I don't think the death rate is what would collapse the world economy. Even if the drug ended up killing more people it would still potentially help the economy. Especially if the side effects weren't know for years. Obviously I'm not advocating for this though.

My rule of thumb is to not take anything that’s been on the market for less then ten years. After ten years everyone figures out the real drawbacks and side effects.

thalidomide is still prescribed...

And now that we know it causes birth defects we can tell people about them in advance and control distribution closely...

Not to treat morning sickness in pregnant women!