**A longer course may be required if the clinical signs relapse. This holds true for most cases of ARD.
**A longer course may be required if the clinical signs relapse. This holds true for most cases of ARD.
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**Suitable drugs include oxytetracycline, tylosin, metronidazole. Oxytetracycline is the drug of first choice for idiopathic ARD but its use for secondary ARD is controversial. In addition, resistance is fast to develop with oxytetracycline. Tylosin and metronidazole may be more appropriate at targeting bacteria that are likely to be present in secondary ARD.
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**Suitable drugs include [[Tetracyclines|oxytetracycline]], [[Macrolides and Lincosamides|tylosin]], [[Nitroimidazoles|metronidazole]]. [[Tetracyclines|oxytetracycline]] is the drug of first choice for idiopathic ARD but its use for secondary ARD is controversial. In addition, resistance is fast to develop with [[Tetracyclines|oxytetracycline]]. [[Macrolides and Lincosamides|Tylosin]] and [[Nitroimidazoles|metronidazole]] may be more appropriate at targeting bacteria that are likely to be present in secondary ARD.