I've been keeping loaches for 8 years now and never had ich due to generous use of UV and quarantine procedures. My experience is shared by many others: UV = no more ich. If you run UV long enough, it can break the reproductive cycle of ich in your tank, making it extinct, and then you can stop using it as long as you don't add any new fish/plants/water. I think it can also be used to treat ich outbreaks since, like meds, it kills the free swimming form to prevent reinfestation of the fish. However, UV will do it without endangering the fish.
Why deal with meds that often kill your fish before the ich can? Why go through the heartbreak of having your loaches wiped out over and over again? Just get UV and be done with it.