Tetracyclines

Question 1

What is the MOA of Tetracyclines?

Answer 1

They bind to the 30s subunit and block tRNA from attaching to the ribosome. Without tRNA, the ribosome cannot add new amino acids to the growing protein chain, effectively stopping the bacteria from growing–> Bacteriostatic.

Question 2

What is the SOA of Tetracyclines?

Answer 2

Broad spectrum; Gram (+) and (-), Atypicals

Question 3

What is the group 1 tetracyclines and what are important facts to note?

Answer 3

Tetracycline

Do not take with food, dairy products, calcium, magnesium, or iron.

Binds to tissues undergoing calcification such as bones and teeth. It accumulates in areas where calcium is high and loses their antimicrobial properties.

Question 4

What are the group 2 tetracyclines and what are important notes?

Answer 4

Doxycycline and Minocycline

Doxycycline:
Preferred for patients with renal failure because it is excreted in the bile.
DOC in Ricketts, Lyme Disease, and prostatitis by chlamydia

Minocycline:
Penetrates deeply into tissues such as saliva, tears, and the CNS.
Used in Meningococcal carrier state.

Question 5

What is the third group of tetracyclines and what are important things to note here?

Answer 5

Tigecycline:

Only administered IV. Used against resistant bacteria such as MRSA, VRE faecium and gram (-) aerobes.

Question 6

What are side effects of Tetracyclines?

Answer 6

Tooth enamel dysplasia causing discoloration of teeth and can cause tooth/bone development issues in children.
Photosensitivity (sunburn)
GI distress
Hepatotoxicity
Nephrotoxicity
Pseudotumor Cerebri

Question 7

Who are contraindicated from taking Tetracyclines?

Answer 7

Pregnant women and children < 8 years of age