High Potassium No Threat With Spironolactone

Some prescribers of spironolactone (CaroSpir, Aldactone) for acne are still monitoring patients’ potassium levels despite the move to eliminate this practice, a new study found.

In a retrospective cohort study of over 100,000 female patients with acne, the percentage of healthcare providers who measured potassium levels within 180 days of starting spironolactone dropped from 41.4% in 2008 to 38.5% in 2018, reported John Barbieri, MD, MBA, of the University of Pennsylvania in Philadelphia, and colleagues.

As shown in their study online in JAMA Dermatology, this practice dropped the most among dermatologists — from 48.9% down to 41%. And the amount of dermatologists who would always monitor potassium levels likewise dropped from 10.6% to 4.2%.

As for internists who prescribed spironolactone for acne, the proportion who checked potassium levels within the first 180 days dropped from 39.7% to 37.7% from 2008 to 2018. However, the proportion of internists who said they always monitor potassium levels did not fall during this time, holding steady between 16% and 18%.

On the other hand, advanced practice clinicians, such as nurse practitioners and physician assistants, were overwhelmingly the most likely to monitor potassium levels, with the percentage actually increasing from 71.4% to 75.4% during this time period.

Concerns of hyperkalemia once circled with the use of spironolactone — a potassium-sparing diuretic that also lowers levels of the hormone aldosterone — subsequent data, however, have shown little benefit to monitoring levels in otherwise healthy young women. Other data have also shown no increased risk of hyperkalemia when spironolactone is co-prescribed with oral contraceptives containing drospirenone.

Because of this, several guidelines, including those from the American Academy of Dermatology, now suggest eliminating the practice of monitoring potassium levels in healthy young women being treated for acne.

“These findings highlight the well-documented challenges of implementing new evidence into clinical practice and the need for future implementation and dissemination research to address this practice gap,” the researchers wrote.

It’s not much of a surprise that dermatologists were the type of provider most likely to eliminate potassium monitoring in clinical practice: “Because much of the emerging literature on this topic has been published in dermatology journals, the lack of change in practice patterns among internists and advanced practice clinicians could reflect decreased awareness of these new data and a need for targeted educational interventions,” the team suggested.

“Another possibility is that increased clinical experience and comfort prescribing spironolactone has influenced the frequency of potassium level monitoring,” Barbieri and co-authors added.

This particular analysis included only female patients between the ages of 12 and 45 appearing in the Optum Clinformatics Data Mart. All women also had a diagnostic code of ICD-9 or ICD-10 for acne and were prescribed at least a 30-day course of spironolactone.

About half of these women (54,583) were treated by a dermatologist, while about a quarter (25,935) were treated by an internist; less than 1% (610) were treated by an advanced practice clinician.

Overall, only 0.22% of these patients were diagnosed with hyperkalemia during treatment with spironolactone, the researchers reported.