This preparation is indicated

• for the treatment of hypertension or edema in patients who develop hypokalemia on hydrochlorothiazide alone, and for those patients who require a thiazide diuretic and in whom the development of hypokalemia cannot be risked.
• It may be used alone or as an adjunct to other antihypertensive drugs, such as beta-blockers. Since this preparation may enhance the action of these agents, dosage adjustments may be necessary.

This fixed combination drug is not indicated for the initial therapy of edema or hypertension except in individuals in whom the development of hypokalemia cannot be risked.

Triamterene directly inhibits the exchange of Na for K and hydrogen in the distal renal tubule. Hydrochlorothiazide increases the excretion of Na and Cl ions, and consequently of water, by reducing electrolyte reabsorption from the renal tubules.

Hydrochlorothiazide is a thiazide diuretic. Thiazides affect the renal tubular mechanisms of electrolyte reabsorption, directly increasing excretion of sodium and chloride in approximately equivalent amounts. Indirectly, the diuretic action of Hydrochlorothiazide reduces plasma volume, with consequent increases in plasma renin activity, increases in aldosterone secretion, increases in urinary potassium loss, and decreases in serum potassium. The renin-aldosterone link is mediated by angiotensin II, so co-administration of an angiotensin converting enzyme (ACE) inhibitor tends to reverse the potassium loss associated with these diuretics.

The usual dose is one or two capsules given once daily, with appropriate monitoring of serum potassium and of the clinical effect.

Take this medication by mouth as directed by your doctor, usually once daily in the morning with or without food. It is best to avoid taking this medication within 4 hours of your bedtime to prevent having to get up to urinate.

If you also take certain drugs to lower your cholesterol (bile acid-binding resins such as cholestyramine or colestipol), take this product at least 4 hours before or at least 4 to 6 hours after these medications.

The dosage is based on your medical condition and response to treatment. Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day. It is important to continue taking this medication even if you feel well. Most people with high blood pressure do not feel sick.

May reduce the renal clearance of lithium. May antagonise diuretic effect with NSAIDs, corticosteroids, oestrogens, combined oral contraceptives. Enhanced effect with other hypotensive agents, baclofen, tizanidine. May decrease arterial responsiveness to norepinephrine. Increases responsiveness to tubocurarine. Risk of acute renal failure with indometacin. Increased risk of hyperkalaemia with reboxetine, tacrolimus. Increased risk of ototoxicity and nephrotoxicity with platinum compounds (e.g. cisplatin).

Antikaliuretic Therapy and Potassium Supplementation: Dyazide should not be given to patients receiving other potassium-sparing agents such as spironolactone, amiloride, or other formulations containing triamterene. Concomitant potassium-containing salt substitutes should also not be used. Potassium supplementation should not be used with Dyazide except in severe cases of hypokalemia. Such concomitant therapy can be associated with rapid increases in serum potassium levels. If potassium supplementation is used, careful monitoring of the serum potassium level is necessary.

Impaired Renal Function: Dyazide is contraindicated in patients with anuria, acute and chronic renal insufficiency or significant renal impairment.

Hypersensitivity: Hypersensitivity to either drug in the preparation or to other sulfonamide-derived drugs is a contraindication.

Hyperkalemia: Dyazide should not be used in patients with preexisting elevated serum potassium.

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.

Central Nervous System: Paresthesias, vertigo.

Ophthalmic: Xanthopsia, transient blurred vision.

Respiratory: Allergic pneumonitis, pulmonary edema, respiratory distress.

The routine use of diuretics in an otherwise healthy woman is inappropriate and exposes mother and fetus to unnecessary hazard. Diuretics do not prevent development of toxemia of pregnancy, and there is no satisfactory evidence that they are useful in the treatment of developed toxemia. Edema during pregnancy may arise from pathological causes or from the physiologic and mechanical consequences of pregnancy. Diuretics are indicated in pregnancy when edema is due to pathologic causes, just as they are in the absence of pregnancy.

Diabetes: Caution should be exercised when administering Dyazide to patients with diabetes, since thiazides may cause hyperglycemia, glycosuria, and alter insulin requirements in diabetes. Also, diabetes mellitus may become manifest during thiazide administration.

Impaired Hepatic Function: Thiazides should be used with caution in patients with impaired hepatic function. They can precipitate hepatic coma in patients with severe liver disease. Potassium depletion induced by the thiazide may be important in this connection. Administer Dyazide cautiously and be alert for such early signs of impending coma as confusion, drowsiness, and tremor; if mental confusion increases discontinue Dyazide for a few days. Attention must be given to other factors that may precipitate hepatic coma, such as blood in the gastrointestinal tract or preexisting potassium depletion.

Hypokalemia: Hypokalemia is uncommon with Dyazide; but, should it develop, corrective measures should be taken such as potassium supplementation or increased intake of potassium-rich foods. Institute such measures cautiously with frequent determinations of serum potassium levels, especially in patients receiving digitalis or with a history of cardiac arrhythmias. If serious hypokalemia (serum potassium less than 3.0 mEq/L) is demonstrated by repeat serum potassium determinations, Dyazide should be discontinued and potassium chloride supplementation initiated. Less serious hypokalemia should be evaluated with regard to other coexisting conditions and treated accordingly.

Electrolyte Imbalance: Electrolyte imbalance, often encountered in such conditions as heart failure, renal disease or cirrhosis of the liver, may also be aggravated by diuretics and should be considered during therapy with Dyazide when using high doses for prolonged periods or in patients on a salt-restricted diet. Serum determinations of electrolytes should be performed, and are particularly important if the patient is vomiting excessively or receiving fluids parenterally. Possible fluid and electrolyte imbalance may be indicated by such warning signs as: dry mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pain or cramps, muscular fatigue, hypotension, oliguria, tachycardia, and gastrointestinal symptoms.

Combined antihypertensive preparations

Store at controlled room temperature 20° to 25°C; excursions permitted to 15° to 30°C. Protect from light. Dispense in a tight, light-resistant container.