Amiloride discontinuation leaves gap in treatment of aldosteronism

Cardiologists are mounting a campaign to restore access to the diuretic amiloride, saying its sudden discontinuation has left a gap in treatment options for patients with primary aldosteronism.

The potassium-sparing diuretic was taken off the market on March 12 by Alphapharm due to manufacturing issues, according to a notification by the Therapeutic Goods Administration (TGA).

But cardiologists were given little notice of the change to what they say is an essential drug and cornerstone of treatment of aldosteronism. Specialists told the limbic that amiloride may be the only option for patients with aldosteronism for whom the two potential alternatives, spironolactone and eplerenone are unsuitable or unaffordable.

Professor Michael Stowasser, Co-Director of the Endocrine Hypertension Research Centre, University of Queensland, said he only discovered amiloride was no longer available after a patient was told by their pharmacist that it had been discontinued.

The drug was an important treatment for the aldosteronism that occurred in 5-13% cent of people with hypertension,  he said.

“We see a lot of patients with aldosteronism  …  in our unit alone we probably have several hundred people on amiloride at the moment,” he told the limbic.

“Some people with the condition can be cured, about 25-30%, because it is only affecting the one adrenal and that can be removed. The remaining 70-75% can’t be cured because it affects both, but they can be treated with specific medication.”

Professor Stowasser said  spironolactone was the most commonly used treatment for aldosteronism, but it could cause sex steroid-related side effects such as gynaecomastia in males and menstrual irregularities in females.

“Amiloride does not cause these side effects and is therefore often preferred by patients,” he said.

Other alternatives include non-specific hypertension drugs which do not treat the cause of aldosteronism, and eplerenone which isn’t listed on the PBS, and may be unaffordable, he added.

Amiloride was still available in combinations with hydrochlorothiazide but this could place patients at risk of hypokalemia and hyponatraemia, he said.

Professor Stowasser said he was spearheading a campaign to bring the drug back to Australia, pulling together the High Blood Pressure Research Council of Australia, Cardiac Society of Australia and New Zealand, the Endocrine Society of Australia, the Heart Foundation, and the Australia and New Zealand Society of Nephrology.

“We hope to be able to put together either a combined letter from all groups co-signing it, or separate letters,” he said.

The manufacturer of amiloride, Alphapharm, has been contacted for comment.

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