I assume you mean the nitrites (not nitrates) of the 2 mentioned alkyl groups?
I don't know about Vic. but I can't seem to find anything for Australia which lists either of these chems as being regulated. I thought amyl is listed because it was once used for Angina. It has long since been replaced by glyceryl trinitrate (nitroglycerin) and other organic nitrates
Amyl, or more correctly isoamyl nitrite is used for cyanide poisoning. Every lab using cyanide salts or HCN must have ampoules of amyl nitrite on hand in case of CN poisoning. Even though it is said pure oxygen works as effectively, amyl is still kept on hand. You usually know when you are being poisoned with cyanide as you first taste almonds in your throat.
I remember it well, after first preparing HCN gas at the age of 12. In those days, even as a kid I had no trouble buying sodium cyanide, or anything for that matter. A local chemist even ordered the salt in for me. My my, how times have changed (thank goodness)
Butyl or isobutyl nitrite is probably what you find in sex shops. It is a cheap alternative. It's also possibly easier to sell and safer to use?
Years ago in NZ, it was relatively easy to obtain Amyl nitrite in cards of 12 glass ampoules. These were used as by possum hunters who baited with cyanide. The ampoules would be wrapped in a hanky and smashed. The resultant vapours when inhaled caused immediate flushing of the cheeks and a swelling of the head, and saved your life in event of an accident.
Certainly not my idea of a fun time, but there’s no telling for others tastes
If your argument for using amyl is sex related, and unless anal sphincter dilation is your desire, I suggest you instead try N2O at the moment of orgasm. Un-fuckin-believable, and a lot safer
By the way, NEVER have any alkyl nitrites with Viagra. The enzyme required for nontoxic metabolism of the nitrite is inhibited by Viagra. Nitrous oxide (N2O) is metabolized via a different pathway not using the same phosphodiesterase enzymes