Hello, loss of taste can be because of dry mouth also which you already have.
I have a query for you that is there a loss or change of taste perception?
Certain medications can also cause change in taste sense.
Common cold, sinusitis, tonsillitis, may also cause change in taste perception.
Smoking, tobacco in any form, alcohol also change taste perception.
Other most common cause is cleaning your tongue with metallic tongue scrapers or vigorous use of toothbrush- these damage the taste buds and causes their atrophy gradually.
Your doctor in most likelihood has prescribed you multivitamins and
vitamin C tablets.
If the symptoms persist in absence of all above mentioned causes then I would advise you to consult your dentist in person so that he/she can examine you clinically and find out the exact cause.
T.C