Dyazide

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Adverse effects are listed in decreasing order of severity.

Hypersensitivity: Anaphylaxis, rash, urticaria, subacute cutaneous lupus erythematosus-like reactions, photosensitivity.

Cardiovascular: Arrhythmia, postural hypotension.

Metabolic: Diabetes mellitus, hyperkalemia, hypokalemia, hyponatremia, acidosis, hypercalcemia, hyperglycemia, glycosuria, hyperuricemia, hypochloremia.

Gastrointestinal: Jaundice and/or liver enzyme abnormalities, pancreatitis, nausea and vomiting, diarrhea, constipation, abdominal pain.

Renal: Acute renal failure (one case of irreversible renal failure has been reported), interstitial nephritis, renal stones composed primarily of triamterene, elevated BUN, and serum creatinine, abnormal urinary sediment.

Hematologic: Leukopenia, thrombocytopenia and purpura, megaloblastic anemia.

Musculoskeletal: Muscle cramps.

Central Nervous System: Weakness, fatigue, dizziness, headache, dry mouth.

Miscellaneous: Impotence, sialadenitis.

Thiazides alone have been shown to cause the following additional adverse reactions:

Central Nervous System: Paresthesias, vertigo.

Ophthalmic: Xanthopsia, transient blurred vision.

Respiratory: Allergic pneumonitis, pulmonary edema, respiratory distress.

Other: Necrotizing vasculitis, exacerbation of lupus.

Hematologic: Aplastic anemia, agranulocytosis, hemolytic anemia.

Neonate and infancy: Thrombocytopenia and pancreatitis-rarely, in newborns whose mothers have received thiazides during pregnancy.

Skin: Erythema multiforme including Stevens-Johnson syndrome, exfoliative dermatitis including toxic epidermal necrolysis.

Serious side effects have been reported with triamterene/hydrochlorothiazide including:

• Hyperkalemia: Dyazide can raise your body's potassium to harmful levels, possibly causing the heart to stop beating. Tell your doctor if you have kidney disease or diabetes.
• Metabolic or respiratory acidosis: Dyazide can increase your potassium levels, leading to acidosis.
• Myopia (nearsightedness) or glaucoma, or vision loss due to an increase in eye pressure: Tell your healthcare provider right away if you have some or all of the following symptoms of myopia or glaucoma:
  • sudden, severe pain in one eye
  • decreased or cloudy vision
  • nausea and vomiting
  • rainbow-like halos around lights
  • red eye
  • eye feels swollen
• Electrolyte imbalances: Dyazide can dangerously alter your electrolyte levels. Electrolytes are important for the body to maintain normal functioning. Tell your doctor if you have a history of kidney disease.
• Hepatic coma: Tell your doctor if you have a history of liver disease.
• Renal stones: Treatment with Dyazide can cause kidney stones.
• Hyperuricemia: Dyazide can increase your levels of uric acid, leading to gout. Symptoms of gout include:
  • pain
  • swelling
  • discolored, peeling, or itchy skin
• Folic acid deficiency: Periodic blood tests are recommended for patients who may be affected by a decrease in folate levels.
• Metabolic and endocrine effects: Dyazide can impair your body’s metabolism and endocrine system. Tell your doctor if you have diabetes or parathyroid problems.
• Hypersensitivity reaction: An allergic reaction to Dyazide can occur. Call your doctor if you have one or more of the following symptoms of a hypersensitivity reaction:
  • rash or hives
  • difficulty breathing or swallowing
  • hoarseness
  • swelling

Dyazide can cause dizziness. Do not drive or operate heavy machinery until you know how it affects you.

Do not take Dyazide if you:

• have high potassium levels
• take other potassium-sparing medications such as spironolactone (Aldactone) and amiloride (Midamor)
• take potassium supplements
• have a history of poorly functioning kidneys
• are allergic to either triamterene or hydrochlorothiazide

Tell your doctor if you are breastfeeding or plan to breastfeed.

You should not take Dyazide if you are breastfeeding. It may be excreted in your breast milk and may harm your nursing child.

Triamterene and hydrochlorothiazide combination is used alone or with other medicines to treat water retention (edema) or high blood pressure (hypertension). High blood pressure adds to the workload of the heart and arteries. If it continues for a long time, the heart and arteries may not function properly. This can damage the blood vessels of the brain, heart, and kidneys, resulting in a stroke, heart failure, or kidney failure. High blood pressure may also increase the risk of heart attacks. These problems may be less likely to occur if blood pressure is controlled.

Triamterene and hydrochlorothiazide are both diuretic medicines (water pills). They reduce the amount of water in the body by increasing the flow of urine, which helps lower the blood pressure. Triamterene helps prevent your body from absorbing too much salt and keeps your potassium levels from getting too low.

This medicine is available only with your doctor's prescription.

