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antibiotics (Fach) / Tetracyclines (Lektion)
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- active substances short acting: - Tetracycline - Chlortetracycline - Oxytetracycline long acting: - doxycycline - minocycline
- Mechanism and Mode of action Mechanism: 30 ribosomal subunit inhibition Mode: bacteriostatic; in urine very high concentrations -> bactericidal
- microbial spectrum Gram+ Gram- aerobic + anaerobic some protozoa: - Babesia (Doxy, but much better alternatives are available) - Theileria - Plasmodium - Entamoeba IC-organisms: - Mycoplasma - Mycoplasma haemophilis: FIRST CHOICE DOXY - Anaplasma phagocytophilum: FIRST CHOICE DOXY - Rickettsia: FIRST CHOICE - Chlamydophila: FIRST CHOICE - Wolbachia
- Wolbachia vector: canine heart worm treatment: - 30 days doxy treatment (because otherwise, when killing the worms, wolbachia would be released -> cytokine storm -> cardiovascular collapse) - then anthelminthic treatment with melarsamine
- Chlamydophila vector: birds diseases: zoonotic - respiratory tract infections - conjunctivitis tetracyclines are FIRST CHOICE defense
- Anaplasma phagocytolyticum vector: ticks (primarily in dogs), live on WBCs diseases: non-specific - fever - lameness - inappetence - exhaustion Doxy is FIRST CHOICE treatment
- Mycoplasma haemophilis most important in cats lives on RBCs diseases: haemolysis, aenaemia, icterus doxy is FIRST CHOICE treatment
- Mycoplasma spp. diseases: respiratory infections very important in swine and poultry
- Resistance very common, because only bacteriostatic ab ovo: Pseudomonas (except in UTI) aquired: - E. coli (always) - Salmonella (always) - Pasteurella - Mannheimia - Staphylococcus aureus
- application, absorption classic TCC: poor to moderate, impaired by food long-acting: excellent because more lipophilic
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- Doxycycline dose dog, cat: PO 10 mg/kg SID horse: PO 10 mg/kg SID, BID (not authorized) poultry: PO 7.5-15 mg/kg SID
- distribution classic TCCs: good (lipophilic) long acting TCCs: great distribution (even more lipophilic) -> penetrates special barriers (used in mengingitis, osteomyelitis etc.) and has good effect in IC-organisms (also accumulates -> t1/2 is very long
- metabolism low degree
- excretion classic TCCs: lipophilic, but a little bit more water-soluble -> mainly via urine long-lasting TCCs: lipophilic -> mainly via faeces and bile -> can be used in kidney-failure patients
- Indications respiratory infections (fastidious Gr-) Foot diseases (anaerobes) UTI (amoxicillin is first choice) metritis, mastitis osteomyelitis encephalitis prostatitis special IC-organsism: - lyme disease (Borellia) - Chlamydophilosis - FIRST CHOICE - Feline mycoplasmosis - FIRST CHOICE - infectious KCS in cattle (Moraxella bovis) - proliferative enteropathy in pigs & horses (Lawsonia intracellularis) - Nocardiosis - Anaplasmosis - Heart worm
- side effects not severe, but very frequent - yellow discoloration of teeth and bones in growing animals (-> contraindicated in children and show-animals) - irritation at site of injection -> when given PO, esophagus has to flushed afterwords, due to danger of necrosis - GI disturbances: vomitus, diarrhea - dysbacteriosis: mainly in herbivore-rodents and horses - collapse in rapid IV-injection (TCCS bind to calcium in blood > hypocalcemia > negative inotropic effect > decreases contractility of heart) - hepatotoxictiy in high doses - nephrotoxicity - photosensitivit caused by Doxy
- Contraindications Horses (only in special cases like Lawsonia enteropathy)