(and dosage form)
Each Dyazide tablet contains 50 mg triamterene and 25 mg hydrochlorothiazide.
Triamterene is 2, 4, 7 triamino-6-phenylpteridine. Hydrochlorothiazide is 6-chloro-3, 4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide-1, 1-dioxide.
A. 18.1 Diurectics.
Dyazide is an oral diuretic, antihypertensive agent. Its hydrochlorothiazide component blocks reabsorption of sodium (and attendant chloride anions). Its triamterene component acts by a different mechanism it interferes with the exchange of sodium ions for potassium and hydrogen ions. Diuretic activity following a single dose is evident within the first hour, reaches a peak at 2 to 3 hours, and tapers off during subsequent 7 to 9 hours. Because of the potassium conserving effect of its triamterene component, Dyazide reduces the risk of hypokalaemia often seen with other diuretics. Therefore, it is of particular value in patients who might otherwise suffer from hypokalaemia and resultant side effects. The need for potassium supplements is virtually eliminated with the use of Dyazide. Hypochloraemic alkalosis, sometimes a problem with thiazides alone, has been reported with Dyazide.
Dyazide is indicated in the treatment of oedema associated with congestive heart failure, cirrhosis of the liver, the nephritic syndrome and in steroid-induced oedema and idiopathic oedema. Dyazide is useful in patients whose response to other diuretic therapy is inadequate and in cases where sodium retaining steroids are present. Dyazide is also indicated in the treatment of mild to moderate hypertension. (Triamterene alone has little or no antihypertensive effect of the hydrochlorothiazide component and the potassium-sparing effect of triamterene).
Dyazide is contra-indicated for further use in patients who exhibit progressive renal dysfunction, including increasing oliguria and increasing azotaemia or in patients whok develop hyperkalaemia while on the drug.
Dyazide should not be used in patients with pre-existing elevated serum potassium, s is sometimes seen in patients with impaired renal function. Increasing hepatic dysfunction in patients on Dyazide contra-indicates further use of the preparation.
Hypersensitivity to either drug in the preparation is a contra-indication.
Dyazide should not be used together with spironolactone as this may result in severe hyperkalaemia.
DOSAGE AND DIRECTIONS FOR USE
The usual adult starting dosage is one tablet twice daily after meals. When adequate control of oedema has been achieved, the patient may be maintained on one tablet daily. In some patients, one tablet every other day may be sufficient. The maximum daily dosage should not exceed four tablets per day.
The usual starting dosage is one tablet twice daily after meals. Subsequently, the dosage may be adjusted to the patients needs. Since Dyazide has an antihypertensive effect, its use with antihypertensive drugs requires reduced dosage of the latter agent. When Dyazide is added to an antihypertensive agent already being used as therapy the dosage of the other antihypertensive drug should be reduced particularly if it is a ganglionic agent. Subsequent adjustments of dosage should be made as required.
SIDE-EFFECTS AND SPECIAL PRECAUTIONS
Side-effects ordinarily mild, include:
Muscle cramps, weakness, dizziness headache and dry mouth, rash, urticaria purpura with or without thrombocytopenia, neutropenia and agranulocytosis have occurred, and other dermatological conditions; nausea and vomiting, diarrhea, constipation and other gastrointestinal disturbances. (Such nausea can usually be prevented by giving the drug after meals). It is seldom necessary to discontinue therapy because of side-effects.
It should be noted that symptoms of nausea and vomiting can also be indicative of electrolyte imbalance. (see Precautions.)
Electrolyte imbalance often encountered in such diseases as heart failure, renal disease, or cirrhosis of the liver may also be aggravated or caused independently by a diuretic agent including Dyazide.
Since Dyazide is a combination of two potent diuretics the possibility of electrolyte imbalance should be kept in mind when using high doses for prolonged periods or in patients on a salt-restricted diet. Periodic serum electrolyte determinations should be performed during therapy. Dyazide can cause mild to moderate nitrogen retention which is reversible upon withdrawal of the drug and is seldom observed with intermittent (every-other-day) therapy. Upon evidence of increasing azotaemia, however, the drug should be discontinued.
