Worst Pills, Best Pills

An expert, independent second opinion on more than 1,800 prescription drugs, over-the-counter medications, and supplements

Drug Profile

The information on this site is intended to supplement and enhance, not replace, the advice of a physician who is familiar with your medical history. Decisions about your health should always be made ONLY after detailed conversation with your doctor.

Limited Use [what does this mean?]
Generic drug name: triamterene and hydrochlorothiazide (tri AM ter een and hye droe klor oh THYE a zide)
Brand name(s): DYAZIDE, MAXZIDE
GENERIC: available FAMILIES: Potassium-sparing Diuretics, Thiazide Diuretics
Find the drug label by searching at DailyMed.

Pregnancy and Breast-feeding Warnings [top]

Pregnancy Warning

Triamterene crosses the placenta and exposes the fetus to the drug. Because of the potential for serious adverse effects to the fetus, this drug should not be used by pregnant women.

Breast-feeding Warning

Triamterene is excreted in animal milk and this may occur in humans. Because of the potential for serious adverse effects in nursing infants, you should not take triamterene while nursing.

Safety Warnings For This Drug [top]

FDA BLACK BOX WARNING

Abnormal elevation of serum potassium levels (greater than or equal to 5.5 mEq/liter) can occur with all potassium-sparing diuretic combinations, including these drugs. Hyperkalemia [elevated serum potassium levels] is more likely to occur in patients with renal [kidney] impairment and diabetes (even without evidence of renal impairment), and in the elderly or severely ill. Since uncorrected hyperkalemia may be fatal, serum potassium levels must be monitored at frequent intervals, especially in patients first receiving these drugs, when dosages are changed, or with any illness that may influence renal function.

Warning

A fixed-combination drug should not be the first drug used to treat your high blood pressure. You may not need more than one drug. If you do need two drugs, the fixed-combination product may not contain the dose of each drug that is right for you. Your doctor has to regularly check your condition and reevaluate the effect of the drug(s) you take. This may mean adjusting doses, and even changing drugs, to ensure proper treatment. This fixed-combination drug may be the best drug for you, but it should be used only after you have tried each of its ingredients separately, in varying doses. If the doses that you need to control your high blood pressure match those in this fixed-combination product, use it if the combination drug is more convenient.

Heat Stress Alert

This drug can affect your body’s ability to adjust to heat, putting you at risk of “heat stress.” If you live alone, ask a friend to check on you several times during the day. Early signs of heat stress are dizziness, lightheadedness, faintness, and slightly high temperature. Call your doctor if you have any of these signs. Drink more fluids (water, fruit and vegetable juices) than usual—even if you’re not thirsty—unless your doctor has told you otherwise. Do not drink alcohol.

Facts About This Drug [top]

These products are a combination of triamterene (DYRENIUM) and hydrochlorothiazide (ESIDRIX, HYDRODIURIL, MICROZIDE) and are used to treat high blood pressure (hypertension). Older adults should never use drugs that contain a fixed combination of triamterene and hydrochlorothiazide as a first-choice drug.

Public Citizen lists these drugs for Limited Use. 

Side effects

Triamterene can cause kidney stones, kidney failure and retention of too much potassium (especially if potassium...

These products are a combination of triamterene (DYRENIUM) and hydrochlorothiazide (ESIDRIX, HYDRODIURIL, MICROZIDE) and are used to treat high blood pressure (hypertension). Older adults should never use drugs that contain a fixed combination of triamterene and hydrochlorothiazide as a first-choice drug.

Public Citizen lists these drugs for Limited Use. 

Side effects

Triamterene can cause kidney stones, kidney failure and retention of too much potassium (especially if potassium supplements are also given), adverse effects that may be fatal.[1],[2] Because of these effects, we do not recommend that any older adult use triamterene alone.

In addition to triamterene’s dangers, there are good reasons not to use any fixed-combination drug for high blood pressure. A single drug is often enough to control high blood pressure. There is no reason to put yourself at extra risk by taking drugs you do not need.

