Hydrochlorothiazide Side Effects

by on June 14, 2012

Hydrochlorothiazide, or HCTZ, is prescribed to patients with many different conditions because of its diuretic properties. The side effects of Hydrochlorothiazide often include muscle weakness, cramps, headache, and nausea. This medication can also aggravate symptoms of certain conditions, including diabetes and gout, and may interact with other drugs you are taking. Serious side effects are rare, but may be life threatening if not promptly treated.

Common Hydrochlorothiazide Side Effects

The most common side effect of HCTZ is a more frequent need to urinate. This usually goes away after 10 to 14 days.

Some individuals may also experience the symptoms below when they first start taking Hydrochlorothiazide:

  • Dizziness
  • Muscle weakness
  • Headache
  • Nausea
  • Vomiting
  • Diarrhea
  • Loss of appetite
  • Stomach pain
  • Cramps
  • Hair loss

If any of these symptoms are severe or don’t go away, particularly gastrointestinal side effects that could lead to dehydration, contact your doctor.

Serious Hydrochlorothiazide Side Effects

Most people will not experience any serious side effects when they take HCTZ as directed, but there are some risks associated with taking diuretics.

An allergic reaction to HCTZ can be dangerous or deadly. Do not take this medication if you are allergic to hyrdochlorothiazide and let your doctor know if you have had adverse reactions to sulfa drugs in the past. If you experience any side effects that could be a sign of a serious allergic reaction, seek immediate medical attention. These include:

  • Hives
  • Breathing difficulties
  • Swelling, especially in the face, lips, throat, or tongue

Occasionally, taking HCTZ can lead to other complications. Some side effects of HCTZ may pose more of a threat to certain individuals. In rare cases, individuals may develop pancreatitis, elevated blood sugar, and nutrient deficiencies that could have severe outcomes. Contact your doctor immediately if you experience any of the side effects below.

  • Vision changes or blurred vision
  • Severe dizziness or fainting
  • Fast or irregular heartbeat
  • Shallow or difficult breathing
  • Fever
  • Peeling or blistering skin
  • Dry mouth
  • Excessive thirst
  • Prolonged diarrhea or vomiting
  • Numb, tingly feeling
  • Muscle pain
  • Unexplained weakness
  • Jaundice, or yellowing of the skin or eyes

Be sure to drink plenty of fluids while taking HCTZ and avoid strenuous physical activity that could increase the risk of dehydration. If you experience any other unusual symptoms, be sure to let your doctor know.


According to research, HCTZ is not likely to cause harm to an unborn baby if it is used during pregnancy, but there are not substantial human studies to know for sure. If you pregnant or planning to become pregnant, talk to your doctor before taking HCTZ. In some cases, the benefits of this medication are worth the associated risks but that is a decision that should be made by you and your caregiver. HCTZ will pass through breast milk and may have adverse effects on a nursing infant. If you are breastfeeding, you should not take HCTZ.


It is easy to become dehydrated while taking a diuretic, especially if gastrointestinal side effects are present. Dehydration can become serious very quickly so it is important for HCTZ users to monitor their fluid intake as well as their activity level. Water is typically the best choice, but your doctor may suggest the intake of other fluids. Avoid drinking alcohol while taking HCTZ. It can increase the risk of dehydration and can also cause a serious decrease in blood pressure.

HCTZ is a preferred diuretic to eliminate swelling and water retention in a number of conditions. There are very few HCTZ side effects and those that do occur are typically mild. Most serious side effects can be prevented with proper diet, exercise, and plenty of fluids.