What happens if i miss a dose of anastrozole?

Its okay: One missed dose will have little significance. Like most drugs, it stays in your system for a while and the effects/benefits last beyond the dose taken. Studies have shown that even when hormonal therapy is discontinued at 5 years, the curves plotting benefit continue to separate for several years afterwards.

Depends: What are you taking it for? If you're taking low dose to suppress aromatization it's not a big deal. If you're taking post-breast cancer therapy then it's more important not to miss a dose. However, Anastrozole has an extremely long half-life so missing one dose is likely not going to have any consequences.