Most people tolerate hydrochlorothiazide (HCTZ) well and do not appear to experience any side effects or problems while taking it. However, there are some potential dangers with hydrochlorothiazide that you should be aware of before starting the medication.
Hydrochlorothiazide may cause extreme low blood pressure in some people. This risk is higher in people who are on dialysis, have congestive heart failure, have diarrhea or vomiting, or sweat a lot. Seek medical attention immediately if you experience dizziness, lightheadedness, or fainting (as these are possible symptoms of low blood pressure). If you have fainted, stop taking hydrochlorothiazide until you have talked to your healthcare provider.
Other potentially dangerous side effects of hydrochlorothiazide that should be reported to a healthcare provider immediately include:
- Unexplained swelling of the head or neck (including the face, lips, tongue, or throat)
- Unexplained skin rash
- Difficulty breathing or swallowing
- Decrease in the amount of urine produced.
(Click Side Effects of Hydrochlorothiazide and Hydrochlorothiazide Warnings and Precautions to learn about other potential hydrochlorothiazide dangers, for information on who may not be able to safely take this medicine, and to find out what you should discuss with your healthcare provider before starting treatment.)