocarditis.


• Staphylococcal infections: Penicillinase
  resistant penicillin can be used.


• Meningococcal infections: Meningitis
  & other infections caused by meningo-
  cocci.


• Pneumococcal infections: Pneumonia
  and meningitis.


• Gonococcal infection: Procaine
  penicillin along with probenecid can be
  used.


• Sexually transmitted diseases:
  Penicillin is a drug of choice in the
  treatment of syphilis.


• In the treatment of actinomycosis and
  anthrax.


• In the treatment of diphtheria, tetanus
  and gas gangrene.


• Penicillins are also used in the
  prophylaxis of rheumatic fever,
  sexually transmitted diseases e.g.
  gonorrhoea and syphilis and bacterial
  endocarditis.

SEMISYNTHETIC PENICILLINS

Semisynthetic penicillins are produced by
combining the specific side chains in place
of benzyl side chain. They have been
produced to overcome the shortcomings of
benzyl penicillin like poor bioavailability,
susceptibility to penicillinase and narrow
spectrum of activity.

PHENOXYMETHYL PENICILLIN

It has an antibacterial spectrum similar

to benzyl penicillin but is less active. It is

gastric acid stable and effective on oral

administration.

Adverse effects include urticaria, fever,

rashes, angioedema, anaphylaxis, haemolytic

anemia, neutropenia, thrombocytopenia,

coagulation disorders, diarrhoea etc.

It is used in tonsillitis, otitis media,

erysipelas, prophylaxis of rheumatic fever

and pneumococcal infections.

PENICILLINASE RESISTANT PENICILLIN

It is resistant to degradation by penicillinase.

Mainly it exhibits activity against gram

positive microorganisms and is useful

against penicillinase producing Staph.

aureus.

CLOXACILLIN

It has an isoxzalyl side chain and has

weaker antibacterial activity than benzyl

penicillin. It is absorbed after oral

administration partially and elimination

occurs mainly by kidney and partly by liver.

It is devoid of any serious side effect but can

cause hypersensitivity reaction in some

patients.

Other analogs of cloxacillin are

dicloxacillin and flucloxacillin. They are

relatively less protein bound, however,

dicloxacillin gives approximately double the

blood level than cloxacillin.

BROAD SPECTRUM PENICILLINS

They have broad antibacterial spectrum and

are effective against both gram positive and