Published: 1 September 2016

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Reminder: Hyperkalaemia caused by Spironolactone and Renin-angiotensin System Medicine Interactions

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Prescriber Update 37(3): 36
September 2016

The United Kingdom's medicines regulator (Medicines and Healthcare products Regulatory Agency or MHRA) has recently noted an increase in reports of hyperkalaemia due to the use of spironolactone with angiotensin-converting enzyme inhibitors (ACEis) or angiotensin receptor blockers (ARBs)¹.

In New Zealand, the Centre for Adverse Reactions Monitoring (CARM) have received five cases of hyperkalaemia when an ACEi or an ARB was co-administered with spironolactone in the last 12 years.

Spironolactone is a potassium-sparing diuretic indicated for a number of conditions including essential hypertension and congestive heart failure^2,3. ACEis and ARBs can also reduce the loss of potassium via the kidneys and are often used in the management of patients with heart disease and hypertension³.

The risk of severe hyperkalaemia needs to be considered with the concomitant use of spironolactone and ACEis or ARBs, particularly in patients with renal impairment. Use the lowest effective doses of spironolactone and ACEis or ARBs if co-administration is required¹.

Serum potassium levels and renal function should be monitored regularly after initiation of spironolactone, an ACEi or an ARB, and again when increasing the dose^2,3. Treatment with spironolactone should be discontinued or temporarily withheld in hyperkalaemic patients².

Further information on medicines known to increase serum potassium levels can be found in a previous edition of Prescriber Update (www.medsafe.govt.nz/profs/PUArticles/Sep2015/Medicines&Hyperkalaemia.htm).

References

1. Medicines and Healthcare products Regulatory Agency (MHRA). 2016. Spironolactone and renin-angiotensin system drugs in heart failure: risk of potentially fatal hyperkalaemia. 17 February 2016. URL: www.gov.uk/drug-safety-update/spironolactone-and-renin-angiotensin-system-drugs-in-heart-failure-risk-of-potentially-fatal-hyperkalaemia (accessed 17 June 2016).
2. Mylan New Zealand Limited. 2013. Spiractin Data Sheet 26 November 2013. URL: www.medsafe.govt.nz/profs/datasheet/s/Spiractintab.pdf (accessed 16 June 2016).
3. Best Practice Advocacy Centre (BPAC). 2013. Managing patients with heart failure in primary care. February 2013. URL: www.bpac.org.nz/BPJ/2013/february/managing-heart-failure.aspx (accessed 16 June 2016).