Tetracyclin and glycylcyclines

Question 1

What are tetracyclins?!
Cidic or static?
Broad or short spectrum?

Answer 1

PROTEIN SYNTHESIS INHIBITOR ANTIBIOTICS
Bacteriostatic drugs
Broadspectrum

Question 2

Which tetracyclin drugs do you know?

Half life is different for the drugs!

Answer 2

Shoft acting: tetracycline, oxytetracycline
Medium acting methacycline
Long acting (36~ hours)- doxycycline).

chlorotetracycline, doxycycline, minocycline

Question 3

Mechanism

Answer 3

bind reversibly to 30S subunit of the bacterial ribosomes, prevent the binding of the incoming charged tRNA,
inhibit protein synthesis in bacteria.

Question 4

specturm

Answer 4

Broad spectrum with good activity versus 
1) Helicobacter.
2) Vibrio infections (cholera).
3) Brucellosis.
4) Francisella tularensis
5) Atypical bacteria:
Rickettsiae, 
Chlamydia
Spirochetes (all 3)
Mycoplasma pneumoniae.

Gram + Anerob and anerobic = yes
Gram - anerob and anarob= yes
Atypica= yes

Other infections of such: bronchitis, pneumonia, UTI, and more.

Question 5

resistance to tetracyclins

Answer 5

efflux pumps by gram - bacteria

Enzymatic inactivation by bacteria and proteins that intefere with the binding of the antibiotic to the ribosome.

Question 6

kinetics of tetracyclins

Answer 6

Oral absorption mainly, tigercyclin is mainly used in the IV form.

Distribution to many organs such as kidney, gingiva, skin and more.
Does not cross BBB but does cross placenta!

Excretion is renal and liver

Question 7

Adverse effects:

Contra in…

Answer 7

1) Tooth enemal dysplasia and possible reduction in bone growth in children
2) photosensitivity (demeclocycline and doxycycline)
3) GI distress- can lead to candiasis and enterocolitis
4) vestibular dysfunction (minocycline).
5) Liver dysfunction during pregnancy at high doses (contraindicated).
6) Kidney toxicitiy.
7) hypersensivity rxns

Generally not recommended below age of 8!!!
Pregnency is contraindicated due to entry to fluid.

Question 8

what is doxycycline really good for?

Answer 8

prostatitis

Question 9

what is demeclocycline really good for?

Answer 9

used in syndrome of inappropriate secretion of ADH (SIADH; blocks ADH receptor function in collecting ducts).

Question 10

give an exmaple of a glycylcycline
What is it
Mechanism:

spectrum
Kinetics:
Admin
Adverse

Answer 10

tigecycline- a derivative of minocycline.

broad-spectrum antibiotic that acts as a protein synthesis inhibitor. It exhibits bacteriostatic activity by binding to the 30S ribosomal subunit of bacteria and thereby blocking the interaction of aminoacyl-tRNA with the A site of the ribosome.

Spectrum: (broad spectrum)

• Tetracyclin resistant bacteria
• MRSA and VRE
• Vancmycin resistant staphylococci and streptococci.
• Penicilin resistant enterococci.
• Enterobactericae.
• ATypical and legionella.

Kinetics:
IV ONLY
Elimination by liver and has a long half life (1.5 day).

Clinical indications:
skin infections,
intraabdominal infections,
usually not used in urinary infections
low concentration in urine

Adverse effects:
gi symptoms (nusea and vomit).
acute pancreatitis!! (fatal sometimes!)
elevation of liver enzymes 
more tetracyclin side effects.