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Oct 26, 2020
6 min read

What are the most common side effects of hydrochlorothiazide?

The most common side effects of hydrochlorothiazide include more frequent urination, constipation or diarrhea, headache, erectile dysfunction, loss of appetite, nausea, vomiting, vision problems, and weakness. Adverse effects happened more frequently in those taking doses of 25 mg or more in clinical trials. Individuals taking a lower dose (12.5 mg) experienced the same rate of side effects as those given a placebo.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

Hydrochlorothiazide (HCTZ) is a thiazide diuretic (or “water pill”) used to treat high blood pressure or swelling (edema) by helping your body get rid of excess water, sodium, and chloride. Side effects of this prescription drug are dose-dependent, research shows, meaning the frequency of side effects is higher with larger doses (DailyMed, 2014).

The most common side effects of hydrochlorothiazide include more frequent urination, constipation or diarrhea, headache, erectile dysfunction, loss of appetite, nausea, vomiting, vision problems, and weakness. Adverse effects happened more frequently in those taking doses of 25 mg or more in clinical trials. Individuals taking a lower dose (12.5 mg) experienced the same rate of side effects as those given a placebo (DailyMed, 2014).

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Other potential side effects

Taking HCTZ may also lead to gout—a painful type of arthritis characterized by sudden pain, redness, and swelling of the joints—because this medication can cause high uric acid levels (hyperuricemia) (Jin, 2012). For people with a history of gout, hydrochlorothiazide may precipitate an attack (DailyMed, 2014).

HCTZ works to lower blood pressure by removing excess water from the body and reducing the amount of fluid in the blood. While this can be a good thing, sometimes it can cause dangerously low blood pressure (a condition known as hypotension). Symptoms of low blood pressure include dizziness or lightheadedness, blurred vision, fatigue, shallow breathing, rapid heart rate, confusion, and fainting. Drinking alcohol or using barbiturates or narcotics while taking hydrochlorothiazide may increase your chances of experiencing low blood pressure (DailyMed, 2014). 

Serious side effects

Hydrochlorothiazide affects electrolyte and fluid balance in the body, which can cause serious side effects. This medication may cause low sodium levels (hyponatremia), low potassium levels (hypokalemia), and low magnesium levels (hypomagnesemia). Electrolyte imbalances can cause dry mouth, irregular heartbeats (arrhythmias), muscle aches, nausea, thirst, tiredness, vomiting, and weakness. In some cases, these conditions can be dangerous and even life-threatening (DailyMed, 2014). Low potassium levels can also result in an elevated blood sugar level, which can be particularly problematic for patients with diabetes (Sica, 2011).

If you experience any symptoms of an electrolyte imbalance such as dry mouth, weakness, restlessness, confusion, or muscle pains, seek medical attention immediately. You should also get medical attention if you notice blistering or peeling skin, fever, sore throat, chills, visual changes, or unusual bleeding or bruising (NIH, 2019).

Some people may have an allergic reaction to hydrochlorothiazide (FDA, 2011). People who have experienced a sulfa drug allergy should not take this medication. An allergic reaction may cause hives, shortness of breath, trouble breathing, wheezing, skin rash, or swelling of the face, tongue, or throat. Seek medical attention immediately if you experience any of these signs of an allergic reaction.

What is hydrochlorothiazide?

HCTZ is a thiazide diuretic. There are several different types of diuretics. Thiazide diuretics are generally the first prescribed to help lower blood pressure, except for patients with chronic kidney disease (CKD) (Whelton, 2018). Thiazide diuretics such as HCTZ help the body get rid of sodium, chloride, and water, reducing water retention in the body. Hydrochlorothiazide acts on the kidneys, helping them lower blood pressure by removing excess fluid from the blood and releasing it in your urine.

The U.S. Food and Drug Administration (FDA) approved HCTZ to treat high blood pressure as well as swelling (edema) that’s caused by congestive heart failure or kidney disease (FDA, 2011). But you may also see medications that combine HCTZ with medicines. There are combination treatments available that contain HCTZ with beta-blockers, ACE inhibitors, angiotensin receptor blockers (ARBs), or calcium channel blockers to further lower blood pressure when a diuretic alone is not enough (Sica, 2011).

Hydrochlorothiazide also has off-label uses. This drug can be used to prevent kidney stones and to help people with diabetes insipidus, a rare medical condition characterized by an imbalance of salts and fluids in the body (NIH, 2019; UpToDate, n.d.). Diabetes insipidus (DI) is not the same as diabetes mellitus (high blood sugar). Patients with DI lose too much water in their urine, and HCTZ can be used to treat this condition (Bichet, 2019). 

HCTZ brand name and dosages

HCTZ is sold as a generic drug and as the brand-name medications Microzide, HydroDiuril, and Oretic. Generic forms may also be called “generic Microzide.” These versions of the drug are available as tablets in 12.5 mg, 25 mg, and 50 mg dosages. They are all typically taken once a day.

