Mepitiostane, sold under the brand name Thioderon, is an orally active antiestrogen and anabolic–androgenic steroid (AAS) of the

dihydrotestosterone Dihydrotestosterone (DHT, 5α-dihydrotestosterone, 5α-DHT, androstanolone or stanolone) is an endogenous androgen sex steroid and hormone primarily involved in the growth and repair of the prostate and the penis, as well as the production o ...

(DHT) group which is marketed in

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

as an

antineoplastic agent Chemotherapy (often abbreviated chemo, sometimes CTX and CTx) is the type of cancer treatment that uses one or more anti-cancer drugs ( chemotherapeutic agents or alkylating agents) in a standard regimen. Chemotherapy may be given with a cura ...

for the treatment of

breast cancer Breast cancer is a cancer that develops from breast tissue. Signs of breast cancer may include a Breast lump, lump in the breast, a change in breast shape, dimpling of the skin, Milk-rejection sign, milk rejection, fluid coming from the nipp ...

. It is a

prodrug A prodrug is a pharmacologically inactive medication or compound that, after intake, is metabolized (i.e., converted within the body) into a pharmacologically active drug. Instead of administering a drug directly, a corresponding prodrug can be ...

of epitiostanol. The drug was patented and described in 1968.

Medical uses

Mepitiostane is used as an antiestrogen and antineoplastic agent in the treatment of breast cancer. It is also used as an AAS in the treatment of

anemia Anemia (also spelt anaemia in British English) is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin availabl ...

renal failure Kidney failure, also known as renal failure or end-stage renal disease (ESRD), is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney fa ...

. A series of

case report In medicine, a case report is a detailed report of the symptoms, signs, diagnosis, treatment, and follow-up of an individual patient. Case reports may contain a demographic profile of the patient, but usually describe an unusual or novel occurrenc ...

s have found it to be effective in the treatment of an

estrogen receptor Estrogen receptors (ERs) are proteins found in cell (biology), cells that function as receptor (biochemistry), receptors for the hormone estrogen (17β-estradiol). There are two main classes of ERs. The first includes the intracellular estrogen ...

(ER)-dependent

meningioma Meningioma, also known as meningeal tumor, is typically a slow-growing tumor that forms from the meninges, the membranous layers surrounding the brain and spinal cord. Symptoms depend on the location and occur as a result of the tumor pressing ...

s as well.

Side effects

Mepitiostane shows a high rate of virilizing

side effect In medicine, a side effect is an effect of the use of a medicinal drug or other treatment, usually adverse but sometimes beneficial, that is unintended. Herbal and traditional medicines also have side effects. A drug or procedure usually use ...

s such as

acne Acne ( ), also known as ''acne vulgaris'', is a long-term Cutaneous condition, skin condition that occurs when Keratinocyte, dead skin cells and Sebum, oil from the skin clog hair follicles. Typical features of the condition include comedo, ...

hirsutism Hirsutism is excessive body hair on parts of the body where hair is normally absent or minimal. The word is from early 17th century: from Latin ''hirsutus'' meaning "hairy". It usually refers to a male pattern of hair growth in a female that ma ...

, and voice changes in women.

Pharmacology

Pharmacodynamics

Mepitiostane is described as similar to

tamoxifen Tamoxifen, sold under the brand name Nolvadex among others, is a selective estrogen receptor modulator used to prevent breast cancer in women and men. It is also being studied for other types of cancer. It has been used for Albright syndrome ...

as an antiestrogen, and through its active form epitiostanol, binds directly to and antagonizes the ER. It is also an AAS.

Pharmacokinetics

Mepitiostane is converted into epitiostanol in the body.

Chemistry

Mepitiostane, also known as epitiostanol 17β-(1-methoxy)cyclopentyl ether, is a

synthetic Synthetic may refer to: Science * Synthetic biology * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic elements, chemical elements that are not naturally found on Earth and therefore have to be created in ...

androstane

steroid A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes t ...

and a

derivative In mathematics, the derivative is a fundamental tool that quantifies the sensitivity to change of a function's output with respect to its input. The derivative of a function of a single variable at a chosen input value, when it exists, is t ...

of DHT. It is the C17β (1-methoxy)cyclopentyl

ether In organic chemistry, ethers are a class of compounds that contain an ether group, a single oxygen atom bonded to two separate carbon atoms, each part of an organyl group (e.g., alkyl or aryl). They have the general formula , where R and R� ...

of epitiostanol, which itself is 2α,3α-epithio-DHT or 2α,3α-epithio-5α-androstan-17β-ol. A related AAS is

methylepitiostanol Methylepitiostanol, known by the nicknames Epistane, Hemapolin, Havoc, and Epi Plex, is a synthetic and orally active anabolic–androgenic steroid (AAS) of the dihydrotestosterone (DHT) group which was first described in the literature in 197 ...

(17α-methylepitiostanol), which is an orally active variant of epitiostanol similarly to mepitiostane, though also has a risk of

hepatotoxicity Hepatotoxicity (from ''hepatic toxicity'') implies chemical-driven liver damage. Drug-induced liver injury (DILI) is a cause of acute and chronic liver disease caused specifically by medications and the most common reason for a drug to be withdr ...

Society and culture

Generic names

''Mepitiostane'' is the generic name of the drug and its and .

References

{{Androgen receptor modulators Androgen ethers Anabolic–androgenic steroids Androstanes Antiestrogens Cyclopentanes Hormonal antineoplastic drugs Prodrugs Episulfides