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

Logo RIDAQ-12,5 (tablet)

SCHEDULING STATUS:
S3

PROPRIETARY NAME
(and dosage form):

RIDAQ-12,5 (tablet)

COMPOSITION:
Each tablet contains: 12,5 mg
Hydrochlorothiazide

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 hypotensives agents such as guanethidine, methyldopa and rauwolfi alkaloids.
Pharmacokinetics
Hydrochlorothiazide 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. The route of elimination is via the kidneys.

INDICATIONS:
Mild to moderate hypertension alone or in combination with other anti-hypertensives.

CONTRA-INDICATIONS:
RIDAQ-12,5 is contra-indicated in patients with:
A known hypersensitivity to hydrochlorothiazide
Severe renal and/or hepatic insufficiency
Addison’s disease
Pre-existing hypercalcaemia

WARNINGS:
See “SPECIAL PRECAUTIONS

INTERACTIONS:
RIDAQ-12,5 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 RIDAQ-12,5 and lithium is not generally recommended since the association may lead to toxic blood concentrations of lithium.

PREGNANCY AND LACTATION:
Pregnancy
RIDAQ-12,5 crosses the placenta and there have been reports of neonatal jaundice, thrombocytopenia, and electrolyte imbalances following maternal treatment and is not recommended for use in pregnancy. Reductions in maternal blood volume could also adversely affect placental perfusion.
Lactation
RIDAQ-12,5 is distributed into breast milk, and not recommended for use in lactation.

DOSAGE AND DIRECTIONS FOR USE:
If a single dose is indicated, it should preferably be taken in the morning in order to minimise the effect of increased frequency of urination during sleep. It should be taken with or after meals to minimise stomach upset.
Hypertension
Adults
For the treatment of mild to moderate hypertension
12,5 mg daily.
As an adjunct in the treatment of hypertension
Adults
12,5 mg-25 mg daily in conjunction with an anti-hypertensive medicine. 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:
Side-effects
Frequently occurring side-effects:
Electrolyte imbalances
Administration of RIDAQ-12,5 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. 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.
Signs of electrolyte imbalance include dry mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pain and cramps, seizures, oliguria, and gastro-intestinal disturbances.
Less frequently occurring side-effects:
Metabolic disturbances and electrolyte imbalances
RIDAQ-12,5 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.
The urinary excretion of calcium is reduced.
Hypomagnesaemia.
Adverse changes in plasma lipids have also been noted but their clinical significance is unclear.
Nutritional disorders
Anorexia.
Gastro-intestinal disorders
Gastric irritation.
Nausea.
Vomiting.
Constipation.
Diarrhoea.
Intestinal ulceration has occurred following the administration of tablets containing thiazides with an enteric-coated core of potassium chloride.
Nervous system disorders
Headache.
Dizziness.
Photosensitivity reactions.
Paraesthesia.
Cardiac disorders
Postural hypotension.
Hepato-biliary disorders
Cholestatic jaundice.
Pancreatitis.
Blood disorders
Blood dyscrasias including thrombocytopenia and, less frequently, granulocytopenia, leucopenia, and aplastic and haemolytic anaemia have been reported.
Eye disorders
•Yellow vision. General disorders
•Hypersensitivity reactions include skin rashes, pulmonary oedema, and pneumonitis. Other
•Impotence. Special precautions
RIDAQ-12,5 should be used with caution in patients with impaired hepatic function since it increases the risk of hepatic encephalopathy.
Patients with hepatic cirrhosis are particularly at risk of hypokalaemia.
RIDAQ-12,5 should be given with caution in renal function impairment since it can further reduce renal function.
RIDAQ-12,5 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. Elderly patients are particularly susceptible to electrolyte imbalance.
There is a possibility that RIDAQ-12,5 may exacerbate or activate systemic lupus erythematosus in susceptible patients.

KNOWN SYMPTOMS OF OVERDOSAGE AND PARTICULARS OF ITS TREATMENT:
RIDAQ-12,5 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 is symptomatic. Recommended treatment for overdose includes immediate evacuation of the stomach; supportive, symptomatic treatment; monitoring of serum electrolyte concentrations and renal function and immediate institution of appropriate treatment for hyperkalaemia.

IDENTIFICATION:
A round, white tablet, flat with bevelled edges, bisected on one side.

PRESENTATION:
Plastic containers of 500 and 30 tablets. Patient ready packs containing 28 tablets.

STORAGE INSTRUCTIONS:
Store below 25ºC in a well-closed container. Protect from light and moisture.
KEEP OUT OF REACH OF CHILDREN.

REGISTRATION NUMBER:
A39/18.1/0399

NAME AND BUSINESS ADDRESS OF THE HOLDER OF THE CERTIFICATE OF REGISTRATION:
PHARMACARE LIMITED
Healthcare Park
Woodlands Drive
Woodmead
Sandton
2148

DATE OF PUBLICATION OF THE PACKAGE INSERT:
4 March 2005

596659

Updated on this site: December 2009
Source: Pharmaceutical Industry

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