Penicillins Flashcards
What class of antibiotics are penicillins?
Beta-lactam antibiotics and they all have a beta lactone structural ring
Which penicillins are highly effective against gram-positive cocci like streptococcus and Staphylococcus
Penicillin G and penicillin V
Which type of staff are the anti-staphylococcal penicillins not effective against
MRSA
Are penicillins, broad or narrow spectrum antibiotics
They are broad spectrum
What is a disadvantage of prescribing penicillin?
It has a short half-life about half an hour to one hour so it must be dosed every 4 to 6 hours to maintain concentration above the MIC
What tissues do penicillins not penetrate?
Eye, prostate, non-inflamed cerebral spinal tissue
How do beta lactam penicillins work on the bacteria
It enters the bacteria via porin and binds to the penicillin binding protein, this interrupts cell synthesis and the high osmotic pressure inside the cell burst the inner or outer cell membrane and the bacteria dies.
What are the 3 beta lactamase inhibitors?
Clavulanate,sulbactam, and tazobactam
What penicillin would you prescribe for otitis media?
Amoxicillin clauvanate
What are the adverse effects of penicillin?
Allergic reaction, serum, sickness, rash, photosensitivity, neurotoxicity, encephalopathy, G.I. reactions, diarrhea, hemolytic anemia, immune mediated thrombocytopenia
How is serum sickness categorized
Fever, rash, urticaria, adenopathy, joint swelling and glomerulonephritis
What should you do if a severe reaction occurs with a penicillin drug
You should assume complete cross allergenicity to all penicillin drugs
What type of reactions are most penicillin drugs?
Immediate reactions within 2 to 30 minutes that are type one and IGE mediated. Usually presents with flushing, angioedema wheezing abdominal distress, emesis, or diarrhea and hypotension.
When are penicillin allergies considered a late reaction
After 72 hours from drug administration, they’re considered a type two through four hypersensitivity reaction
Should you skin test for penicillin allergy and a patient with delayed reaction?
No, it is a hypersensitivity reaction and not IGE dependent
How are your cardio visions associated with penicillin, allergies characterized
They will have pruritic raised red plaques that appear in one area, then resolve over a course of hours and reappear elsewhere
Patients with what type of infection often get an amoxicillin or amoxicillin rash
Epstein-Barr virus infection
How should you treat a mild penicillin allergy?
Administer diphenhydramine for itching and skin rash
How should you treat a serious penicillin allergy?
Epinephrine, respiratory support and cortical steroids
What class of drugs can potentiate an allergic reaction to penicillin?
Beta blockers
What type of drugs decrease the action of penicillin
Tetracycline and macrolides
What two types of drugs does penicillin decrease the effectiveness of
Oral contraceptives and atenolol
What laboratory test can be affected by large penicillin doses
PT
The penicillins act by:
Interfering with bacterial cell wall synthesis
What are the three ways bacteria can become resistant to penicillins?
It’s permeability barrier, alteration in target PBP, and inactivation by beta lactamases
Are penicillin safe to use during lactation
Yes, it is a category B drug
What class of penicillins are effective against urinary and G.I. pathogens
Amino penicillins
