Hello,
I understand your concern.
Hyoscyamine is a drug that works by reducing the motility of the stomach as well as the stomach secretions. It should be effective for your condition, however, before taking this drugs there are several things to take in consideration.
First of all, you have to be sure that you are not allergic to it. I am assuming, since you found it in your cabinet, you must have used it before.
If you are above 65 years old it is not safe to take Hyoscyamine due to potential risks.
Please do not take Hyoscyamine if you take ANY kind of antidepressants, due to drug intereactions.
Do not take this drug if you are pregnant, or plan to become pregnant.
You should know that Hyoscyamine makes you drowsy, so please refrain from driving while under its effect.
If your symptoms persist, despite taking the medication, it is best to see a doctor for further investigation.
Wishing you good health and all the best.