Drugs to Treat Bacterial Infections Flashcards
How do B-lactamases work and what bacteria are they most commonly found in?
Breaking of the carbon-nitrogen bond in the beta lactam ring structure inactivates penicillins AB capability. Commonly seen in Staph aureus and most of the Gram negative organisms
What is a synergistic response
When two drugs have mechanisms that complement each other.
Use of Carbapenems
Severe infections with gram negative bacilli. They work well with gram negatives because they have a small hydroxyethyl side group that allows them to move through the outer membranes of gram negative organisms.
Imipenem is contraindicated in who?
Pts predisposed to seizures
What are all of the drugs in the Carbapenem class that we need to know
Imipenem, Meropenem, Ertapenem
What must you give Imipenem with to prevent its hydrolysis by dipeptidase in the proximal renal tubule
Cilistatin
Must you give Cilistatin with Meropenem and Ertapenem>
No
What combination of drugs is used to treat Acinetobacter
Carbapenem and Amikacin
Name the two macrolides we need to know
Erythromycin and Clarithromycin
When do you use Erythromycin
When Penicillin doesnt work on a gram positive organism
Are Erythromycin and Clarithromycin static or cidal
static
How do Macrolides work>
Bind ribosomal 50S subunit and prevent protein synthesis.
What is the significance of the MLSb phenotype
This phenotype of organism may acquire resistance to the Macrolides because it contains methylases that modify the macrolide binding site on the ribosome.
What dont you give macrolides with
Other CYP3A inhibitors because they can cause QT prolongation.
What is the difference between clarithromycin and erythromycin
Clarithromycin is more stable and absorption increases with food (opposite of erythromycin)
