Brief Answer: You should test the electrolyte levels in blood. You should discuss with your doctor about changing Hydroclothyazide (diuretic) into another anti hypertensive drug. Detailed Answer: Hello, Thank you for using HCM. I understand your concern. Yes, Hydroclorthyazide is a diuretic. Eventhough, i think that your muscle pain and weakness may be due to electrolyte disturbances that Hydrochlorthyazide may cause (in addition to those caused by diarrhea), more than dehydration, as you restore water by drinking stimulated by thirst in the level your body needs it. There can be alterations of serum electrolytes including hypomagnesemia (low magnesium), hyponatremia (low sodium), and hypercalcemia (high calcium). The most important is hypokalemia, which may be experienced as weakness and fatigue, muscle cramps and pain. That s why you should test the electrolyte levels in blood, and to discuss with your doctor about changing it into another anti hypertensive drug, if there are important deviations in electrolyte levels and if there is not any other medical reason of using diuretics. The only antihypertensive drug that been added to the compendium of drugs linked to Celiac disease, are oral angiotensin-receptor blocker (ARB) such as olmesartan, eprosartan. Otherwise you can use all the other antihypertensive drugs to treat your hypertension. Meanwhile you can continue using Amlodipine safely. Try to drink plenty of water, and continue your your celiac diet. Hope this is helpful. Let me know if you need more clarifications. Otherwise please close and rate the answer. Kind Regards, Dr. Juarda