Cushman Lecture 2

Question 1

Cephamycins

Answer 1

• 7a-methoxyl group – increases stability vs B-lactamases
• cefotetan - parenteral – broad activity spectrum
• releases N-methylthiotetrazole, which can cause hypoprothrombinemia and cause rxn to ethanol (don’t drink alcohol with this medication)
• generally stable to B-lactamases

Question 2

Carbapenems

Answer 2

• methylene group (instead of sulfur like in penicillins) makes drug more reactive bc methylene is smaller so more steric strain so more reactive — parenteral
• imipenem – parenteral product
• reacts with PBPs and inhibits B-lactamases
• hydrolyzed by renal dehydropeptidase-1 (so given with cliostatin)
• broad gram + and - spectrum, so reserved
• treats serious infections like gut, GU tract, bone, skin, and endocardium

Question 3

Monobactams

Answer 3

• activity focused on gram - bacteria (severe infections)
• treats penicillin resistant organisms acquired in hospitals
• Aztreonam disodium – parenteral
• sulfamic acid activates B-lactam ring toward chemical hydrolysis and to react with PBPs
• oxime either makes it resistant to hydrolysis by B-lactamases

Question 4

Glycopeptides (vancomycin)

Answer 4

• ## inhibits cell wall biosynthesis in gram + so crosslinking is inhibited