The OP suggested that one-off drugs rarely had long-term side effects. Thalidomide was raised as a counter example (an expectant mother might take it only once

The OP suggested that one-off drugs rarely had long-term side effects. Thalidomide was raised as a counter example (an expectant mother might take it only once). Oxycontin is not a counter-example; the long term side effects (as opposed to short-term overdose) require dosing over an extended period.