Side effects from metronidazole 500 mg
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Side Effects of Metronidazole 500 mg
Common Side Effects: Nausea, Abdominal Pain, and Diarrhea
Metronidazole, commonly prescribed for various infections, is generally well-tolerated but can cause mild to moderate side effects. The most frequently reported side effects include nausea, abdominal pain, and diarrhea. These symptoms are typically manageable and do not usually require discontinuation of the medication.
Neurotoxicity: Mental Confusion and Hallucinations
In rare cases, metronidazole can cause serious neurotoxic effects. A documented case involved a 65-year-old man who experienced severe mental confusion, hallucinations, and agitation when administered a high dose of 2.0 g daily. These symptoms were linked to peak serum concentrations of approximately 40 µg/ml and resolved within 24-48 hours after stopping the drug. Notably, these neurotoxic effects did not occur at a lower dose of 500 mg daily, suggesting a dose-dependent relationship.
Hematologic Effects: Leukopenia and Thrombocytopenia
Although rare, metronidazole can affect the hematopoietic system. In a study comparing metronidazole with ornidazole, transient leukopenia and thrombocytopenia were not observed in patients treated with metronidazole. However, the study did note that patients on metronidazole experienced a higher frequency of side effects overall.
Gastrointestinal Disturbances: Diarrhea and Altered Taste
Gastrointestinal disturbances are another common side effect of metronidazole. In a study comparing metronidazole with clindamycin for intra-abdominal infections, diarrhea was reported in four patients receiving metronidazole. Additionally, altered taste was a significant side effect, affecting 39% of patients in another study .
Reproductive and Genotoxic Effects
Animal studies have shown that high doses of metronidazole can have adverse effects on male fertility and cause genotoxic damage. In male mice, metronidazole significantly decreased the weight of reproductive organs and reduced sperm motility. It also induced anemia and chromosomal aberrations, indicating potential genotoxic effects. However, these findings are based on doses much higher than those typically prescribed to humans.
Conclusion
While metronidazole 500 mg is generally safe and effective for treating various infections, it can cause a range of side effects, from mild gastrointestinal disturbances to rare but serious neurotoxic and hematologic effects. Understanding these potential side effects can help in monitoring and managing them effectively during treatment.
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