My spasms are also the kind that last 1-2 minutes, and are calmed somewhat by focused breathing. I joke with my wife that I'm having flashbacks from the LaMaze class we took when our first child was born. Also, there is no previous general nausea involved; sometimes just 10-15 seconds of my mouth watering followed by a cough-like vomiting spell.

I had hyoscyamine first because it was available as a sublingual dissolving tablet, but it got to where the dissolving residue sometimes trigger the gag reflex in my throat and led to more vomiting.

I (just me personally) have traded out the hyoscyamine for the Bentyl capsules. They've worked slightly better for me on the spasms, but a bigger advantage is that I don't wake up several times at night with extreme dry-mouth like I did on hyoscyamine.