My concern is that patients are self diagnosing that their PN is the direct result of taking Cipro or Levaquin long after they've taken it without any diagnostic test to prove this. If the PN didn't happen while they were taking these drugs it seems less reasonable to suspect that it was the cause if the PN happened weeks or months later.

PN is not an insidious condition happening inside us without knowing it. If the nerves are damaged then we should feel it very soon while taking it. Like heart damage with Vioxx or osteoporosis with Femara - these things are happening to our bodies while we are on these drugs but don't feel the effects (unless you break a hip or have a heart attack) and they have to be diagnosed with medical tests.

Other drug side effects are outward and would be felt while taking the drug - like flushing with niacin, or a rash or swelling of the tongue or hives, etc.. So, too, with PN. The symptoms would be more likely to be felt while on the drug, IMO.

Aspirin can cause tinnitus (it does with me). So, can I conclude that I took an aspirin 10 years ago and if I now have tinnitus that it is the cause?

In reading blogs of people who had many bad side effects from these drugs most started soon after taking and while on the drugs.

I think we need to proceed with caution when trying to make a direct connection to PN and drugs unless we have these symptoms while on them or shortly thereafter - not weeks, months or years later.