Based on the documents provided, I don’t have enough information to answer that question.

The documents state that for the FDA-approved treatment of methemoglobinemia, "Usually, one dose is sufficient, but a second dose may be given if symptoms persist after an hour." For other uses, no duration is specified. The provided text also includes a caution from medical experts that methylene blue "should only be used under a doctor's prescription."

Based on the provided documents, a common adverse effect of Methylene Blue is a "Bluish-green discoloration of urine (and feces)." Since Redox Blue's core ingredient is Methylene Blue, this would be the expected color.

Common adverse effects include bluish-green discoloration of urine (and feces).

The provided text states that Redox Blue products have "No additives, fillers, or synthetic ingredients," but it does not specify the full composition. Therefore, I don't have enough information to confirm the presence or absence of B vitamins.

This information is not provided in the context.

Redox Blue can be purchased on their website. They offer free domestic shipping within the United States for orders over $74.95.  They do not ship internationally.

This document does not specify how many types of methylene blue exist. It primarily discusses methylene blue as a single compound (methylthioninium chloride) used in various applications.  It does mention different formulations (e.g., intravenous, oral), and the "Redox Blue" brand sells it in tablet form, but these are delivery methods, not different types of the compound itself.

German chemist Heinrich Caro in 1876.

Methylene Blue was first prepared in 1876 by German chemist Heinrich Caro.

This information is not provided in the documents.