Antiandrogens inhibit the effects of testosterone. We’ll explore different types of antiandrogens, how they work, and their respective advantages and disadvantages.
GnRH analogues
Leuprorelin (Prostap®)
- Costs £270-£300 a month.
- This is administered as an intramuscular injection every 4 to 12 weeks.
- It works by suppressing the production of the hormone GnRH, which results in the suppression of the production of oestrogen and testosterone.
- It has been established as safe and well-tolerated, with very few side effects.
Triptorelin (Decapeptyl®)
- Costs £270-£300 a month.
- This is administered as an intramuscular injection every 10 to 14 weeks.
- It works by suppressing the production of the hormone GnRH, which results in the suppression of the production of oestrogen and testosterone.
- It has been established as safe and well-tolerated, with very few side effects.
Nafarelin (Synarel®)
- Costs £70-£100 a month.
- This is administered as a nasal spray that is taken twice a day.
- It works by suppressing the production of the hormone GnRH, which results in the suppression of the production of oestrogen and testosterone.
- It has been established as safe and well-tolerated, with very few side effects.
5-alpha-reductase inhibitors
Finasteride
- Costs around £10 a month.
- This is a tablet that is taken daily.
- It works by blocking the enzyme 5-alpha-reductase, which results in the suppression of the conversion of testosterone to its most potent form dihydrotestosterone.
- It has been established as safe and well-tolerated, with very few side effects.
- It is less potent than other antiandrogen medications, so it can take longer to make noticeable changes.
Mechanism
Finasteride works by inhibiting the enzyme 5-alpha-reductase, which is responsible for converting testosterone into its more potent form, dihydrotestosterone (DHT). By blocking this conversion, Finasteride reduces the levels of DHT in the body.
Dutasteride
- This is a tablet that is taken daily.
- It works by blocking the enzyme 5-alpha-reductase, which results in the suppression of the conversion of testosterone to its most potent form dihydrotestosterone.
- It has been established as safe and well-tolerated, with very few side effects.
Other antiandrogens
Spironolactone
- Costs around £10 a month.
- This is a tablet that is taken daily.
- It works through a variety of mechanisms, including decreasing testosterone levels and stimulating oestrogen receptors.
- Most people who take spironolactone tolerate it well, but spironolactone does have recognised side effects, including low blood pressure (hypotension) and high potassium levels (hyperkalaemia).
- Spironolactone requires monitoring of blood pressure and blood tests to check the potassium level every 3 to 6 months.
- Spironolactone is not recommended in people with low blood pressure, high potassium levels, or kidney impairment.
- It can cause frequent urination.
Cyproterone acetate (Androcur®)
- Costs around £21 a month.
- This is a tablet that is taken daily.
- A powerful antiandrogen that suppresses the production of testosterone and blocks testosterone receptors.
- The majority of people who take cyproterone acetate tolerate it well, but cyproterone acetate can be associated with:
- Liver impairment
- Meningioma (a benign tumour of the lining of the brain)
- Cyproterone acetate requires blood tests to check the liver enzymes before starting and every 3 to 6 months.
- Cyproterone acetate is not recommended in people with evidence of liver impairment.