Penicillins are the beta lactam antibiotics used to treat various conditions like pharyngitis, tonsilitis, endocarditis, diphtheria, anthrax and syphilis.

1. By Dr. Dinesh Kumar G
Pharm. D

18. ANTIBIOTICS: PENICILLINS
DRUG NAME penicillin G, penicillin V amoxicillin, ampicillin
dicloxacillin, nafcillin,
oxacillin
piperacillin-tazobactam
CLASS Basic Penicillins
Broad-Spectrum
Penicillins
(Aminopenicillins)
Penicillinase-Resistant
Penicillins
(Antistaphylococcal
Penicillins)
Extended-Spectrum
Penicillins
(Antipseudomonal
Penicillins)
MOA Inhibition of the enzyme in cell wall synthesis; bactericidal effect
INDICATIONS
•Upper respiratory infections
•Otitis media
•Pneumonia
•Rheumatic fever
•Skin and soft-tissue infections
•Gonorrhea and syphilis
•Treatment of infections:
• skin
• respiratory
• GI and GU
•Amoxicillin: gonorrhea
•Ampicillin: meningitis,
endocarditis, septicemia
•Infections caused by
Penicillin G–resistant
Staphylococcus aureus
Infections caused by
Pseudomonas aeruginosa.
ROA
•Penicillin G: IM, IV
•Penicillin G benzathine: IM
•Penicillin V: PO
•Amoxicillin: PO
•Ampicillin: PO, IM, IV
•Dicloxacillin: PO
•Nafcillin, Oxacillin: IM, IV
•IV
SIDE EFFECTS
•Seizures
•Nausea, vomiting, diarrhea
•Superinfections (e.g., CDI, candidiasis, vaginitis), Urticaria, pruritus, anaphylaxis, Stevens-Johnson syndrome
•Interstitial nephritis, renal tubular damage
•Penicillin G: Local pain at injection site, accidental intra-arterial injection or near a major peripheral nerve can cause
severe neurovascular damage and tissue necrosis
•Amoxicillin: Eosinophilia, anemia thrombocytopenia

19. ANTIBIOTICS: PENICILLINS
CONTRAINDICATIONS
AND CAUTIONS
•Contraindications: Hypersensitivity to penicillins.
Precautions: Hypersensitivity to cephalosporins and carbapenems, Pregnancy, breastfeeding
•Severe renal disease
•Boxed Warning: Penicillin G benzathine: IV use
Drug interactions:
Probenecid increases penicillin effect
•Tetracyclines decrease the effect of penicillins
•Penicillins increase effect of methotrexate
•Penicillins decrease the effect of oral contraceptives
•Broad-Spectrum Penicillins: Allopurinol increases risk of rash
•Penicillinase-resistant penicillins:
•Decrease effect of live virus vaccines, do not use together
•Food, carbonated drinks, and citrus fruit juices decrease absorption of penicillinase-resistant
penicillins

20. ANTIBIOTICS: PENICILLINS
ASSESSMENT AND
MONITORING
Vital signs
•Current signs and symptoms
•Laboratory test results: CBC, renal and hepatic function, VDRL
•Diagnostic test results: lumbar puncture
Administration
Ensure adequate hydration
•Patent IV and Indwelling urinary catheter
Insertion site; rotate regularly
•Side effects Hypersensitivity, Superinfection, Renal damage
•Evaluate: resolution of the infection; absence of symptoms
Client education
Purpose of the medication: treats the infection causing their symptoms
•Administered intravenously over two weeks
•Side effects
• Report pain or discomfort at the insertion site
• Abdominal pain