• Tell all of your health care providers that you take this medicine. This includes your doctors, nurses, pharmacists, and dentists.
• Avoid driving and doing other tasks or actions that call for you to be alert until you see how Dyazide affects you.
• To lower the chance of feeling dizzy or passing out, rise slowly if you have been sitting or lying down. Be careful going up and down stairs.
• If you have high blood sugar (diabetes), talk with your doctor. This medicine may raise blood sugar.
• Check your blood sugar as you have been told by your doctor.
• Have your blood pressure checked often. Talk with your doctor.
• Have blood work checked as you have been told by the doctor. Talk with the doctor.
• This medicine may affect certain lab tests. Tell all of your health care providers and lab workers that you take this medicine.
• If you are on a low-salt or salt-free diet, talk with your doctor.
• Talk with your doctor before you drink alcohol or use other drugs and natural products that slow your actions.
• Watch for gout attacks.
• If you have lupus, Dyazide can make your lupus active or get worse. Tell your doctor right away if you get any new or worse signs.
• You may get sunburned more easily. Avoid sun, sunlamps, and tanning beds. Use sunscreen and wear clothing and eyewear that protects you from the sun.
• Tell your doctor if you have too much sweat, fluid loss, throwing up, or loose stools. This may lead to low blood pressure.
• If you are 65 or older, use this medicine with care. You could have more side effects.
• Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using Dyazide while you are pregnant.

Dyazide is a diuretic/antihypertensive drug product that combines natriuretic and antikaliuretic effects. Each component complements the action of the other. The hydrochlorothiazide component blocks the reabsorption of sodium and chloride ions, and thereby increases the quantity of sodium traversing the distal tubule and the volume of water excreted. A portion of the additional sodium presented to the distal tubule is exchanged there for potassium and hydrogen ions. With continued use of hydrochlorothiazide and depletion of sodium, compensatory mechanisms tend to increase this exchange and may produce excessive loss of potassium, hydrogen, and chloride ions. Hydrochlorothiazide also decreases the excretion of calcium and uric acid, may increase the excretion of iodide, and may reduce glomerular filtration rate. The exact mechanism of the antihypertensive effect of hydrochlorothiazide is not known.

The triamterene component of Dyazide exerts its diuretic effect on the distal renal tubule to inhibit the reabsorption of sodium in exchange for potassium and hydrogen ions. Its natriuretic activity is limited by the amount of sodium reaching its site of action. Although it blocks the increase in this exchange that is stimulated by mineralocorticoids (chiefly aldosterone), it is not a competitive antagonist of aldosterone and its activity can be demonstrated in adrenalectomized rats and patients with Addison’s disease. As a result, the dose of triamterene required is not proportionally related to the level of mineralocorticoid activity, but is dictated by the response of the individual patients, and the kaliuretic effect of concomitantly administered drugs. By inhibiting the distal tubular exchange mechanism, triamterene maintains or increases the sodium excretion and reduces the excess loss of potassium, hydrogen and chloride ions induced by hydrochlorothiazide. As with hydrochlorothiazide, triamterene may reduce glomerular filtration and renal plasma flow. Via this mechanism it may reduce uric acid excretion although it has no tubular effect on uric acid reabsorption or secretion. Triamterene does not affect calcium excretion. No predictable antihypertensive effect has been demonstrated for triamterene.

Duration of diuretic activity and effective dosage range of the hydrochlorothiazide and triamterene components of Dyazide are similar. Onset of diuresis with Dyazide takes place within 1 hour, peaks at 2 to 3 hours and tapers off during the subsequent 7 to 9 hours.

Dyazide is well absorbed.

Upon administration of a single oral dose to fasted normal male volunteers, the following mean pharmacokinetic parameters were determined:

where AUC(0-48), Cmax, Tmax and Ae represent area under the plasma concentration versus time plot, maximum plasma concentration, time to reach Cmax, and amount excreted in urine over 48 hours.

A capsule of Dyazide is bioequivalent to a single-entity 25 mg hydrochlorothiazide tablet and 37.5 mg triamterene capsule used in the double-blind clinical trial below (see Clinical Trials).

In a limited study involving 12 subjects, coadministration of Dyazide with a high-fat meal resulted in: (1) an increase in the mean bioavailability of triamterene by about 67% (90% confidence interval = 0.99, 1.90), p-hydroxytriamterene sulfate by about 50% (90% confidence interval = 1.06, 1.77), hydrochlorothiazide by about 17% (90% confidence interval = 0.90, 1.34); (2) increases in the peak concentrations of triamterene and p-hydroxytriamterene; and (3) a delay of up to 2 hours in the absorption of the active constituents.

The usual dose of Dyazide is one or two capsules given once daily, with appropriate monitoring of serum potassium and of the clinical effect (see WARNINGS, Hyperkalemia).

