Antibiotics - Clindamycin/Tetracycline/Chloramphenicol

Question 1

Clindamycin mechanism of action

Answer 1

50S inhibitor

similar to macrolides

Question 2

Clindamycin clinical use

Answer 2

aerobic G+ (staph/strep) & anaerobic G- (Bacteroides/Fusobacterium)
Ex: S. Aureus bone infections; pen for lung abscesses; MRSA; IV for Toxo in AIDS

Question 3

Clindamycin danger

Answer 3

C. diff

Question 4

Clindamycin dosage

Answer 4

oral suspensions and IV (clindamycin phosphate) and topical

Question 5

Clindamycin metabolism

Answer 5

P450s into 1) sulfoxidation 2) N-demthylation

metabolites inactive

Question 6

Clindamycin pharmacokinetics

Answer 6

90% absorption orally; t1/2 = 1.5-5h; good CNS penetration (toxo)

Question 7

Clindamycin adverse effects

Answer 7

diarrhea, C.diff, nasuea, vomiting, cramps, rash

Question 8

If you get C.diff with clindamycin

Answer 8

switch to metro or vanco

Question 9

Tetracycline history tidbit

Answer 9

in mummies from beer production

Question 10

Tetracycline and metals

Answer 10

chelation with Ca/Al/Cu/Mg

Question 11

Tetracycline administration route

Answer 11

still oral despite chelation

Question 12

Tetracycline warnings

Answer 12

discolors developing teeth in kids

don’t inject w/o EDTA as it hurts when chelated w/ Ca2+

Question 13

Tetracycline epimerization

Answer 13

forms epitetracycline (inactive) 
happens with old solutions and pH

Question 14

Tetracycline dehydration

Answer 14

due to C-6 hydroxyl group
forms 4-epianhydrotetracycline (inactive and TOXIC)
Fanconi-like syndrome

Question 15

Why are minocycline and doxycycline safer

Answer 15

do not form 4-epianhydrotetracycline so no risk of toxicity (Fanconi-like syndrome) - lack the C-6 OH group
90-100% oral F

Question 16

Tetracycline mechanism of action

Answer 16

30S inhibitor; blocks A site attachment; do not overlap with macrolide binding
can block protein synthesis in host but no uptake mechanism
blocks in 6x different locations

Question 17

Tetracycline therapeutic use

Answer 17

broad-spectrum
acne; chlamydia; rickettsia; brucellosis; spriochetes
anthrax/plague/tuleramia/Legionnaire’s

Question 18

which tetracyclines absorption lowered 50% by food/milk

Answer 18

tetracycline/demeclocycline/oxytetracycline

Question 19

which tetracyclines have no toxicity

Answer 19

minocycline and doxycycline

Question 20

doxycycline from

Answer 20

oxytetracycline

Question 21

minocycline from

Answer 21

demeclycycline

Question 22

Best tetracycline half-life and how long

Answer 22

doxycline

18-22hr