* '''Not approved in food producing animals because of mutagenicity''' - in the UK this means that their is no safe withdrawal period and must never be used in food producing animals.
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* If metronidazole is injected subcutaneously or intramuscularly necrosis can result at the injection site.
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* Acute CNS toxicity has been reported in dogs.
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* Use carefully and at low doses with pregnant animals because of possible mutagenic effects.