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(for veterinary information only)
BRAND NAME: PANMYCIN, TETRACAP, TETRACYN,
SUMYCIN, TETRALAN
AVAILABLE AS
250 mg OR 500 mg
CAPSULES
OR AN
ORAL SUSPENSION
HOW THIS MEDICATION WORKS
Tetracycline was invented by Lloyd Conover working for Pfizer and was patented in 1955. Within three years it became the best selling antibiotic in the U.S.
The tetracycline antibiotic family provides broad anti-bacterial protection by inhibiting bacterial protein synthesis. The mammalian host's protein synthesis mechanisms are not affected because of
basic differences in the shape of the cellular machinery (the ribosomes) used to translate RNA into protein.
USES OF THIS MEDICATION
The body possesses many barriers through which antibiotics have difficulty penetrating (the nervous system, prostate gland, and eye are some examples). Infections behind these barriers can be
difficult to treat. Tetracycline is effective in treating prostate infections and can permeate cells to address intracellular parasites. It cannot reach adequate concentrations in the central nervous system to treat
infections there, though. Infectious agents for which members of the tetracycline family are especially helpful are, as mentioned, the intracellular ones including:
- Hemobartonella felis - now renamed Mycoplasma hemofelis (agent of
Feline Infectious Anemia)
- Borrelia bergdorferi (agent of Lyme's disease)
- Chlamydia psittaci (an agent of feline upper respiratory infection)
- Ehrlichia species (a tick-borne organism)
- Mycoplasma species (in upper respiratory & urinary infections)
Beyond antibiotic properties, tetracyclines also appear to have anti-inflammatory properties which have given them a place in treating assorted immune-mediated skin conditions in particular:
- Discoid Lupus Erythematosus
Another use seems to be against what are called Tetracycline Responsive Abscesses. It is not entirely clear what sort of organisms are represented here but something called an “L-form” (a bacterial
type that lacks a cell wall) is sometimes involved. Often these are responsive to the tetracycline class of drugs.
SIDE EFFECTS
Nausea and vomiting are the most commonly reported side effects of tetracycline in dogs and cats, particularly cats. Tetracycline should not be given with food as food binds the drug and prevents its
absorption into the body.
Drugs of the Tetracycline class have potential to permanently stain teeth if given to immature animals. (It binds to calcium which is needed for growing bones and teeth.)
Tetracyclines have potential to be toxic to the kidney. It is best to pick another drug in a patient with pre-existing kidney disease.
Long term use may induce actual urinary stones made of tetracycline.
Tetracycline can cause a false positive urine test for glucose.
INTERACTIONS WITH OTHER DRUGS
Antacids commonly contain calcium, which binds Tetracycline in the GI tract. If these medications are used together, neither may be absorbed properly and the benefits of both are lost. Iron containing
vitamin supplements produce the same problem. (Iron supplements are often used concurrently with Tetracycline to treat "Feline
Infectious Anemia.” Administration of these two medications should be separated by a couple of hours.)
Nausea may result if Tetracycline is used in combination with theophylline (an airway dilator). These two drugs might be used together to treat "Kennel Cough."
Drugs of the tetracycline class may make Digoxin (a heart medication) act stronger.
CAUTIONS AND CONCERNS
Tetracycline does not kill bacteria, it merely curtails their ability to reproduce. For the invading bacteria to be killed, the host's immune system must be active and effective. This may not be the
best choice medication for immune compromised patients.
Because of the calcium binding issues, Tetracycline should not be used in pregnant patients.
Tetracyclines should be stored at room temperature in light-tight containers.
Dosage adjustments are required if Tetracycline is to be used in patients with liver or kidney disease.
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