I have a bottle of butyl nitrite, I haveen't ever had a problem with either butyl nitrite, or isobutyl nitrite degrading, I keep my isobutyl nitrite in a box with a load of various herbs, seeds and what have you, in a cool dry place, and it comes in an amber glass bottle (I buy it OTC, as "poppers").
Practically speaking, its not essential to keep it refrigerated, just out of light and reasnable cool, in a drawer or cupboard is sufficient.