Term
| Are tetracyclines bacteriacidal or bacteriastatic? |
|
Definition
|
|
Term
| What is the mechanism of action of tetracyclines and glycyclines? |
|
Definition
| protein synthesis inhibitors: reversible binding at the 30S ribosomal subunit |
|
|
Term
| What spectrum of activity is tetracycline good against? |
|
Definition
atypicals
rickettsia
spirochetes
Plasmodium (malaria) |
|
|
Term
| What spectrum does tetracycline have moderate activity against? |
|
Definition
Staph (both MSSA and MRSA): generally community MRSA
S. pneumoniae |
|
|
Term
| What spectrum does tetracycline have poor activity against? |
|
Definition
many gram - rods (ex. enterobacteriaceae, pseudomonas)
anaerobes
enterococci |
|
|
Term
| What are bacterial mechanisms of resistance to tetracyclines? |
|
Definition
| efflux (doesn't effect doxycycline or minocycline as much as tetracycline) |
|
|
Term
| What are the three major tetracycline compounds? |
|
Definition
tetracycline
doxycycline
minocycline |
|
|
Term
| What is the bioavailability of tetracycline? |
|
Definition
|
|
Term
| What is the bioavailability of doxycycline? |
|
Definition
|
|
Term
| What is the bioavailability of minocycline? |
|
Definition
|
|
Term
| What decreases the absorption of tetracycline? |
|
Definition
|
|
Term
| Why should a patient avoid eating food/drinking milk while taking tetracycline? |
|
Definition
| tetracycline gets bound (chelated) by divalent cations and becomes unavailable for absorption |
|
|
Term
| What should you tell a patient who is taking tetracycline? |
|
Definition
| avoid calcium supplements, iron supplements, antacids |
|
|
Term
| Is tetracycline distributed well? |
|
Definition
| Yes, it has excellent tissue penetration. |
|
|
Term
| hepatic metabolism of tetracycline |
|
Definition
|
|
Term
| hepatic metabolism of doxycycline |
|
Definition
|
|
Term
| hepatic metabolism of minocycline |
|
Definition
|
|
Term
| elimination of tetracycline |
|
Definition
60% unchanged in urine
significant bile/fecal elimination |
|
|
Term
| elimination of doxycycline |
|
Definition
20-30% in urine
remainder in bile/feces |
|
|
Term
| elimination of minocycline |
|
Definition
approximately 10% in urine
remainder in bile/feces |
|
|
Term
| What is the problem with a drug being excreted fecally? |
|
Definition
| There is more exposure of enterobacteriaceae to drug which can cause "collateral" damage by increasing resistance of the bacteria in the GI tract |
|
|
Term
| What is the half-life and dosing of tetracycline? |
|
Definition
approximately 6 hours
must give drug 3-4x a day |
|
|
Term
| What is the half life and dosing of doxycycline? |
|
Definition
15-24 hours
give drug 2x/day |
|
|
Term
| What is the half-life and dosing of minocycline? |
|
Definition
half-life 11-22
give drug 2x/day |
|
|
Term
| What are the adverse effects of tetracycline? |
|
Definition
gastrointestinal (N/V, diarrhea)
photosensitivity
hepatitis
hypersensitivity
tooth discoloration
antianabolic effects |
|
|
Term
| What are the precautions for tetracyclines? |
|
Definition
pregnancy category D
cause inhibition of bone growth in fetus
do not use in pregnant or breastfeeding women
do not use in children <8 |
|
|
Term
| What are the therapeutic uses of tetracycline compounds? |
|
Definition
Rickettsial infections (Rocky Mountain spotted fever)
Lyme disease
acne
acute exacerbations of chronic bronchitis
prevention of travelers diarrhea |
|
|
Term
| What are the interactions that can take place with tetracyclines? |
|
Definition
| antacids, calcium and iron supplements all chelate with tetracycline |
|
|
Term
| What is the one glycylcycline drug? |
|
Definition
|
|
Term
| What is tigecycline a derivative of? |
|
Definition
|
|
Term
| What is the advantage of tigecycline over the tetracycline compounds? |
|
Definition
| significant increase in bacterial activity |
|
|
Term
| What dosage form does tigecycline come in? |
|
Definition
|
|
Term
| What is the mechanism of action of tigecycline? |
|
Definition
| binds to 30S ribosomal subunit to prevent protein synthesis |
|
|
Term
| What is tigecycline's gram + activity? |
|
Definition
pretty significant gram + activity
S. aureus (including MRSA)
Enterococcus species (including VRE)
S. pneumoniae |
|
|
Term
| What is tigecycline's gram - spectrum of activity? |
|
Definition
Enterobacteriaceae
Acinetobacter |
|
|
Term
| Does tigecycline have anaerobic coverage? |
|
Definition
| Yes, it has good anaerobic coverage |
|
|
Term
| What is tigecycline's most common use? |
|
Definition
| intra-abdominal infections |
|
|
Term
| What is tigecycline's "weak spot"? |
|
Definition
| poor Pseudomonas activity--this hinders its empiric use |
|
|
Term
| Does tigecycline have good tissue penetration? |
|
Definition
| Yes, it is also slowly released in tissues. However, it does not have good blood concentrations. |
|
|
Term
| How is tigecycline eliminated? |
|
Definition
|
|
Term
| What is the average half-life of tigecycline and how is it dosed? |
|
Definition
| 36 hours, drug given 2x/day |
|
|
Term
| Why is tigecycline dosed 2x/day instead of 1x/day? |
|
Definition
| there were adverse affects with the once a day higher dose than with the lower twice a day dosing |
|
|
Term
| What is tigecycline's significant adverse effect? |
|
Definition
| nausea and vomiting (approx. 30%) |
|
|
Term
| What is an advantage that tigecycline has over the other tetracycline compounds? |
|
Definition
| most tetracycline resistance mechanisms do not affect tigecycline |
|
|
Term
| What are tigecycline's FDA approved uses? |
|
Definition
complicated skin and soft tissue infections
intra-abdominal infections
(also CAP, but not used for this) |
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