Penicillin
PENICILLIN
MOA:
- Are bactericidal antibiotics.
- Bacterial cell wall synthesis completely depends on transpeptidase enzyme.
- Penicillin inhibits bacterial cell wall synthesis by blocking transpeptidase after binding to penicillin-binding protein (PBP).
CLASSIFICATION:
SOURCE
- NATURAL(Endrin plant Penicillin)
- Penicillin-G
- Penicillin-V
SEMI-SYNTHETIC
- Oxacillin
- Cloxacillin
- Dicloxacillin
- Methicillin
- Nafcillin
- Ampicillin
- Amoxycillin
- Carbenicillin
- Piperacillin
ROUTE OF ADMINISTRATION:
- ORAL
- Ampicillin
- Amoxycillin
- Penicillin-V
- Oxacillin
- Cloxacillin
- Dicloxacillin
PARENTERAL Ticarcillin
- Penicillin-G
- Methicillin
- Nafcillin
- Carbenicillin
- Piperacillin(anti-pseudomonal drug)
- (Methicillin is Acid Labile penicillin)
SPECTRUM OF ACTIVITY:
NARROW SPECTRUM
- Methicillin
- Oxacillin
- Nafcillin
- Dicloxacillin
BROAD SPECTRUM
- Ampicillin
- Amoxycillin
INTERMEDIATE SPECTRUM
- Penicillin-G
- Penicillin-V
EXTENDED SPECTRUM
- Carbenicillin
- Ticarcillin
- Piperacillin
- Mezlocillin
RESISTANCE TO ENZYME:
RESISTANCE TO β-LACTAMASE
- Methicillin
- Nafcillin
- Oxacillin
- Cloxacillin
- Dicloxacillin
NON- RESISTANCE TO β-LACTAMASE
- Penicillin-G
- Penicillin-V
- Ampicillin
- Amoxycillin
- Carbenicillin
RESISTANCE TO ACIDS:
ACID STABLE
- Penicillin-V
- Ampicillin
- Amoxycillin
- Oxacillin
- Cloxacillin
- Dicloxacillin
ACID UNSTABLE
- Penicillin-G
- Methicillin
- Nafcillin
- Carbenicillin
- Piperacillin
- Ticarcillin
USES:
Streptococcal Infections:
- Pharyngitis,
- Otitis Media,
- Scarlet Fever
- Rheumatic Fever (1.2 MU every 4 weeks of benzathine penicillin)
- Subacute Bacterial Endocarditis
- Treatment of spreading streptococcal cellulitis
Pneumococcal Infections:
- Lobar Pneumonia.
- Antipseudomonal penicillins includes carboxypenicillin & ureidopenicillins.
Meningococcal Infections:
- Meningitis
Gonococcal Infections:
- Ophthalmia Neonatorum
- Syphilis(2.4 MU single i.m. of benzylpenicillin )Treatment for clostridial myonecrosis
Leptospirosis:
- Presence of fever, jaundice and renal failure in a sewage worker (contact with rat urine) suggests a diagnosis of Wen syndrome or Icterohemorrhageic fever caused by leptospirae.
- Penicillin G (intravenously) is recommended agent.
- Diphtheria
- Tetanus
- Anthrax
- Quinsy
- Treatment of contaminated wound in Gas Gangrene
- Drug of choice for Treponema Pallidum
- Actinomycosis: For thoracic actinomycosis
- Enterococcus faecalis: When isolated in blood, requires synergistic activity of penicillin plus an aminoglycoside for appropriate therapy.
- Rat bite fever
- Prophylaxis
- Rheumatic Fever
- Bacterial Endocarditis
- Agranulocytosis
ADVERSE EFFECT:
Hypersensitivity-
- rash, itching, urticaria, fever
- wheezing, angioneurotic edema, serum sickness, exfoliative dermatitis (less common)
- Anaphylaxis (rare, but fatal)
Superinfections
- Bowel, respiratory and cutaneous microflora can undergo changes
- Jarisch- Herxheimer Reaction
Local irritation
- Pain at injection site
- Thrombophlebitis
Neurotoxicity
- Mental confusion, muscular twitching, convulsions, coma
Bleeding
- Due to interference of platelet function
- Intrathecal PnG injections (not recommended)
- Arachnoiditis, degenerative changes in spinal cord
- Accidental IV procaine penicillin injection
- CNS stimulation, hallucinations, convulsions.
PENICILLIN RESISTANCE
Beta-lactamase (Penicillinase) Production
- Most common mechanism
- Both gram-positive & gram-negative organism produces beta-lactamase which opens beta-lactam ring inactivating antibiotic.
Altered penicillin-binding protein (PBP)
- Bacteria alters penicillin-binding protein structure, transpeptidase.
- Hence, prevents penicillin-binding site.
- Eg: In case of MRSA.
Exam Question
- Treatment of S. aureus infection with penicillin is often complicated by the production of penicillinase by S. aureus
- Carbenicillin is NON- RESISTANCE TO β-LACTAMASE
- Syphilis, Anthrax and Bacterial meningitis are therapeutic uses of penicillin G
- Antipseudomonal penicillins include the carboxypenicillin and the ureidopenicillins.
- Penicillin Binding Proteins (PBPs) are essential for cell wall synthesis
- Penicillin Binding Proteins (PBPs) act as carboxypeptidases and transpeptidases
- Alteration in PBP’s is the primary bases of resistance in MRSA
- β- Lactamase production is the most common mechanism of resistance to Penicillin
- Alteration in permeability/penetration of antibiotic causes resistance only in Gram-negative bacteria
- β-Lactamase production causes resistance in both Gram-positive and Gram-negative bacteria
- Penicillin would be LEAST effective in treating Mycoplasma pneumonia
- Enterococcus faecalis when isolated in the blood, requires the synergistic activity of penicillin plus an aminoglycoside for appropriate therapy
- Plant penicillin is Endrin
- Penicillins inhibits cell wall synthesis
- Methicillin is Acid Labile penicillin
- Penicillinase-resistant penicillin Methicillin
- The dosage of benzylpenicillin in the treatment of primary syphilis is 2.4 MU single i.m.
- Treatment for clostridial myonecrosis is Penicillins
- Penicillin is Drug of choice for Treponema Pallidum
- Penicillin is Drug of choice for thoracic actinomycosis
- Penicillin in high doses can cause convulsions
- The clinical presentation of fever, altered sensorium and purpuric rashes, is highly suggestive of meningococcal meningitis is treated with Penicillin
- TOC for penicillin-resistant gonorrhoea Ceftriaxone
- Presence of fever, jaundice and renal failure in a sewage worker (contact with rat urine) suggests a diagnosis of Wen syndrome or Icterohemorrhageic fever caused by leptospirae. Penicillin G (intravenously) is the recommended agent.
- Treatment of spreading streptococcal cellulitis is Penicillin
- Treatment of contaminated wound in Gas Gangrene is Penicillin
- Rapidly spreading infection of the external auditory canal with the involvement of the bone and presence of granulation tissue point towards malignant otitis externa treated with Penicillin
- Penicillin is used in the treatment of quinsy
- Piperacillin is an anti-pseudomonal drug of penicillin-class
- Dose and duration of benzathine penicillin for prophylaxis of rheumatic fever is 1.2 MU every 4 weeks
Don’t Forget to Solve all the previous Year Question asked on Penicillin