Cirrhotics with splenomegaly may have marked variations in their blood pictures-including thrombocyte and leucocyte levels-which are not related to drug therapy. Perioidic blood studies in these patients are recommended.
Cases of thrombocytopenic purpura and megaloblastic anaemia have been reported with triamterene; thiazides alone have caused jaundice, acute pancreatitis and blood dyscrasias including agranulocytosis, thrombocytopenia and leucopenia.
Since Dyazide has an antihypertensive effect, its use with another antihypertensive drug requires reduced dosage of the latter agent. When Dyazide is added to another antihypertensive already being used as therapy, the dose of the other antihypertensive drug should be reduced particularly if it is a ganglionic blocking agent. Subsequently adjustment of dosage should be made as required.
Dyazide because of its hydrochlorothiazide component may cause hyperglycaemia and glycosuria. In diabetics, the insulin requirement may be altered. Also, hyperuricaemia may be observed occasionally, with possible occurrence of gout. However, Dyazide does not appear to offer greater liability than that reported for hydrochlorothiazide alone.
Triamterene component may cause a decreasing alkali reserve with the possibility of metabolic acidosis. In cases of hypokalaemia, increased sensitivity to digitalis may occur, precipitating digitalis intoxication. Hyperkalaemia has been reported ranging in incidence from 4% in patients less than 60 years of age and higher in patients 60 years and older. Because of potassium-conserving effects of triamterene, hypokalaemia is an uncommon occurrence with the use of Dyazide.
Patients should not be placed on dietary Potassium supplements or potassium salts in conjunction
With Dyazide unless they develop hypokalaemia or their dietary intake of potassium is markedly impaired.
Thiazides have been shown to decrease arterial responsiveness to norepinephrine and to increase the paralyzing effect of tubocurarine; consequently caution should be observed in patients undergoing surgery. Periodic BUN and serum potassium determination should be made to check kidney function, especially in elderly patients and in patients with suspected or confirmed renal insufficiency or hepatic insufficiency.
Usage in Pregnancy:
Clinical experience and foetal studies in animals have shown no evidence to suggest that the preparation may be a cause of congenital abnormalities. Nevertheless, thiazides have been shown to pass through the placenta and also into breast milk. Cases of thrombocytopenia which may be a manifest of bone-marrow depression, which may sometimes be fatal, pancreatitis, or hypoglycaemia have been reported in newborn infants of mothers treated with thiazides.
The use of Dyazide in pregnant or nursing mothers should therefore be avoided.
KNOWN SYMPTOMS OF OVERDOSAGE AND PARTICULARS OF ITS TREATMENT
In the event of overdosage, it can be theorized that electrolyte imbalance would be the major concern. Other symptoms might be nausea and vomiting, other gastrointestinal disturbances, and weakness. Hypotension may occur and, if profound, pressor agents such as levarterenol may be used to maintain blood pressure levels.
As with overdosage of any drug, immediate evacuation of the stomach should be induced through emesis and gastric lavage. Careful evaluation of the electrolyte pattern and fluid balance should be made. There is no specific antidote.
Dyazide tablets are peach coloured, round, flatfaced, bevel-edged compressed tablets with a single score on one side, and a SKF plus code 93 embossed on the other.
Dyazide tablets are available in securitainers of 250 and 100, blisterpacks of 28.
Store below 25ºC in a dry place.
Keep out of reach of children.
REGISTRATION NUMBER (OR REFERENCE NUMBER)
NAME AND BUSINESS ADDRESS OF APPLICANT
PHARMAFRICA (PTY) LTD
33 Hulbert Road
DATE OF PUBLICATION OF THIS PACKAGE INSERT
26 April 1982
Updated on this site: May 2014
Source: Pharmaceutical Industry
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