First-line treatment for high blood pressure

If you have high blood pressure, the best way to reduce or eliminate your need for medication is by improving your diet, losing weight, exercising, and decreasing your salt and alcohol intake. Mild hypertension can be controlled by proper nutrition and exercise. If these measures do not lower your blood pressure enough and you need medication, hydrochlorothiazide, a water pill, is the drug of choice, starting with a low dose of 12.5 milligrams (mg) daily. It also costs less than other blood-pressure drugs.

There is growing evidence that thiazide diuretics, such as hydrochlorothiazide, significantly decrease the rate of bone mineral loss in both men and women because they reduce the amount of calcium lost in the urine.[3] Research now suggests that thiazide diuretics may protect against hip fracture.[4]

Since DYAZIDE and MAXZIDE contain 25 mg and 50 mg of hydrochlorothiazide respectively, it is not possible for older adults to start with a lower starting dose of 12.5 mg if either of these products is used. People responding to 12.5 mg of hydrochlorothiazide alone will have a lower risk of adverse effects and less need to use potassium supplements or a potassium-saving drug such as triamterene.

If your high blood pressure is more severe, and hydrochlorothiazide alone does not control it, another high-blood-pressure-controlling drug may be used instead. In this case, your doctor would prescribe the hydrochlorothiazide and the second drug separately, with the dose of each drug adjusted to meet your needs, rather than using a product that combines the drugs in advance in a fixed combination.

If you are taking this fixed-combination drug, ask your doctor about changing your prescription. 

Whatever drugs you take for high blood pressure, once your blood pressure has been normal for a year or more, a cautious decrease in dose and renewed attention to nondrug treatment may be worth trying, according to The Medical Letter on Drugs and Therapeutics.[5]

An editorial in the British Medical Journal (BMJ) stated:

Treatment of hypertension is part of preventive medicine and like all preventive strategies, its progress should be regularly reviewed by whoever initiates it. Many problems could be avoided by not starting antihypertensive treatment until after prolonged observation. ... Patients should no longer be told that treatment is necessarily for life: the possibility of reducing or stopping treatment should be mentioned at the outset.[6]

The May 2012 issue of Worst Pills, Best Pills News highlighted a recent BMJ study indicating that patients taking several types of commonly used antihypertensive medications are at increased risk of developing gout, a type of arthritis.

The BMJ study also showed that a small number of other antihypertensive drugs appear to have the opposite effect, decreasing the risk of gout.

All patients should be informed of the risk of gout with diuretics, beta-blockers, angiotensin-converting enzyme inhibitors (ACE inhibitors) and non-lorsartan angiotensin II receptor blockers (ARBs) when starting these medications or whenever the dose of the medications is increased [7].

The April 2013 issue of Worst Pills, Best Pills News discusses another recent BMJ study. This study suggests that an increased risk of acute kidney injury (AKI) is associated with combining nonsteroidal anti-inflammatory drugs (NSAIDs) with two antihypertensive drugs: a diuretic plus either an ACE inhibitor or an ARB. The risk was found to be highest during the first 30 days of starting an NSAID in patients who also are already taking a diuretic plus an ACE inhibitor or an ARB.

The study found that patients currently using a triple-therapy combination — a diuretic, an ACE inhibitor or an ARB, and an NSAID — have a 31 percent greater risk of developing AKI compared with current users of a diuretic plus an ACE inhibitor or an ARB without an NSAID.[8]

Regulatory actions surrounding hydrochlorothiazide

2011: In March, the Food and Drug Administration (FDA) issued the following warning concerning the use of hydrochlorothiazide products:

Hydrochlorothiazide, a sulfonamide, can cause an idiosyncratic reaction, resulting in acute transient myopia and acute angle-closure glaucoma. Symptoms include acute onset of decreased visual acuity or ocular pain and typically occur within hours to weeks of drug initiation. Untreated acute angle-closure glaucoma can lead to permanent vision loss. The primary treatment is to discontinue hydrochlorothiazide as rapidly as possible. Prompt medical or surgical treatments may need to be considered if the intraocular pressure remains uncontrolled. Risk factors for developing acute angle-closure glaucoma may include a history of sulfonamide or penicillin allergy.[9]

Before You Use This Drug [top]

Do not use if you have or have had:

  • high potassium levels
  • pregnancy or are breast-feeding

Tell your doctor if you have or have had:

  • kidney or liver problems
  • diabetes
  • small urine volume

Tell your doctor about any other drugs you take, including aspirin, herbs, vitamins, and other nonprescription products.

