Certainly you wouldn't tolerate serious adverse reactions for a
medication for nasal symptoms of allergy.  If the medication were
intended for a life-and-death indication (say, cancer chemotherapy) you
would have to tolerate more serious adverse reactions.
    The risk of the medication must be weighed against the anticipated benefit.

Steve

This is common.  There are two reasons.   Firstly a variety of symptoms are
prevalent in the "healthy" community.  In clinical studies all these get
recorded and included in the published results.  The only way of knowing
whether any symptom is likely to be due  to the drug rather than other
causes is to determine if it is significantly  more common in those taking
the drug than those taking placebo.

The second reason is the nocebo reaction, the opposite of the placebo effect
but also apparently the result of patient expectations and the power of
suggestion.  Thus, if patients think they are taking a powerful
pharmaceutical they will be especially vigilant regarding possible side
effects  and possibly even think themselves into them.

Peter Moran