Penicillins – Infectious Diseases

Penicillins – Infectious Diseases

Classify Penicillins According To Their Antibacterial Spectrum. Mention The Therapeutic Uses And Adverse Effects Of Penicillin­G.
Answer:

Classification Of Penicillin According To Its Antibacterial SpectrumHemophilia and Blood Coagulation Treatment

1. Narrow spectrum: Penicillin G
2. Extended-spectrum penicillin or semi-synthetic penicillin

• Acid-resistant alternative to penicillin G: Penicillin V
• Penicillinase-resistant penicillin, i.e., methicillin, oxacillin, cloxacillin
• Extended-spectrum antibiotics:
  • Aminopenicillin: Ampicillin, amoxicillin
  • Carboxypenicillin: Carbenicillin, ticarcillin
  • Ureidopenicillin: Piperacillin, mezlocillin.

Therapeutic Uses Of Penicillin G

• In Dental infections: Parenteral penicillin G remains effective in the majority of common infections encountered in dentistry, particularly those arising as a sequela of carious lesions and are caused by both aerobic and anaerobic bacteria such as Streptococci, Peptostreptococci, Eubacterium, Prevotella, Porphyromonas, and Fusobacterium.
  • At ordinary doses, it can be used for periodontal abscess, periapical abscess, pericoronitis, acute suppurative pulpitis, ANUG, oral cellulitis, etc. Penicillin G can also be employed prophylactically to cover dental procedures in predisposed patients.
• General medicinal uses: Other medical conditions treated with Penicillin G are:
  • Streptococcal infections: Pharyngitis, tonsillitis, otitis media, scarlet fever, rheumatic fever, etc. For bacterial endocarditis caused by viridian streptococci, high doses are required in combination with gentamicin.
  • Pneumococcal infections (pneumonia, meningitis) only if the infecting strain is found to be sensitive to penicillin G.
  • Meningococcal meningitis and other infections.
  • Gonorrhea is caused by non-penicillinase-producing N. gonorrhea, etc. that are still sensitive to Penicillin G.
  • Syphilis: Benzathine penicillin is the drug of choice for all stages because T. pallidum has not developed penicillin resistance.
  • Diphtheria, tetanus, and other rare infections like gas gangrene, anthrax, and actinomycosis.

Adverse Effects Of Penicillin G

Local Irritancy And Direct Toxicity

• Pain at the IM injection site, nausea on oral ingestion, and thrombophlebitis of the injected vein are dose-related expressions of irritancy.
• Toxicity to the brain may be manifested as mental confusion, muscular twitching, convulsions, and coma.

Hypersensitivity

• These reactions are the major problem in the use of penicillins. Individuals with an allergic diathesis are more prone to develop penicillin reactions.
• Frequent manifestations of penicillin allergy are rash, itching, urticaria, and fever.
• Wheezing, angioneurotic edema, serum sickness, and exfoliative dermatitis are less common.
• Anaphylaxis is rare but may be fatal.

Superinfections

They are rare with penicillin G because of their narrow spectrum.

Jarisch-Herxheimer Reaction

Penicillin injected in syphilitic patients mostly secondary syphilis may produce shivering, fever, myalgia, exacerbation of lesions, and vascular collapse.