When You Use This Drug [top]

  • Do not use potassium supplements, salt substitutes (potassium chloride), or potassium-rich foods.
  • If you plan to have any surgery, including dental, tell your doctor that you take this drug.
  • Do not take any other drugs without first talking to your doctor—especially nonprescription drugs for appetite control, asthma, colds, coughs, hay fever, or sinus problems.
  • Because these drugs help you lose water, you may become dehydrated. Check with your doctor to make certain your fluid intake is adequate and appropriate, especially if you have vomiting or diarrhea.
  • Stay out of the sun as much as possible, and call your doctor if you get a rash, hives, or skin reaction. These drugs can make you more sensitive to the sun.
  • You may feel dizzy when rising from a lying or sitting position. When getting out of bed, hang your legs over the side of the bed for a few minutes, then get up slowly. When getting up from a chair, stay beside the chair until you are sure that you are not dizzy. 
  • If you plan to have any surgery, including dental, tell your doctor that you take this drug.
  • Do not take any other drugs without first talking to your doctor—especially nonprescription drugs for appetite control, asthma, colds, coughs, hay fever, or sinus problems.

How to Use This Drug [top]

  • If you miss a dose, take it as soon as you remember, but skip it if it is almost time for your next scheduled dose. Do not take double doses.
  • Do not share your medication with others.
  • Take the drug at the same time(s) each day.
  • Take the drug with food or drink.
  • Swallow extended-release tablets whole. Do not crush or break them. Take with a full glass (eight ounces) of water. Take your last dose of the day with a full glass of water at least an hour before bedtime.
  • Store at room temperature with lid on tightly. Do not store in the bathroom. Do not expose to heat, moisture, or strong light. Keep out of reach of children.

Interactions with Other Drugs [top]

The following drugs, biologics (e.g., vaccines, therapeutic antibodies), or foods are listed in Evaluations of Drug Interactions 2003 as causing “highly clinically significant” or “clinically significant” interactions when used together with any of the drugs in this section. In some sections with multiple drugs, the interaction may have been reported for one but not all drugs in this section, but we include the interaction because the drugs in this section are similar to one another. We have also included potentially serious interactions listed in the drug’s FDA-approved professional package insert or in published medical journal articles. There may be other drugs, especially those in the families of drugs listed below, that also will react with this drug to cause severe adverse effects. Make sure to tell your doctor and pharmacist the drugs you are taking and tell them if you are taking any of these interacting drugs:

alcohol, barbiturates, cholestyramine, COLESTID, colestipol, corticosteroids, dofetilide, lithium, narcotics, norepinephrine, NSAIDs, other drugs for lowering blood pressure, QUESTRAN, skeletal muscle relaxants (these are for both triamterene and hydrochlorothiazide), TIKOSYN.

Adverse Effects [top]

Call your doctor immediately if you experience:

  • difficulty breathing
  • coughing or hoarseness
  • dry mouth or increased thirst that does not go away quickly after you take a drink
  • fever
  • chills
  • irregular heartbeat, chest pain
  • weak pulse
  • mood or mental changes
  • confusion, convulsions, or irritability
  • muscle cramps, pain
  • unusual tiredness or weakness
  • black, tarry stools
  • blood in urine or stools
  • severe stomach pain with nausea and vomiting
  • joint, lower back, or side pain
  • painful or difficult urination
  • skin rash or hives
  • yellow eyes or skin
  • unusual bleeding or bruising

Call your doctor if these symptoms continue:

  • headache
  • dizziness
  • nausea or vomiting
  • stomach cramps and diarrhea
  • drowsiness
  • dry mouth
  • increased thirst
  • lack of energy
  • increased sensitivity to sunlight

Periodic Tests[top]

Ask your doctor which of these tests should be done periodically while you are taking this drug:

  • blood pressure
  • blood counts
  • blood potassium concentration
  • ECG

last reviewed March 31, 2021