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4 Foods to Avoid When Taking Hydrochlorothiazide

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Medically reviewed by Youssef Ghobrial, MD
Originally posted on The Checkup (June 3, 2024)

Certain things can affect the efficacy of this medication or make hypertension worse

Key takeaways

  • A low-sodium meal plan is usually the first dietary recommendation for people taking hydrochlorothiazide for high blood pressure.
  • Other foods to avoid while taking hydrochlorothiazide may include alcohol, foods high in sugar, and grapefruit juice.
  • Tell your healthcare provider if you take any over-the-counter supplements or remedies, such as vitamin D or magnesium, as they may increase the side effects of hydrochlorothiazide.

Hydrochlorothiazide is a prescription medication used to treat high blood pressure, also known as hypertension. “Hydrochlorothiazide, or HCTZ, belongs to a class of diuretics (water pills) known as thiazide diuretics,” says Ken Zweig, MD, an internist practicing in Arlington, Virginia. It’s also used to treat edema, which is swelling caused by the build-up of fluid in the body’s tissues. It works by helping the kidneys move water and electrolytes out of your body through urine. Off-label, it can be used to treat people with diabetes insipidus and calcium-containing kidney stones.

Hydrochlorothiazide is taken once daily with or without food, but patients may be advised to adjust their diet when taking it. Some foods to avoid when taking hydrochlorothiazide include those high in sodium and salt, as well as alcohol and grapefruit juice. It’s also recommended to follow a low-sodium diet, such as the DASH diet, and eat plenty of potassium-rich foods.

How hydrochlorothiazide works

Hydrochlorothiazide acts as a diuretic, leading to more frequent urination. “It forces the kidneys to release extra salt and fluid through the urine, helping to lower blood pressure and reduce fluid retention,” Dr. Zweig explains. It works quickly, within an hour or two of taking the medication. “It also causes vasodilation, which helps to reduce blood pressure” by opening your blood vessels, says Dr. Zweig.

4 foods to avoid with hydrochlorothiazide

What you eat can affect your blood pressure. Certain foods elevate it, while others lower blood pressure. Similarly, your diet can work against hydrochlorothiazide or increase the risk of side effects, Dr. Zweig says. Generally, those taking hydrochlorothiazide are advised to follow a heart-healthy, low-sodium diet. Here are some of the foods you should avoid when taking this medication.

1. High-sodium foods

When you’re diagnosed with hypertension, dietary changes are one of the first courses of action, says Mary Greene, MD, a board-certified cardiologist practicing in New York City. Specifically, foods that are high in sodium or salt are the first to be limited. “A high-sodium diet can counter the effects of HCTZ, so prescription drugs alone may not make a significant improvement on blood pressure,” explains Dr. Greene.

To maximize its effects, limit high-sodium foods when taking hydrochlorothiazide, such as:

  • Frozen foods
  • Canned foods
  • Pickled foods
  • Deli meats
  • Cheese
  • Condiments, sauces, and dressings
  • Highly-processed foods

While a low-sodium diet is recommended while taking hydrochlorothiazide, eliminating salt altogether on the medication can have an additive effect. This means that too little salt can lead to hypotension or too low blood pressure, Dr. Greene explains. To avoid this, your healthcare provider may suggest gradually lowering your salt intake before starting the medication. Dr. Greene recommends aiming for around 1.5-2 grams of salt or sodium per day while taking hydrochlorothiazide.

2. Alcohol

Drinking too much alcohol can lead to dangerously high blood pressure. As such, people with hypertension are often advised to limit their alcohol consumption.

Additionally, alcohol increases some of the side effects of hydrochlorothiazide. “It’s important to avoid consuming alcohol while taking HCTZ as this may cause dangerously low blood pressure,” Dr. Greene explains. It can also have side effects like lightheadedness, loss of consciousness, and dehydration, Dr. Zweig adds.

Another consideration is the increased risk of gout. “Both HCTZ and alcohol consumption increase the risk of gout,” Dr. Zweig says. “Anyone with a history of gout or risk factors for gout should certainly avoid drinking alcohol while taking HCTZ.”

RELATED: Understanding risk factors for gout

3. Sugary foods

Regardless of medication, people with high blood pressure are often advised to limit their intake of sugary foods, Dr. Zweig says. It’s no surprise that sugar is one of the foods to avoid when taking hydrochlorothiazide.

