Sounds like 'spir-ON-oh-LAK-tone'

Key points about spironolactone

  • Spironolactone is used to treat a number of different conditions such as heart failure, high blood pressure, polycystic ovary syndrome (PCOS) and gender affirming hormone therapy.
  • Spironolactone is commonly called Spiractin® or Spirotone®.
  • Find out how to take it safely and possible side effects.
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Spironolactone is used to treat a number of different conditions and related symptoms, including the following.

  • To reduce extra fluid in your body (called oedema) caused by conditions such as heart failure, liver disease or problems with your kidneys. It can reduce swelling in your ankles or feet, and shortness of breath.
  • High blood pressure (hypertension), when other blood pressure medicines don’t work as well.
  • Primary hyperaldosteronism – in hyperaldosteronism, your adrenal glands produce too much of a hormone called aldosterone. Spironolactone works by stopping the effects of aldosterone.
  • Facial hair growth and acne in women, as in polycystic ovary syndrome (PCOS).
  • As gender affirming hormone therapy, in combination with oestrogen. 

  • In New Zealand spironolactone is available as tablets (25 mg and 100 mg).
  • The dose of spironolactone will be different for different people depending on your medical condition and response to treatment.
  • Always take your spironolactone exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much spironolactone to take, how often to take it and any special instructions.

  • Timing: Spironolactone is usually taken once a day, in the morning. Some people taking higher doses may need to take a second dose later in the day. You can take spironolactone with or without food.
  • Limit or avoid alcohol while taking spironolactone: Alcohol may increase your chance of side effects such as dizziness.
  • Missed dose: If you forget to take your dose, take it as soon as you remember that day. If it is nearly time for your next dose, skip the missed dose and take your next dose at the usual time. Do not take 2 doses at the same time.

  • Avoid foods with a high potassium content: Spironolactone can increase the potassium levels in your blood (also called hyperkalaemia). You should avoid things with a high potassium content, such as 'salt substitutes' or low-sodium salt. You are at increased risk of hyperkalaemia if you:
  • Blood tests: You may need blood tests while taking spironolactone to check the amount of potassium and sodium in your blood, and to see how well your kidneys are working.
  • Other medicines: Spironolactone may interact with a number of medicines and herbal supplements so check with your doctor or pharmacist before starting spironolactone and before starting any new medicines. Also check with your pharmacist before taking anti-inflammatories that can be bought over the counter, such as diclofenac (eg, Voltaren Rapid), ibuprofen (eg, Nurofen), naproxen (eg, Naprogesic).

Like all medicines, spironolactone can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Feeling sick (nausea)
  • Stomach upset

  • These are quite common when you first start taking spironolactone and usually go away after the first few days.
  • Try taking your spironolactone dose with or after food.
  • Tell your doctor if troublesome.
  • Dizziness
  • Feeling light headed
  • Feeling faint when you stand up
  • Be careful when getting up from either lying down or sitting to avoid falls.
  • These effects puts you at risk of falls and injuries, especially if you are elderly.
  • Be careful when driving or using tools until you know how this medicine affects you.
  • Signs of too much potassium in your blood such as irregular heart beat (heart beat feels fluttery), tingling feelings, paralysis (difficulty moving) or difficulty breathing 
  • Spironolactone may cause increased potassium in your blood.
  • Tell your doctor immediately or phone Healthline 0800 611 116.
  • Signs of dehydration (losing too much salt and water) such as muscle cramps, weakness, dry mouth, thirst or passing unusually reduced amounts of pee
  • Tell your doctor immediately or phone Healthline 0800 611 116.
  • Signs of hormone changes such as breast development (in men), changes in menstrual cycle (periods) in women or sexual function problems   
  • Tell your doctor.
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product(external link)

The following links provide further information on spironolactone:

Spiractin(external link) Medsafe Consumer Information Sheets, NZ
Spironolactone(external link) (Māori(external link)) NZ Formulary Patient Information
Spironolactone in te reo Māori(external link)(external link) My Medicines, NZ, 2020
5 questions to ask about your medications(external link) Health Quality and Safety Commission, NZ, 2019 English(external link), te reo Māori(external link)


  1. Spironolactone(external link) NZ Formulary
  2. Reminder – hyperkalaemia caused by amiloride or spironolactone(external link) Medsafe Prescriber Update, NZ, 2021

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

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