Metrinox IV Adverse Reactions

Common adverse drug reactions (≥1% of patients) associated with systemic metronidazole therapy include: nausea, diarrhea, and/or metallic taste in the mouth.
Intravenous administration is commonly associated with thrombophlebitis. Infrequent adverse effects include: hypersensitivity reactions (rash, itch, flushing, fever), headache, dizziness, vomiting, glossitis, stomatitis, dark urine, and/or paraesthesia.
High doses and/or long-term systemic treatment with metronidazole is associated with the development of black hairy tongue, leukopenia, neutropenia, increased risk of peripheral neuropathy and/or CNS toxicity.
Metronidazole is listed by the International Agency for Research on Cancer (IARC) as a potential human carcinogen. Although some of the testing methods have been questioned, it has been shown to cause cancer in experimental animals. Nevertheless, it appears to have a fairly low potential for cancer risk and under most circumstances the benefits of treatment outweighs the risk.