# Estradiol benzoate/testosterone isobutyrate

Estradiol benzoate/testosterone isobutyrate (EB/TiB), sold under the brand names Femandren M and Folivirin, is an injectable combination medication of estradiol benzoate (EB), an estrogen, and testosterone isobutyrate (TiB), an androgen/anabolic steroid, which is used in menopausal hormone therapy for women. It is provided in the form of 1 mL ampoules containing 2.5 mg estradiol benzoate and 25 mg testosterone isobutyrate in a microcrystalline aqueous suspension and is administered by intramuscular injection once every 4 to 6 weeks. EB/TiB reportedly has a duration of about 14 to 21 days.
The medication is available only in the Czech Republic and Slovakia. EB/TiB was originally developed and marketed by the Swiss pharmaceutical company Ciba and was introduced for medical use by 1953, following the development of testosterone isobutyrate in 1952. It was intermittently manufactured by Spofa and then Biotika and is now manufactured by BB Pharma.
The effect of EB/TiB on gonadotropin levels in postmenopausal women have been studied.
An oral tablet product with the same brand name of Femandren, containing ethinylestradiol and methyltestosterone, was marketed around the same time as Femandren M, and should not be confused with the injectable formulation.
vte Androgen replacement therapy formulations and dosages used in women :
| Route | Medication | Major brand names | Form | Dosage |
| Oral | Testosterone undecanoate | Andriol, Jatenzo | Capsule | 40–80 mg 1x/1–2 days |
| Oral | Methyltestosterone | Metandren, Estratest | Tablet | 0.5–10 mg/day |
| Oral | Fluoxymesterone | Halotestin | Tablet | 1–2.5 mg 1x/1–2 days |
| Oral | Normethandrone$^a$ | Ginecoside | Tablet | 5 mg/day |
| Oral | Tibolone | Livial | Tablet | 1.25–2.5 mg/day |
| Oral | Prasterone (DHEA)$^b$ | – | Tablet | 10–100 mg/day |
| Sublingual | Methyltestosterone | Metandren | Tablet | 0.25 mg/day |
| Transdermal | Testosterone | Intrinsa | Patch | 150–300 μg/day |
| Transdermal | Testosterone | AndroGel | Gel, cream | 1–10 mg/day |
| Vaginal | Prasterone (DHEA) | Intrarosa | Insert | 6.5 mg/day |
| Injection | Testosterone propionate$^a$ | Testoviron | Oil solution | 25 mg 1x/1–2 weeks |
| Injection | Testosterone enanthate | Delatestryl, Primodian Depot | Oil solution | 25–100 mg 1x/4–6 weeks |
| Injection | Testosterone cypionate | Depo-Testosterone, Depo-Testadiol | Oil solution | 25–100 mg 1x/4–6 weeks |
| Injection | Testosterone isobutyrate$^a$ | Femandren M, Folivirin | Aqueous suspension | 25–50 mg 1x/4–6 weeks |
| Injection | Mixed testosterone esters | Climacteron$^a$ | Oil solution | 150 mg 1x/4–8 weeks |
| Injection | Mixed testosterone esters | Omnadren, Sustanon | Oil solution | 50–100 mg 1x/4–6 weeks |
| Injection | Nandrolone decanoate | Deca-Durabolin | Oil solution | 25–50 mg 1x/6–12 weeks |
| Injection | Prasterone enanthate$^a$ | Gynodian Depot | Oil solution | 200 mg 1x/4–6 weeks |
| Implant | Testosterone | Testopel | Pellet | 50–100 mg 1x/3–6 months |
| Notes: Premenopausal women produce about 230 ± 70 μg testosterone per day (6.4 ± 2.0 mg testosterone per 4 weeks), with a range of 130 to 330 μg per day (3.6–9.2 mg per 4 weeks). Footnotes: $^a$ = Mostly discontinued or unavailable. $^b$ = Over-the-counter. Sources: See template. |||||