Tetracyclines

Question 1

What are the Tetracyclines? (Main ones)

Answer 1

• Doxycycline
• Minocycline
• Tigecycline (Tygacil)

Question 2

How do the Tetracyclines work?

Answer 2

In the 30S particle of the bacteria’s ribosome, they prevent binding and affect protein synthesis.

Question 3

What are the Oral absorption characteristics of the Tetracyclines?

Answer 3

• Tetracycline/demeclocycline: 60-70%
• Doxycycline/minocycline: 95-100% (Good for IV to PO)
• Tigecycline- poor

Question 4

What are the Distribution characteristics of the Tetracyclines?

Answer 4

Wide tissue distribution

Question 5

What are the Excretion characteristics of the Tetracyclines?

Answer 5

• Renal and liver

- Nonrenal: doxycycline and tigecycline

Question 6

What are the Duration characteristics of the Tetracyclines?

Answer 6

• Short: tetracycline (4X a day)
• Intermediate: demeclocycline (2x a day)
• Long-acting: doxycycline, minocycline, tigecycline (1-2x a day)

Question 7

What does doxycycline and minocycline kill?

Answer 7

susceptible Rickettsia (Q fever).

Chlamydia, Chlamydophila, and Mycoplasma, uncomplicated Neisseria gonorrhoeae (alternative agent), Listeria, Actinomyces israelii, and Clostridium infections in penicillin-allergic patients, Bacillus anthracis, Borrelia recurrentis, Ureaplasma urealyticum, Haemophilus ducreyi, Yersinia pestis, Francisella tularensis, Vibrio cholerae, Campylobacter fetus, Brucella spp, Bartonella bacilliformis, and Klebsiella granulomatis

Question 8

What does tetracycline (general) kill?

Answer 8

gram-positive and gram-negative organisms; also infections due to Mycoplasma, Chlamydia, and Rickettsia

Question 9

What does tigecycline (IV only) kill?

Answer 9

Complicated skin and skin structure infections caused by susceptible organisms, including methicillin-resistant Staphylococcus aureus and vancomycin-sensitive Enterococcus faecalis; complicated intra-abdominal infections; community-acquired pneumonia

 - Haemophilus influenzae
 - Legionella pneumophilia
 - Streptococcus pneumoniae

*For Infectious disease consults!

Question 10

What are the types of resistance to Tetracyclines?

Answer 10

• Impaired influx/increased efflux
• Interference with ribosomal binding by the tetracyclines
• Enzymatic inactivation

Question 11

What are the side effects of the Tetracyclines?

Answer 11

• Gastrointestinal
• Hepatic
• Photosensitivity
• Central nervous system: Headache, nausea
• Bony structures
• Fanconi syndrome: nausea/vomiting due to using outdated drug

Question 12

What is Doxycycline used for?

Answer 12

• Rickettsial infections
• Syphilis (alternative)
• Chlamydia
• Community-acquired pneumonia
• Anthrax
• Q fever
• Lyme disease
• Severe acne

Question 13

What is Minocycline used for?

Answer 13

• Anthrax
• Moderate to severe acne
• Meningococcal carrier state
• Rickettsial infections
• Gonorrhea and non-gonococcal urethritis\
• Intestinal amebiasis

Question 14

What is Tigecycline used for?

Answer 14

• Complicated skin and skin structure infection
• Complicated intra-abdominal infection
• Community-acquired pneumonia

Question 15

What is the prescription for Doxycycline?

Answer 15

100 mg
every twelve (12) hours
IV or oral

Good for bronchitis, Community-acquired pneumonia, Lyme disease

Question 16

What is the prescription for Tygacil™ (Tigecycline)?

Answer 16

100 mg IVPB loading X 1 then
50 mg IVPB
twice a day

Adjust does for liver –> 25 mg IVPB 2x a day