When should metronidazole generally be avoided during treatment?

Metronidazole is generally avoided during the first trimester of pregnancy due to concerns regarding potential risks to the developing fetus. Though data regarding its safety during pregnancy are somewhat mixed, the first trimester is a critical period for fetal development, and caution is advised to prevent any possible teratogenic effects. The potential risks during this time can be more significant, making it prudent for healthcare providers to recommend alternatives or postpone treatment if possible.

While metronidazole can pass into breast milk, it is generally considered safe for breastfeeding mothers, as the benefits of treatment often outweigh the potential risks to the infant. Anxiety or high blood pressure is not directly contraindicated for the use of metronidazole, but contextual factors related to a patient's overall health and treatment objectives may influence the clinical decision to use it. Thus, avoiding metronidazole during the first trimester of pregnancy is the most sensible and widely supported recommendation.