Commonly prescribed for: R.equi Infection
Species: Horses (foals)
Therapeutic Class: Macrolide Antibiotics
Clarithromycin is one of the newer macrolide antibiotics. Like other macrolide antibiotics, clarithromycin generally is bacteriostatic and works by inhibiting protein synthesis within susceptible bacteria. Clarithromycin is well absorbed orally. Macrolide antibiotics are not used in horses older than one year of age due to severe, potentially fatal colitis.
Rifampin is either a bacteriostatic or bactericidal antibiotic that inhibits DNA-dependent RNA polymerase in susceptible bacteria. It is well absorbed from the GI tract and penetrates many bodily tissues, including the cerebral spinal fluid. Rifampin is combined with other antibiotics to treat difficult walled-off infections because it increases the penetration of antibiotics into abscesses. It is always used in combination with other antibiotics because resistance develops rapidly when it is used alone. Rifampin is highly protein-bound and is metabolized by the liver.
Clarithromycin combined with rifampin is used in foals primarily for the treatment R.equi infection. For many years erythromycin combined with rifampin was the standard of care to treat R.equi infections. Recently, the newer advanced generation macrolides, such as clarithromycin and azithromycin, have gained popularity due to their better absorption and penetration characteristics. Research indicates that clarithromycin concentrates in pulmonary epithelial lining fluid (PELF) and in bronchial alveolar (BAL) cells of foals. Antibiotic levels for oral clarithromycin exceed the minimum inhibitory concentration in the PELF and BAL for a full 12 hours. Research performed by Giguere at the University of Florida concluded that foals treated with the combination of clarithromycin and rifampin exhibited significantly better radiographic improvement and, overall, had better short term and long term treatment success when compared to those treated with azithromycin/rifampin, or erythromycin/rifampin combinations. The treatment success-rate for foals with severe radiographic-lesions was greater than 80%.
Clarithromycin combined with rifampin may be used to treat em>Lawsonia intracellularis in foals. Older horses generally are treated either with tetracyclines, chloramphenicol, metronidazole, or other antibiotics.
The most-common side effects in all species are gastrointestinal. Mild to moderate diarrhea may occur in foals. Hyperthermia is a serious and potentially fatal side-effect that may be seen in foals. There is ample clinical evidence that foals on erythromycin are very sensitive to heat and possibly to bright sunlight and there have been anecdotal reports of similar hyperthermia with both clarithromycin and azithromycin. Because of this problem, many veterinarians do not turn out foals on macrolide antibiotics in the daytime and may severely limit their turnout time in general. Should hyperthermia occur, aggressive cooling using water and fans or air conditioning is helpful.
Remember to tell your veterinarian about any medications, vitamins, supplements, or herbal therapies that you are giving to your pet.
Wedgewood provides medication options that help ensure accurate dosing, especially for hard to medicate pets. Click below for a complete list of Wedgewood’s dosing forms and strengths.
DOSAGE FORM | BENEFITS | STRENGTHS |
---|---|---|
Oral Oil Suspension | Oil based oral suspension with a wide variety of flavoring options. | Multi |
Oral Paste | Flavored oral paste, packaged in a dosing syringe. | Multi |
Capsule | Oral medication available in gelatin or veggie capsule options. | Multi |
View all Clarithromycin / Rifampin options