Walaykum As Salaam, https://www.netdoctor.co.uk/medicines/ear-nose-throat/a8135/vicks-inhaler/#:~:text=How does Vicks inhaler work,when you breathe them in. In essence the inhaler works by giving off vapours when you inhale. Ulema have given similar rulings for purposely inhaling steam whilst fasting. The question is whether vapours from the inhaler have the same hukm as that of steam. Allah knows best but personally I refrain from using one whilst fasting.
As Salamu Alaykum Janab, I would add that a possible additional consideration is that inhalers do not emit a gas that has a discernable body whereas smoke and dust consist of a gas that does have a discernable body. So it would seem it is more like a strong smell.
Won't it be the same ruling as inhaling smoke and dust? That is if one purposely inhales the vapour from an inhaler whilst knowing that he/she is fasting then the fast becomes invalid. Similar ruling is given for inhaling bakhoor smoke if that person purposely inhales it whilst knowing that he is fasting.
