Tetracyclines Flashcards
Naturally occuring TTC and fungi
Streptomyces spp
- oxytetracyclines
- chlortetracyclines
semisynthetic TTC
doxycyclines
minocyclines
short half life TTC
Tetracyclines
oxytetracyclines
chlortetracyclines
intermediat TTC
demeclocycline
long acting TTC
Doxycyclines
minocyclines
TTC: mechanism of action
30 s – inhibition of protein synthesis
Bacteriostatic – high concentration turns cidal
Antimicrobial spectrum of TTC
Bacteria
• mycoplasma haemofelis: resp infections
• rickettsia
• chlamydia: first choice
• Wolbachia spp
• Bordetella bronchiseptica: kennel cough, atrophic rhinits
• Borrelia: lyme disease, anaplasma phagocytophilum
Protozoae • Plasmodium spp • Entamoeba histolycia • Babesia spp • Theileria spp
Mechanism of resistance against TTC
Active efflux
AB degrading enzymes – destroys antibiotics
Multiresistance is common
Bacterias resistance towards TTC
Ab ovo
• Pseudomonas aeriguinosa
Aquired • Pathogenic E.coli • Salmonella spp • Pasteruella multocida • Mannheimia haemolytica • Staphylococcus aureus, streptococcus – 50% resistant
Pharmacokinetic features of classic TTC
Absorption: moderate, impaired by food (Ca, Mg)
Distribution: good - penetrates bone (yellow discolouration)
metabolism: low degree
Excretion: mainly urine . better
Pharmacokinetic features of long acting TTC
absorption: excellent
Distribution: excellent (bone)
Metabolism: low degree
Excretion: mainly large intestine, bile
Which type of TTC should not be given to farm animals?
Classic TTC
what is the excretion route of TTC in dogs
20% Urine
5% Bile
75% large intestine, secretion
indications for TTC
Lyme disease and ehrlichiosis (especially doxycyclines)
Chlamydiophilosos
Feline mycoplasmosis (formerly haemobartonellosis) Infectious
keratoconjunctivitis in cattle
• Moraxella bovis
Proliferative enteropathy in horses - lawsonian intracellularis
• Also important in swine
• Horses: doxyciclines - only drug, lethal if it goes untreated
Nocardiosis
Heartwater
Anaplasmosis
Heartworm – dirofilaris
• give for 30 days and then wait for 30 days, treat again for the heart worm in 30 days
Side effects of TTC
Tissue irritant Oral application - Fe + small dogs • Will cause irritation of oesophagus • Wash the esophagus with water or give food to try and get rid of them • Can caus necrosis of the wall GI disturbances • Vomit • Diarrhea Dysbacteriosis • Rabbits, horses herbivore rodents Rapid intravenous injection: collapse • TTC will bind Ca in the blood • Leads to hypocalcemia that causes the collapse • Decreases the contractility of the heart Tissue necrosis • IM or SC Yellow discolourixation of teeth: growing animals Heptatoxicity • Infrequent, can be very severe 1-2% • Long time + hepatoprotective (Silimarine, deoxycholic acid) Nephrotoxicity • Mild Photosensitivity • 50 factor applied to dog
