TRIAMTERENE/CHLORTALIDONE

Hypertension Usually one tablet daily taken after breakfast. If necessary the dose may be increased to two tablets taken once daily. Oedema The usual dose is one tablet daily taken after breakfast. If oedema persists after seven to ten days the dose may be increased to two tablets daily.

Dosage in children has not been established and this medicine is recommended for the treatment of adults only. The elderly may require a lower dosage schedule.

Side effects are similar to those that have been associated with thiazide therapy and include nausea, dry mouth, constipation, leg cramp, headaches, dizziness and fatigue. Eye disorders: choroidal effusion (frequency not known). Cases of choroidal effusion with visual field defect have been reported after the use of thiazide and thiazide-like diuretics.

Rare cases of megaloblastic anaemia have been reported in association with triamterene. Reporting of suspected adverse reactions Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product.

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Caution should be exercised in patients with severe kidney disease, impaired liver function or progressive liver disease. As with thiazide diuretics and chlortalidone, treatment with Triamterene/Chlortalidone tablets may result in hyperuricaemia or the precipitation of acute gout in certain patients.

Potassium supplements should not be given with this medicine except in the presence of hypokalaemia. Chlortalidone has, in common with other sulphonamide diuretics, occasionally aggravated or precipitated diabetes mellitus. The effect is usually reversible on cessation of therapy.

Chlortalidone and related drugs may decrease serum protein bound iodine levels without signs of thyroid disturbance. Triamterene may cause a decreasing alkali reserve, with the possibility of metabolic acidosis. Although no clinically significant hyperkalaemia has occurred in studies with Triamterene/Chlortalidone tablets, all potassium conserving diuretic combinations can cause an abnormal elevation of plasma potassium.

It is recommended that measurements of potassium are made at the time of dosage adjustments and at appropriate intervals during therapy, particularly in elderly or diabetic patients with confirmed or suspected renal insufficiency. Signs or symptoms of hyperkalaemia include paresthesia, muscular weakness, fatigue, flaccid paralysis of the extremities, bradycardia, shock and ECG abnormalities.

If hyperkalaemia occurs in patients taking this medicine, it should be withdrawn, a diuretic substituted and potassium intake restricted. 5 mmol per litre, active measures should be taken to reduce it. Such measures include the intravenous administration of sodium bicarbonate solution or oral or parenteral glucose with a rapid-acting insulin preparation.

If progressive renal impairment becomes evident, Triamterene/Chlortalidone therapy should be withdrawn and alternative therapy instituted if necessary.

Choroidal effusion, acute myopia and secondary angle-closure glaucoma:

Sulfonamide or sulfonamide derivative drugs can cause an idiosyncratic reaction resulting in choroidal effusion with visual field defect, transient myopia and acute angle-closure glaucoma. Symptoms include acute onset of decreased visual acuity or ocular pain and typically occur within hours to weeks of drug initiation.

Untreated acute angle-closure glaucoma can lead to permanent vision loss. The primary treatment is to discontinue drug intake as rapidly as possible. Prompt medical or surgical treatments may need to be considered if the intraocular pressure remains uncontrolled.

Risk factors for developing acute angle-closure glaucoma may include a history of sulfonamide or penicillin allergy. Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.

Hypersensitivity to the individual components or to other sulphonamide-derived drugs. Progressive renal failure. Concomitant lithium therapy. 0 mmol/litre) or in patients receiving other potassium-sparing agents such as spironolactone or amiloride.