Hi,
Please ask the doctor to call in a RX for your son so you can pick it up at the drug store.
Antispasmodics/anticholinergic agents for GI tract like Bentyl ,Levsin(this also come in as sublingual tablet for faster action) Donnatal tablet or elixir. Belladonna tincture etc.on an as needed basis, or just for the period of time when symptoms occur.Do not take them on a schedule basis unless your doctor ok with it. I think a few of them do not require RX; just go to Walgreen or CVS to ask the pharmacist for recommendation;you may be able to get some antispasmodics for GI over the counter without Rx; Prevacid or Prilosec are Proton pump inhibitors and is not effective for the condition your son had.It is for the control of the stomach acid.
so, first go to drug store for recommendation for OTC products and 2nd, call doctors for RX for more precise and stronger RX for the condition.
And please say hi to Trevor for me.
God bless.