Introduction

Antiandrogens are medications used in various medical contexts to inhibit the effects of testosterone, one of the main sex hormones. They are commonly used in the treatment of conditions where reducing androgen levels or their actions is needed. In this article, we’ll explore different types of antiandrogens, how they work, and their respective advantages and disadvantages.

Types of Antiandrogen:

Cyproterone Acetate (Cyproterone)

this is a tablet costing around £21 per month. This medication can have an effect on your liver and so requires additional monitoring – you would need to have Liver Function Tests (LFT’s) before starting and LFT’s every 3 months while on this medication.

Cyproterone works by blocking the androgen receptors in the body and also has some effect on lowering testosterone production. Cyproterone does have some quite significant potential side effects, so please read the leaflet below carefully.

https://www.medicines.org.uk/emc/files/pil.1120.pdf

Mechanism:
Cyproterone is a synthetic progestin and antiandrogen. It exerts its action by competing with androgens for binding to their receptors. This competition blocks the effects of androgens, ultimately reducing androgen activity in the body.

Pros:

• Effective Androgen Reduction: Cyproterone is known for its effectiveness in reducing androgen activity, making it valuable in various medical contexts.
• Transgender Hormone Therapy: It is commonly used as part of transgender hormone therapy to help individuals achieve desired hormonal changes.
• Treatment of Conditions: Cyproterone is prescribed to treat conditions such as hirsutism (excessive hair growth), acne, and prostate cancer when androgen suppression is needed.

Cons:

• Potential Side Effects: Like many medications, Cyproterone may have side effects. These can include liver issues and mood changes, which require monitoring.
• Liver Function Monitoring: Due to the potential for liver-related side effects, individuals taking Cyproterone need regular liver function tests to ensure their safety.
• Rare Risk of Meningioma: In very rare cases, there is a risk of developing a brain tumor known as meningioma associated with Cyproterone use. However, this risk is exceedingly uncommon.

Spironolactone:

This is a tablet which costs around £10 a month. This does require additional monitoring as it can have an effect on your kidneys and your blood pressure. We would need Kidney Function tests (U&E’s including potassium) and a blood pressure reading before starting and every 3 months while on this medication.

Spironolactone works by blocking androgen receptors in the body, so testosterone cannot exert its effects. 

https://www.medicines.org.uk/emc/files/pil.12013.pdf

Mechanism:
Spironolactone is a diuretic with antiandrogenic properties. It reduces androgen activity by inhibiting their production, primarily by interfering with the hormone aldosterone. This action helps reduce the effects of androgens in the body.

Pros:

• Transgender Hormone Therapy: Spironolactone is commonly used in transgender hormone therapy to help individuals achieve desired hormonal changes by reducing androgens.
• Treatment of Conditions: It is prescribed for conditions such as hirsutism (excessive hair growth), acne, and polycystic ovary syndrome (PCOS) where androgen suppression is beneficial.

Cons:

• Potassium Retention: A potential side effect of Spironolactone is potassium retention, which can lead to electrolyte imbalances. Monitoring potassium levels is essential when taking this medication.
• Frequent Urination: Frequent urination is a common side effect of Spironolactone due to its diuretic properties.

Finasteride:

This is a tablet costing around £10 a month and which doesn’t require any additional monitoring. Finasteride can be quite effective at lowering testosterone, although individual responses to this varies.

Finasteride works by blocking the conversion of testosterone to DHT, a more potent form of testosterone. 

https://www.medicines.org.uk/emc/files/pil.13543.pdf

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.

Pros:

• Effective for Certain Conditions: Finasteride is effective in the treatment of conditions like benign prostatic hyperplasia (BPH) and male pattern baldness, where reducing DHT levels is beneficial.
• Well-Tolerated: It is generally well-tolerated, and most users experience minimal side effects.

Cons:

• Effectiveness Compared to Other Antiandrogens: While effective, Finasteride may be less potent in lowering DHT levels compared to other antiandrogen medications.
• Gradual Results: It may take some time before noticeable improvements or results are seen, and consistent use is often required.

Gonadotropin-Releasing Hormone (GnRH) Agonists:

The safest and most effective anti-androgens are the GnRHa, which are known by various names including Triptorelin, Prostap, Synarel and Leuprorelin. These medications work by blocking the signals in the body telling your testes to make testosterone. 

These come as either an injection, which is administered every 12 weeks or as a nasal spray administered twice daily.

If you opt for the injection, you will need someone suitably qualified to administer it for you. This can be a nurse or a doctor, it could be a friend or family member who is qualified.  Alternatively, you can be trained to self-administer, or a family member or friend can be trained to administer it for you if needed.

The cost of the injection is around £270-£300 every 12 weeks, and the nasal spray £70-£100 every month – depending on the pharmacy you use. 

https://www.medicines.org.uk/emc/files/pil.4651.pdf

Mechanism:
GnRH (Gonadotropin-Releasing Hormone) agonists work by suppressing the production of sex hormones, including androgens (such as testosterone), by desensitizing the pituitary gland. This desensitization leads to a reduction in the release of gonadotropins, which control the production of sex hormones.

Pros:

• Highly Effective: GnRH agonists are highly effective in reducing androgen levels in the body.
• Versatile Use: They are used in various medical contexts, including prostate cancer treatment, endometriosis management, fertility control, the management of precocious puberty, and as a component of transgender hormone therapy.

Cons:

• Temporary Androgen Increase: One potential side effect is a temporary increase in androgen levels (a phenomenon known as a “flare”) before achieving suppression. This flare is usually transient.
• Menopausal-Like Symptoms: GnRH agonists can induce menopausal-like symptoms, including hot flashes, mood swings, and vaginal dryness.
• Bone Density Loss: Prolonged use of GnRH agonists without hormonal replacement therapy can lead to bone density loss and an increased risk of osteoporosis. Monitoring and appropriate hormonal supplementation are important when using GnRH agonists long-term.

Choosing the Right Antiandrogen

The choice of antiandrogen depends on the specific medical condition and the person’s individual needs and preferences. Make sure you have all the information before making an informed decision.

Conclusion

Antiandrogens play a significant role in managing various medical conditions related to androgen levels. Each type of antiandrogen has its unique mechanism of action, pros, and cons. The decision to use a particular antiandrogen should be based on the individual’s medical requirements and potential side effects.

Please be aware that prices can differ, but this represents the approximate average cost in the UK as of January 2024.