Anti-androgens: Cyproterone Acetate, Dutasteride, Finasteride

This includes:

1. Cyproterone acetate - an anti androgen.
2. Dutasteride and finasteride inhibit the enzyme 5α-reductase, which converts testosterone into dihydrotestosterone which is more potent.

Indications

• Cyproterone acetate inhibits spermatogenesis leading to reversible infertility (but not a male contraceptive)
• Severe hypersexuality in men i.e. increased libido as in de Clerembaults'
• Sexual deviation in men
• Prostate cancer²
• Treatment of acne and hirsutism in women³

It is advised to obtain informed consent prior to starting therapy with cyproterone acetate and a spermatogram.

Cautions

• If chronic alcoholism present then may be ineffective for male hypersexuality
• Monitor full blood counts at beginning and every 2 - 3 of months whilst treatment continues
• Monitor liver function tests regularly (same frequency as blood counts)
• Monitor adrenocortical function e.g. monitor for hyponatraemia and hyperkalaemia and perform 9am cortisol if suspicious
• May impair performance of skilled tasks

Contraindications

• Hepatic impairment
• Diabetes mellitus with vascular complications
• Sickle-cell anaemia
• Malignant disease
• Severe depression
• Thrombo-embolic disease

Adverse effects¹

• Fatigue
• Weight gain
• Breathlessness
• Gynaecomastia
• Hypersensitivity
• Skin rashes
• Osteoporosis
• Bone maturation and testicular development are inhibited when used in those under 18 years
• Hepatic impairment and failure

Animal studies have linked cyproterone acetate with hepatic tumours, thus weigh up all risks and benefits before initiating treatment.

Dutasteride and finasteride inhibit testosterone metabolism.

Indications

• Benign prostatic hypertrophy (BPH) - leads to reduction in prostatic size, improving urinary outflow. Alternatives to α blockers. Finasteride can be used with doxazosin in BPH.⁶
• Male pattern baldness in men - low dose finasteride has been used.

Cautions

• Reduce prostatic specific antigen thus not accurate in prostatic cancer
• Use of condom advised as they are excreted in semen and may be absorbed by pregnant females or females of child-bearing potential affecting an unborn male child

Contraindications

• Women (avoid handling broken tablets and capsules if of child-bearing potential), children and adolescents.

Adverse effects

• Reduced libido
• Sexual dysfunction; including impotence and impaired ejaculation
• Breast enlargement and pain
• Testicular pain
• Hypersensitivity reactions

Cyproterone acetate

• Has been associated with hepatic tumours in animals. In humans it is associated with jaundice, hepatitis and hepatic failure.⁷
• Therefore need regular monitoring of LFTs.
• Also monitor blood glucose in diabetic patients.
• Not for use in patients under 18 years - may delay bone and testicular development.

Dutasteride and finasteride

• Is excreted in semen and condom use recommended if sexual partner pregnant or likely to become pregnant.
• May take 6 months or longer for benefit.