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Side Effects of Hydrochlorothiazide
There are a number of possible side effects of hydrochlorothiazide, including low blood pressure, weakness, diarrhea, and increased blood sugar. While most side effects do not require medical attention, you should notify your healthcare provider immediately if you experience any serious hydrochlorothiazide side effects such as seizures, unexplained swelling of the head and neck, or difficulty breathing.
As with any medicine, side effects are possible with hydrochlorothiazide (HCTZ). However, not everyone who takes the medicine will experience side effects. In fact, most people tolerate it well. If side effects of hydrochlorothiazide do occur, in many cases, they are minor, meaning they require no treatment or are easily treated by you or your healthcare provider.
(This article covers many, but not all, of the possible side effects with hydrochlorothiazide. Your healthcare provider can discuss a more complete list of hydrochlorothiazide side effects with you.)
Hydrochlorothiazide has been studied extensively in clinical trials, with thousands of people worldwide having been evaluated. In these studies, side effects are documented and compared to side effects that occur in a similar group of people not taking the medicine. This way, it is possible to see what side effects occurred, how often they occurred, and how they compared to the group not taking the medicine.
Based on these studies, hydrochlorothiazide side effects include:
- Weakness, dizziness, or a spinning sensation (vertigo)
- Low blood pressure (hypotension)
- Diarrhea, nausea, vomiting, constipation, and stomach cramps
- Increased blood sugar (hyperglycemia)
- Electrolyte imbalances, including low blood sodium (hyponatremia), low blood potassium (hypokalemia), and low blood chloride (hypochloremia)
- Sensitivity to the sun
- Muscle spasm
- Pancreatitis (inflammation of the pancreas)
- Hair loss (see Hydrochlorothiazide and Hair Loss)
- Erectile dysfunction, also referred to as ED or impotence (see Hydrochlorothiazide Sexual Side Effects).
Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD