INDICATIONS     CONTRA-INDICATIONS     DOSAGE     SIDE-EFFECTS     PREGNANCY     OVERDOSE     IDENTIFICATION     PATIENT INFORMATION

Logo RIDAQ - 25 TABLETS
RIDAQ - 50 TABLETS

SCHEDULING STATUS:
S3

PROPRIETARY NAME
(and dosage form)

RIDAQ - 25 TABLETS
RIDAQ - 50 TABLETS

COMPOSITION:
Each tablet contains :
RIDAQ - 25
Hydrochlorothiazide 25 mg
RIDAQ - 50 Hydrochlorothiazide 50 mg

PHARMACOLOGICAL CLASSIFICATION:
A 18.1 –Diuretics.

PHARMACOLOGICAL ACTION:
Hydrochlorothiazide is a diuretic which reduces the reabsorption of electrolytes from the renal tubules, thereby increasing the excretion of sodium, potassium and chloride ions, and consequently of water. It also slightly increases bicarbonate excretion without appreciable alteration of the acid-base balance or the pH of the urine. It has a lowering effect on the blood pressure and enhances the action of other hypotensive agents such as guanethedine, methyldopa and rauwolfia alkaloids.
It is absorbed from the gastro-intestinal tract, distributed throughout the extracellular space and diffuses across the placenta.
Diuresis occurs in about two hours, reaches a maximum in about four hours, and lasts for about twelve hours. Tolerance does not develop and therapeutic efficacy is maintained when it is administered over long periods, but patients may not respond if their glomerular filtration-rate is markedly reduced.

INDICATIONS:
Oedema due to sodium and water retention: Paradoxically, hydrochlorothiazide appears to have an antidiuretic effect on patients with diabetes insipidus and may be of value in the management of the disease.
Essential hypertension: preferably in combination with reduced doses of specific anti-hypertensive agents.

CONTRA-INDICATIONS:
Patients with an established hypersensitivity towards the drug. Severe renal and/or hepatic insufficiency.
Patients with Addison's disease. Patients with pre-existing hypercalcaemia.

DOSAGE AND DIRECTIONS FOR USE:
Adults - For the treatment of oedema:
An initial dose of 25 to 100 mg is usually given, and later reduced to a smaller maintenance dose, often given on alternative days.
An initial dose of up to 200 mg may be necessary in some patients, but larger doses have no additional effect.
Adults - As an adjunct in the treatment of hypertension:
25 –100 mg daily in conjunction with a reduced dose of the hypotensive agent.
Children
2,5 mg per kg body mass daily in two divided doses.
The dosage should not be higher than necessary to achieve the desired effect. Prolonged treatment may result in potassium ion loss. Potassium supplements may be necessary.

SIDE-EFFECTS AND SPECIAL PRECAUTIONS:
Hydrochlorothiazide may cause a number of metabolic disturbances especially at high doses. It may provoke hyperglycaemia and glycosuria in diabetic and other susceptible patients. It may cause hyperuricaemia and precipitate attacks of gout in some patients. Administration of thiazide diuretics may be associated with electrolyte imbalances including hypochloraemic alkalosis, hyponatraemia, and hypokalaemia. Hypokalaemia intensifies the effect of digitalis on cardiac muscle and administration of digitalis or its glycosides may have to be temporarily suspended. Patients with cirrhosis of the liver are particularly at risk from hypokalaemia. Hyponatraemia may occur in patients with severe heart failure who are very oedematous, particularly with large doses in conjunction with restricted salt in the diet. The urinary excretion of calcium is reduced. Hypomagnesaemia has also occurred. Adverse changes in plasma lipids have also been noted but their clinical significance is unclear. Signs of electrolyte imbalance include dry mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pain and cramps, seizures, oliguria, and gastro-intestinal disturbances. Other side-effects include anorexia, gastric irritation, nausea, vomiting, constipation, diarrhoea, headache, dizziness, photosensitivity reactions, postural hypotension, paraesthesia, impotence, and yellow vision. Hypersensitivity reactions include skin rashes, pulmonary oedema, and pneumonitis. Cholestatic jaundice, pancreatitis, and blood dyscrasias including thrombocytopenia and, less frequently, granulocytopenia, leucopenia, and aplastic and haemolytic anaemia have been reported. Intestinal ulceration has occurred following the administration of tablets containing thiazides with an enteric-coated core of potassium chloride.
Special Precautions:
Hydrochlorothiazide should be used with caution in patients with impaired hepatic function since they may increase the risk of hepatic encephalopathy. Patients with hepatic cirrhosis are particularly at risk from hypokalaemia. Hydrochlorothiazide should be given with caution in renal function impairment since they can further reduce renal function. Hydrochlorothiazide may precipitate attacks of gout in susceptible patients. Hydrochlorothiazide may cause hyperglycaemia and aggravate or unmask diabetes mellitus. Blood-glucose concentrations should be monitored in patients taking antidiabetic agents, since requirements may change. All patients should be carefully observed for signs of fluid and electrolyte imbalance, especially in the presence of vomiting or during parenteral fluid therapy. Hydrochlorothiazide can reduce urinary excretion of calcium, sometimes resulting in mild hypercalcaemia. Elderly patients are particularly susceptible to electrolyte imbalance. There is a possibility that hydrochlorothiazide may exacerbate or activate systemic lupus erythematosus in susceptible patients.
Interactions:
Hydrochlorothiazide may enhance the toxicity of digitalis glycosides by depleting serum-potassium concentrations. It may enhance the neuromuscular blocking action of competitive muscle relaxants, such as tubocurarine. It may enhance the effect of other antihypertensive agents, while postural hypotension associated with this therapy may be enhanced by concomitant ingestion of alcohol, barbiturates, or opioids.
The potassium-depleting effect of this diuretic may be enhanced by corticosteroids, corticotrophin, beta2-agonists such as salbutamol, or carbenoxolone. It has been reported to diminish the response to pressor amines, such as noradrenaline, but the clinical significance of this effect is uncertain. Concomitant administration of hydrochlorothiazide and lithium is not generally recommended since the association may lead to toxic blood concentrations of lithium.

KNOWN SYMPTOMS OF OVERDOSAGE AND PARTICULARS OF ITS TREATMENT:
Hydrochlorothiazide can produce acute renal failure either from overdosage, producing saline depletion and hypovolaemia or, occasionally, as a result of a hypersensitivity reaction.
In massive overdosage, treatment should be symptomatic and directed at fluid and electrolyte replacement. In cases of recent ingestion gastric lavage should be carried out.

IDENTIFICATION:
Both Ridaq - 25 and Ridaq - 50 are flat, pale peach, bisected tablets with bevelled edges and embossed with a mortar and pestle.
The 25 mg tablet has a diameter of 7 mm and the 50 mg tablet has a diameter of 8 mm.

PRESENTATION:
Ridaq –25
        Securitainers of 500 tablets.
Ridaq –50        Securitainers of 500 tablets.

STORAGE INSTRUCTIONS:
Store below 25°C, in airtight containers.
KEEP OUT OF REACH OF CHILDREN.

REGISTRATION NUMBERS:
Ridaq –25
        M/18.1/35
Ridaq –50        M/18.1/36

NAME AND BUSINESS ADDRESS OF THE APPLICANT:
Pharmacare Limited
7 Fairclough Road
Korsten
Port Elizabeth
6020

DATE OF PUBLICATION OF THIS PACKAGE INSERT:
28 January 1981

                D154
                        A & S PRINTERS

Updated on this site: May 2000

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