“HCTZ can cause a mild increase in blood sugar, so limiting sweets is important, especially for diabetics,” Dr. Zweig explains. Studies have found significant but small glycemic changes in people taking thiazide diuretics. Researchers recommend a change in dose for people who experience elevated blood sugar levels while taking HCTZ, though your healthcare provider may also prescribe a diet lower in sugar.

4. Grapefruit and grapefruit juice

Grapefruit is rich in vitamin C and other antioxidants. For many people, it can be part of a nutritious diet. However, it’s a common contraindication for people taking medications that treat high cholesterol or high blood pressure, such as statins.

That’s because grapefruit, grapefruit juice, and other citrus fruits can increase the amount of certain drugs in your body, according to the U.S. Food and Drug Administration (FDA). This could increase the risk of side effects of hydrochlorothiazide. Other citrus fruits to watch for could include pomelos, tangelos, and Seville oranges.

However, if a certain amount of time has passed since your last dose, you may be able to have some citrus fruit without issue. Ask a healthcare professional or pharmacist if it’s safe for you to eat grapefruit or drink grapefruit juice hours after taking hydrochlorothiazide.

Herbs and supplements to avoid with hydrochlorothiazide

If you use any herbs or over-the-counter dietary supplements, let your provider know. There are some uncommon interactions or side effects to be aware of, Dr. Zweig says.

“Patients should moderate the amount of vitamin D they take while on HCTZ,” says Dr. Zweig. “Both thiazide diuretics and vitamin D supplements increase calcium levels in the blood, and while uncommon, taking excess vitamin D with HCTZ can lead to unsafe levels of calcium.”

Some herbal remedies or supplements can increase the diuretic effect of hydrochlorothiazide. For example, magnesium can have a laxative effect in higher amounts, which could lead to diarrhea. Since HCTZ is a water pill that causes electrolyte depletion through the urine, the two together could lead to dehydration or dangerously low levels of sodium in the blood, Dr. Zweig explains. Other herbal remedies can also have a similar effect, leading to dehydration and electrolyte imbalance. Dr. Greene warns of the following:

  • Dandelion root
  • Hawthorne
  • Uva ursi
  • Juniper
  • Buchu
  • Cleavers
  • Horsetail
  • Gravel root

What should you eat while taking hydrochlorothiazide?

Patients taking hydrochlorothiazide to lower blood pressure are generally advised to follow a heart-healthy, low-sodium diet. This diet is also known as the Dietary Approaches to Stop Hypertension (DASH) diet. Drs. Zweig and Greene recommend it for those taking HCTZ.

The DASH diet was founded by the National Heart, Lung, and Blood Institute, and it emphasizes the following foods:

  • Grains
  • Meats, poultry, and fish
  • Vegetables
  • Low-fat or fat-free dairy products
  • Fats and oils
  • Nuts, seeds, dry beans, and peas

People taking hydrochlorothiazide should also prioritize potassium-rich foods. “When taking HCTZ, potassium is excreted in the urine, and you will need to replenish potassium levels through diet,” Dr. Greene explains.

To mitigate potassium loss while taking HCTZ, eat plenty of the following potassium-rich foods:

  • Avocados
  • Bananas
  • Beans and legumes
  • Leafy greens
  • Potatoes
  • Salmon

Your provider may prescribe potassium supplementation to help maintain normal levels while taking this medication.

Gastrointestinal side effects of hydrochlorothiazide

Hydrochlorothiazide is a prescription medication, so it’s important to talk to your healthcare provider about the side effects and potential risks. Common side effects of HCTZ include low potassium levels and frequent urination, but it can also affect the GI tract.

Consider seeking medication attention for the following side effects of HCTZ:

  • Diarrhea
  • Loss of appetite
  • Nausea
  • Difficulty swallowing
  • Stomach pain
  • Dizziness
  • Feeling like you’re going to pass out
  • Fainting
  • Dry mouth
  • Irregular heartbeats
  • Muscle aches
  • Weakness

“Despite the potential side effects, HCTZ is typically a very safe, inexpensive, and effective medication for the treatment of hypertension,” concludes Dr. Zweig. “Using this medication in the appropriate patient, along with proper diet and exercise, can control blood pressure and lower the risk of stroke, heart attacks, and kidney failure.”

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