I don't remember any markings, but the capsule was the type where both ends join together rather then like the "pill", or solid type. The doctor that prescribed them has passed away and my present doctor can't locate his records.
If there were no markings then it wasn't a regulated prescription drug, maybe it was an herbal supplement or some kind or a vitamin.
All prescription drugs sold in the US are required to have some form of unique markings on them for ID purposes. OTC drugs, herbal supplements and vitamins, however, are not regulated and often have no markings and some even have the same markings on all their products so there is no way to tell one from the other.
Short of having it lab tested, there is no way to tell what it is without identifying markings.
My information is not guaranteed correct. I do not get them right all the time, but I do enjoy the hunt~