Sandeep Mewada Pharmacology & Medicinal Chemistry

1. Tetracycline
• Tetracycline, is an antibiotic
used to treat a number of
infections.
• This includes acne, cholera,
brucellosis, plague, malaria,
and syphilis.
• It is taken by mouth.

2. Tetracycline antibiotic.

3. Common side effects include
•vomiting,
•diarrhea,
•rash,
•and loss of appetite.

4. Other side effects include
• Poor tooth development if used by
children less than eight years of age,
kidney problems, and sunburning easily.
• Use during pregnancy may harm the
baby.
• Tetracycline is in the tetracyclines family
of medications.
• It works by blocking the ability of
bacteria to make proteins.

5. Medical uses
• It is first-line therapy for Rocky Mountain
spotted fever (Rickettsia),
• Lyme disease (B. burgdorferi),
• Q fever (Coxiella),
• psittacosis,
• lymphogranuloma venereum
(Chlamydia), and Mycoplasma
pneumoniae and to eradicate nasal
carriage of meningococci.

6. Spectrum of bacterial susceptibility
• Tetracyclines have a broad spectrum
of antibiotic action.
• MIC susceptibility data for a few
medically significant
microorganisms:
• Escherichia coli: 1 μg/mL — >128
μg/mL
• Shigella spp.: 1 μg/mL — 128 μg/mL

7. Mechanisms of resistance
• Bacteria usually acquire resistance to
tetracycline from horizontal transfer of a gene
that either encodes an efflux pump or a
ribosomal protection protein.
• Efflux pumps actively eject tetracycline from
the cell, preventing the buildup of an
inhibitory concentration of tetracycline in the
cytoplasm.
• Ribosomal protection proteins interact with
the ribosome and dislodge tetracycline from
the ribosome, allowing for translation to
continue.

8. Precautions
• Use of the tetracycline antibiotics group is
problematic; they can:
• Discolor permanent teeth (yellow-gray-brown), from
prenatal period through childhood and adulthood
• Be inactivated by Ca2+ ions, so are not to be taken with
milk, yogurt, and other dairy products
• Be inactivated by aluminium, iron, and zinc, not to be
taken at the same time as indigestion remedies
(common antacids and over-the-counter heartburn
medicines)
• Cause skin photosensitivity, so exposure to the sun or
intense light is not recommended

9. • Cause drug-induced lupus, and hepatitis
• Cause microvesicular fatty liver
• Cause tinnitus
• Interfere with methotrexate by displacing it
from the various protein-binding sites
• Cause breathing complications, as well as
anaphylactic shock, in some individuals
• Affect bone growth of the fetus, so should
be avoided during pregnancy
• Fanconi syndrome may result from ingesting
expired tetracyclines

10. Other uses
•Since tetracycline is
absorbed into bone, it
is used as a marker of
bone growth for
biopsies in humans.

11. Cell culture
• Tetracycline is used in cell biology as a
selective agent in cell culture systems.
• It is toxic to prokaryotic and
eukaryotic cells and selects for cells
harboring the bacterial tet r gene,
which encodes a 399-amino-acid,
membrane-associated protein.

12. Mechanism of action
• Tetracycline inhibits protein synthesis by
blocking the attachment of charged
aminoacyl-tRNA to the A site on the
ribosome.
• Tetracycline binds to the 30S subunit of
microbial ribosomes.
• Thus, it prevents introduction of new
amino acids to the nascent peptide
chain.