I Am A 71, Female, Retired And For The Past

I am a 71, female, retired and for the past few years when I get tired I lose my voice, it doesn't take long, waiting in a doctors office - I had a thyroid test and everything was ok there
I have been to several dr's, the last head dr gave me pridostimine 60 mg and as long as I take 3 a day I am pretty good, if I miss one - there goes the voice