Penicillins- drugs, indications, adverse effects, drug interactions,
contraindications, patient teaching, cross-sensitivity.
Beta-Lactam: PCN
Pharmacodynamics
- Inhibit the biosynthesis of peptidoglycan bacterial cel
...
Penicillins- drugs, indications, adverse effects, drug interactions,
contraindications, patient teaching, cross-sensitivity.
Beta-Lactam: PCN
Pharmacodynamics
- Inhibit the biosynthesis of peptidoglycan bacterial cell wall
- Sensitivity
- Natural PCNs: Streptococcus, some Enterococcus strains, some
non–penicillinase-producing Staphylococcus
- Aminopenicillins: greater activity against gram-negative bacteria because of
enhanced ability to penetrate the outer-membrane organisms
- Used for gram-negative urinary and gastrointestinal (GI) pathogens – Escherichia
coli, Proteus mirabilis, Salmonella, some Shigella species, and Enterococcus
faecalis; active against the common gram-negative respiratory pathogens
Moraxella catarrhalis (and Haemophilus influenzae type B)
- Combination with beta-lactamase inhibitors to broaden their spectrum: clavulanate,
sulbactam, tazobactam
Pharmacokinetics
- Well-absorbed from GI tract, but several are unstable in acid: dicloxacillin and amoxicillin
better absorbed than ampicillin
- Bound to proteins with good distribution to most tissues
- Small amount is metabolized; most are excreted as unchanged drug in urine.
- Probenecid prolongs half-life and increases risk for toxicity.
ADR
- May cause serious immediate allergic reactions
- Reactions occur within 2 to 30 minutes of administration.
- Patients may be given desensitization therapy.
- Rash: maculopapular rash occurs 9% of time, is not allergic in origin, and appears 7 to
10 days into treatment.
- GI: diarrhea, nausea/vomiting (n/v); addition of clavulanate increases risk of diarrhea
- Fungal overgrowth
- Clostridium difficile colitis
- Most are pregnancy category B
Clinical use and dosing
- Commonly prescribed for infections seen in primary care
- Amoxicillin: first-line therapy for acute otitis media (AOM) and
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