Electrolyte imbalance is the major concern (see WARNINGS section). Symptoms reported include: polyuria, nausea, vomiting, weakness, lassitude, fever, flushed face, and hyperactive deep tendon reflexes. If hypotension occurs, it may be treated with pressor agents such as levarterenol to maintain blood pressure. Carefully evaluate the electrolyte pattern and fluid balance. Induce immediate evacuation of the stomach through emesis or gastric lavage. There is no specific antidote.

Reversible acute renal failure following ingestion of 50 tablets of a product containing a combination of 50 mg triamterene and 25 mg hydrochlorothiazide has been reported. Although triamterene is largely protein-bound (approximately 67%), there may be some benefit to dialysis in cases of overdosage.

You should not use Dyazide if have kidney disease, urination problems, high levels of potassium in your blood, or if you are taking other diuretics similar to triamterene. Do not use potassium supplements, salt substitutes, or low-sodium milk unless your doctor has told you to.

Dyazide can raise your blood potassium to dangerous levels, especially if you have kidney disease, diabetes, severe illness, or if you are an older adult. Call your doctor right away if you have signs of high potassium: nausea, slow or unusual heart rate, numbness, tingling, muscle weakness, or loss of movement in any part of your body.

Drinking alcohol can further lower your blood pressure and may increase certain side effects of Dyazide.

Avoid a diet high in salt. Too much salt will cause your body to retain water and can make this medication less effective.

Do not use potassium supplements, salt substitutes, or low-sodium milk while you are taking Dyazide, unless your doctor has told you to.

Avoid becoming overheated or dehydrated during exercise and in hot weather. Follow your doctor's instructions about the type and amount of liquids you should drink. In some cases, drinking too much liquid can be as unsafe as not drinking enough.

Take Dyazide exactly as prescribed by your doctor. Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Dyazide is usually taken once per day.

You will need frequent blood tests to measure your potassium levels while taking this medicine, especially when you first start taking Dyazide or when your doses are changed. You may not any symptoms, but your blood work will help your doctor determine if you have high potassium (hyperkalemia).

Your heart function may also need to be checked using an electrocardiograph or ECG (sometimes called an EKG).

Severe illness can affect your potassium levels. Call your doctor if you have a serious illness, injury, or medical emergency.

If you need surgery or medical tests, tell the doctor ahead of time that you are taking medicine that contains hydrochlorothiazide. You may need to stop using the medicine for a short time.

If you are being treated for high blood pressure, keep using Dyazide even if you feel well. High blood pressure often has no symptoms. You may need to use blood pressure medicine for the rest of your life.

Store at room temperature away from moisture, heat, and light.

Usual Adult Dose of Dyazide for Edema:

Hydrochlorothiazide 25 to 50 mg-Triamterene 37.5 to 100 mg orally once a day

Comments:
-Patients who become hypokalemic on 50 mg of hydrochlorothiazide may be transferred directly to hydrochlorothiazide 50 mg-triamterene 75 mg orally once a day. Patients who become hypokalemic on 25 mg of hydrochlorothiazide may be transferred directly to hydrochlorothiazide 25 mg-triamterene 37.5 mg orally once a day.
-Patients in whom hypokalemia cannot be risked may be initiated on hydrochlorothiazide 25 mg-triamterene 37.5 mg orally once a day.

Uses:
-Treatment of hypertension or edema in patients who develop hypokalemia on hydrochlorothiazide alone.
-Initial therapy of hypertension or edema for patients in whom hypokalemia cannot be risked (e.g., patients on concomitant digitalis preparations or with a history of cardiac arrhythmias, etc.).

Usual Adult Dose of Dyazide for Hypertension:

Hydrochlorothiazide 25 to 50 mg-Triamterene 37.5 to 100 mg orally once a day

Comments:
-Patients who become hypokalemic on 50 mg of hydrochlorothiazide may be transferred directly to hydrochlorothiazide 50 mg-triamterene 75 mg orally once a day. Patients who become hypokalemic on 25 mg of hydrochlorothiazide may be transferred directly to hydrochlorothiazide 25 mg-triamterene 37.5 mg orally once a day.
-Patients in whom hypokalemia cannot be risked may be initiated on hydrochlorothiazide 25 mg-triamterene 37.5 mg orally once a day.

Uses:
-Treatment of hypertension or edema in patients who develop hypokalemia on hydrochlorothiazide alone.
-Initial therapy of hypertension or edema for patients in whom hypokalemia cannot be risked (e.g., patients on concomitant

UK: Use should be avoided. AU and US: This drug should not be used unless there are no safer alternatives. Excreted into human milk: Yes (hydrochlorothiazide); Unknown (triamterene) Excreted into animal milk: Yes (triamterene) Comments: Some authorities consider use of this drug acceptable during lactation if required by the mother and assuming a hydrochlorothiazide dose of 50 mg/day or less.