Products
Androgens are commercially available as oral tablets and capsules, transdermal gels and transdermal patches, and injectables, among others. Testosterone was first isolated in the 1930s.
Structure and properties
Androgens generally have a steroidal structure and are related to testosterone. They are steroid hormones that are often present as esters in drugs.
Effects
Androgens (ATC G03B) have anabolic and androgenic (masculinizing) properties. They lead to the expression and maintenance of male sexual organs and characteristics. Major natural representatives include testosterone and its metabolite dihydrotestosterone. Precursors are dehydroepiandrosterone (DHEA) and androstenedione. Androgens are formed in the adrenal cortex and in the testes, and in women additionally in the ovaries. The endogenous formation of androgens is regulated by the central nervous system. Gonadotropin-releasing hormone (GnRH) from the hypothalamus leads to the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the anterior pituitary. LH and FSH promote testosterone formation and secretion, and FSH promotes spermatogenesis. Androgens have numerous functions in the body and affect the skin, muscles, skeleton, bone marrow, liver, kidneys, and central nervous system, among others. They are also necessary for libido, sexuality and for sperm formation and fertility. The effects are based on interaction with androgen receptors, which are transcription factors that affect gene expression. In hypogonadism, testosterone replaces the missing androgen in the bloodstream and ensures physiological concentrations.
Indications
Not all agents are approved for all indications:
- Hypogonadism in men (hormone replacement therapy, TRT, Testosterone Replacement Therapy).
- Puberty induction in boys with delayed onset of puberty.
- Suppression of excessive growth in length in boys.
- Osteoporosis in postmenopausal women.
- Endometriosis.
- Hereditary angioedema.
Off-label:
- Gender reassignment surgery in women.
- “Male menopause” (virile climacteric).
Dosage
According to the SmPC. Androgens are administered perorally, transdermally, buccally, and parenterally (intramuscularly), among others.
Abuse
Androgens have anabolic properties and increase muscle mass. They are abused as doping agents for sports, bodybuilding, and to increase physical attractiveness. Due to the possible adverse effects, they are not recommended. In the exogenous supply of androgens, the endogenous formation is reduced or stopped. See also under the articles Anabolic steroids and Doping agents.
Agents
- Anabolic steroids such as stanozolol, oxandrolone, oxymetholone and nandrolone (see there).
- Danazol (out of trade in many countries).
- Dehydroepiandrosterone (DHEA, DHEA-S, prodrug, also effective as estrogen).
- Testosterone
Other:
- Androstanolone
- Androstenedione
- Androstenediol
- Dihydrotestosterone
- Fluoxymesterone
- Mesterolone
- Methyltestosterone
Contraindications
Contraindications include (selection):
- Hypersensitivity
- Pregnancy
- Prostate cancer
- Breast cancer
- Liver tumors in patient history
- Hypercalcemia associated with a malignant tumor
For complete precautions, see the drug label.
Interactions
Androgens are substrates of CYP isoenzymes. Corresponding drug-drug interactions with CYP inhibitors and inducers are possible. Other interactions have been described with anticoagulants.
Adverse effects
Possible adverse effects of androgens include:
- Breast pain, gynecomastia (enlargement of the mammary gland in men).
- Muscle pain
- Prostate enlargement
- Hot flashes
- Weight gain
- High blood pressure
- Reactions at the administration site
- Increase in male body hair pattern.
- Increased sebum formation, acne, hair loss.
- Irritability, nervousness, aggressiveness
- Gastrointestinal disorders
- Sleep apnea
- Libido changes, increased erections
Testosterone can affect fertility by suppressing sperm formation (spermatogenesis). Exogenous testosterone inhibits the formation of the endogenous hormone in the testes, which promotes spermatogenesis. Testosterone therefore acts like a contraceptive for men, but is less reliable than “the pill” for women. In the case of illegally purchased anabolic steroids, there is also the question of product quality. They may contain impurities or the wrong active ingredients. The adverse effects of anabolic steroids are presented in the related article.
