According to Solco Healthcare, the shelf-life of Bentyl (Dicyclomine) capsules [NDC 43547-634] is listed as 24 months (or 2 years): solcohealthcare.com/product/dicyclomine-capsules

However, the following article from the FDA suggests that the listed 2 year shelf-life for Dicyclomine is arbitrary at best, as they declared certain lots of Doxycycline hyclate 100 mg capsules to be eligible for use beyond the manufacturer’s labeled expiration date by up to 7 YEARS for the purpose of strategic reserves and emergency preparedness: fda.gov/emergency-preparedness-and-response/mcm-legal-regulatory-and-policy-framework/expiration-date-extensions-certain-lots-doxycycline-hyclate-capsules

“Most of what is known about drug expiration dates comes from a study conducted by the Food and Drug Administration at the request of the military. With a large and expensive stockpile of drugs, the military faced tossing out and replacing its drugs every few years. What they found from their study is that 90% of more than 100 drugs, both prescription and over-the-counter, were perfectly good to use even 15 years after the expiration date. So, the expiration date doesn't really indicate a point at which the medication is no longer effective or has become unsafe to use. It's true the effectiveness of a drug may decrease over time, but much of the original potency still remains even a decade after the expiration date.”

Ref: health.harvard.edu/staying-healthy/drug-expiration-dates-do-they-mean-anything

Once a medication has expired, it is usually best to just dispose of it properly, but as you can see from the articles above, there may be valid exceptions to the rule depending on the type of medication and how it is stored.

Learn more about Dicyclomine: MedlinePlus

Hope this helps!