Drugs for Bacterial Pulm Infections Flashcards
(34 cards)
What is the MOA of tetracycline class drugs?
inhibition of protein synthesis by REVERSILBE binding of 30S ribosome. Bacteriostatic
What do the side groups of penicillins do?
provide different chemical, pharmacological and antimicrobial properties
What is clavulanate?
a B-lactamase inhibitor often given with penicillin or other B lactams to overcome resistance
What are the natural penicillins and what are they effective against?
penicillin G (parenteral) and penicillin V (oral).
effective against gram+ cocci (S. pneumo).
Ineffective against most gram- and staph aureus strains
What are the aminopenicillins and what are they effective against?
ampicillin and amoxicilin
effective against gram+ AND gram- (like heamophilus Influenza and E. Coli)
What is agumentin? What is it effective against?
Augmentin is amoxicillin (an aminopenicillin) combined with clavulanic acid (a B-lactamase inhibitor).
The clavulanic acid extends the spectrum of penicillin to include MSSA (staph aureus) and anaerobes
Are Pen V drugs resistant to acid? Should they be taken with or without food?
Penicillin V drugs are resistant to acid destruction, but they should be given 1 to 2 hours AFTER meals to avoid high acid levels and improve absorption.
How are penicillins metabolized and excreted?
hepatic enzyme metabolism and 90% renal tubular excretion.
What is the most common adverse effect of penicillins?
Allergic reactions. Potentially serious.
AAD (antibiotic associated diarrhea) also common though it is more prevalent in broad spectrum antibiotics.
Can cause hypokalemia becuase K+ is lost in urine during drug excretion.
What will modifications at position 7(R1) of the B-lactam ring in cephalosporins do? Modifications of the 3(R2) position of the dihydrothiazine ring?
7(R1) alters the antibacterial activity.
3(R2) alters the metabolism and pharmacokinetic properties
Describe the differences between 1st and 3rd generation cephalosporins?
1st –> 3rd gen have 4 differences:
- More Gram- action
- Less Gram+ action
- increased B-lactamase resistance
- Increased CSF permeability
What are the 3rd gen cephalosporins? What bugs are they effective against?
cefotaxime, ceftriaxone, ceftazadime, and cefixime.
Effective against H. influenza and pseudomonas(ceftazadime only)
Are cephalosporins effective against enterococci?
NO. not at all
What allows imipenem and other carbapenems to be effective against gram-?
small hydroxyethyl side chain grants high effectiveness against most Gram- bacteria. They are the broadest spectrum of any B-lactam antibiotic
What must imipenem be administered with? Why?
MUST be given with cilastatin to inhibit dehydropeptidase to prevent drug breakdown and renal toxicity
What are some of the main adverse effects of carbapenems?
same as B-lactams (allergies and AAD).
More concerning - seizures and CNS toxicity at high doses.
How are meropenem and eratpenem different from imipenem?
Cilastatin is not necessary with meropenem and ertapenem because they do not break down and cause renal toxicity like imipenem does. They are also more active against gram- bacilli and have fewer side effects.
What is the proper treatment for acinetobacter? What is unique about acinetobacter?
acinetobacter is inherently resistant to most antibiotics. It should be treated with a combination of carbapaenem with aminoglycoside (amikacin).
What is the mechanism of macrolide drugs? What are examples of macrolides?
Reversibly binds to 50S ribosomal subunit to inhibit protein synthesis. Bacteriostatic. Erythromycin, clarithromycin, azithromycin.
What confers resistance to macrolides?
MLSb (macrolide-lincosamidepstreptogramin B) phenotype is conferred by Erm genes.
How is erythromycin excreted?
primarily in bile and feces
What are the primary uses of erythromycin?
used in patients allergic to penicillins. Good for Gram+ and Gram- infections (legionnaire’s, mycoplasma, chlamydia)
What are some of the adverse effects of erythromycin?
inhibits P450. QT prolongation, cholestatic hepatitis and transient deafness.
What benefits/disadvantages does clarithromycin have over erythro? Azithromycin?
Clarithromycin is more acid-stable and absorption increases with food. (clari = in the clear for food)
Azithromycin is also more acid-stable but its absorption is DECREASED with food.
Azithro has no CYP inhibition (major advantage)
