In general, it's better to use an alternative medication if the side effects are undesirable.
In the case of non-steroidal anti-inflammatory drugs, there is plenty of choice. You could ask your doc for an alternative medication, but the chances are they are only available on prescription.
Advil (ibuprofen) is a different, slightly less powerful anti-inflammatory. You could use that instead during the day, and save the voltarol for the evening. (Note that the 2 drugs do the same thing - don't take the 2 of the so that they overlap because that would be like overdosing on one of them).