Hi & Welcome. Incomplete data like age, gender, purpose of taking Hydrochlorthiazide any associated medical illness or concomitant medications?? Yes, dry mouth can be a side effect of Hydrochlorthiazide. Hydrochlorothiazide is a diuretic ( water pill ) commonly prescribed alone or in combination with other medications to treat high blood pressure, edema (excess fluid held in body tissues) caused by the diseases of heart, kidney, and liver. Its most common side effects include dry mouth; thirst; nausea; weakness, tiredness; drowsiness; confusion; muscle weakness, pain, or cramps; fast heartbeat and other signs of dehydration and electrolyte imbalance. Your Physician Assistant-Certified (PA-C) seems to have increased the dose which has resulted in side effects due to excessive loss of fluid and salts from the kidneys. I advise you to consult your treating doctor to adjust the dose of Hydrochlorthiazide and meanwhile keep yourself hydrated by adequate intake of oral fluids and eat or drink increased amounts of potassium-rich foods (e.g., bananas, prunes, raisins, and orange juice) in your diet. Hope the advice given above would be beneficial. Take care. A feed back is appreciated.