HCTZ is also used in drugs that combine this diuretic with another blood pressure medication. Research has shown that thiazide diuretics such as HCTZ may be used in combination with beta-blockers, ACE inhibitors, angiotensin receptor blockers (ARBs), and calcium channel blockers (Sica, 2011). That means HCTZ is in many different brand-name prescription medications, not all of which are available as generic drugs (Cooper-DeHoff, 2013).

You may see HCTZ combined with medications such as amlodipine, losartan, valsartan, and lisinopril

Lisinopril uses 

Lisinopril belongs to a class of medications called ACE inhibitors, which are used to lower blood pressure. It is not a diuretic but can be used together with diuretics such as hydrochlorothiazide in order to treat high blood pressure.

ACE-inhibitors such as lisinopril stop the body from making a natural hormone called angiotensin II that causes your blood vessels to constrict. This helps lower blood pressure. These medications also lower aldosterone, a hormone that causes sodium and fluid retention in the body. In this way, ACE inhibitors act similarly to diuretics, reducing water and sodium retention (Papich, 2016).

Research has found that blood pressure medications like ACE-inhibitors can be safely combined with thiazide diuretics such as HCTZ. These combination drugs may help lower blood pressure in individuals for whom either medication alone was not enough to treat high blood pressure (Sica, 2011).

Lisinopril drug interactions

Over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs), like Advil and Motrin, may decrease how effective lisinopril is at lowering blood pressure. Combining the two also increases your risk of kidney problems (FDA, 2014).

Lisinopril should also not be combined with other blood pressure medications that affect the renin-angiotensin-aldosterone system (RAS), including other ACE inhibitors, angiotensin-receptor blockers (ARBs), and a medication called aliskiren. Taking any of these medications at the same time as lisinopril may increase your risk of low blood pressure (hypotension), low potassium levels (hypokalemia), and kidney problems, including kidney failure (FDA, 2014).

Lisinopril brand name and cost

Lisinopril is available as a generic drug and is also sold as the brand name medications Prinivil and Zestril. All of these variations are available in dosages between 2.5 mg and 40 mg. The average retail price of lisinopril is about $15 for 30 tablets (GoodRX, n.d.).


  1. Bichet, D. (2019). Treatment of nephrogenic diabetes insipidus. In J.P. Forman (Ed.), UpToDate. Retrieved on Sep. 9, 2020 from
  2. Cooper-Dehoff, R. M. & Elliott, W. J. (2013). Generic Drugs for Hypertension: Are They Really Equivalent? Current Hypertension Reports, 15(4), 340-345. doi:10.1007/s11906-013-0353-4. Retrieved from 
  3. DailyMed. (2014). Hydrochlorothiazide capsule. Retrieved from
  4. Food and Drug Administration (FDA). (2011, May). HYDROCHLOROTHIAZIDE TABLETS, USP 12.5 mg, 25 mg and 50 mg Label. Retrieved from,040770s003lbl.pdf 
  5. Food and Drug Administration (FDA). (2014, December). Zestril® (lisinopril) tablets Label. Retrieved from 
  6. Food and Drug Administration (FDA). (2018, June 1). Generic Drug Facts. Retrieved Aug. 9, 2020, from
  7. GoodRx. (n.d.). Lisinopril Prices, Coupons & Savings Tips. Retrieved Sep. 14, 2020 from 
  8. Jin, M., Yang, F., Yang, I., Yin, Y., Luo, J. J., Wang, H., et al. (2012). Uric acid, hyperuricemia and vascular diseases. Frontiers In Bioscience (Landmark edition), 17, 656–669. doi:10.2741/3950. Retrieved from 
  9. National Institutes of Health (NIH). (2017). Thiazide Diuretics In LiverTox: Clinical and Research Information on Drug-Induced Liver Injury [Internet]. Bethesda, MD: National Institute of Diabetes and Digestive and Kidney Diseases. Retrieved from 
  10. National Institutes of Health (NIH). (2019, May 15). Hydrochlorothiazide: MedlinePlus Drug Information. Retrieved Sep. 10, 2020, from 
  11. Papich, M. G. (2016). Lisinopril. In Saunders Handbook of Veterinary Drugs (4th ed., pp. 454-455). Philadelphia, PA: Elsevier. doi:10.1016/B978-0-323-24485-5.00341-7. Retrieved from 
  12. Sica, D. A., Carter, B., Cushman, W., & Hamm, L. (2011). Thiazide and Loop Diuretics. The Journal of Clinical Hypertension, 13(9), 639-643. doi:10.1111/j.1751-7176.2011.00512.x. Retrieved from 
  13. UpToDate. (n.d.). Hydrochlorothiazide: Drug information (n.d.). Retrieved on Sep. 1, 2020 from
  14. Whelton, P. K., Carey, R. M., Aronow, W. S., Casey, D. E., Collins, K. J., Himmelfarb, C. D., et al. (2018). 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults. Journal of the American College of Cardiology, 71(19), E127-E248. doi:10.1016/j.jacc.2017.11.006. Retrieved from