The Misconception of a Global Ban
Dydrogesterone, a synthetic progestogen often marketed as Duphaston, has been used clinically since 1961 and is approved in over 100 countries. However, its unavailability in certain Western countries, including the United States, has led to a misunderstanding that the drug was globally discontinued or banned for safety reasons. The reality is that the reasons for its withdrawal from these markets are primarily commercial and economic. The U.S. Food and Drug Administration (FDA) has confirmed that dydrogesterone was not withdrawn due to safety or effectiveness concerns.
What is Dydrogesterone?
Dydrogesterone is an orally active, synthetic form of progesterone. Its unique 'retro-progesterone' structure contributes to its high bioavailability and specific action on progesterone receptors, allowing for efficacy at lower oral doses. Unlike some other synthetic progestogens, it generally does not inhibit ovulation and lacks androgenic effects.
Primary Clinical Applications
Dydrogesterone is used to treat various conditions resulting from progesterone deficiency, including:
- Menstrual disorders, such as irregular cycles, painful periods, and PMS.
- Endometriosis, providing pain relief without inhibiting ovulation, which can be helpful for those who wish to conceive.
- Infertility and pregnancy support, utilized for luteal support in ART and to potentially prevent threatened or recurrent miscarriages in cases of confirmed progesterone insufficiency.
- Hormone replacement therapy (HRT) in combination with estrogen for postmenopausal women with a uterus to protect against endometrial hyperplasia.
The Real Reason for Discontinuation in the US, UK, and Australia
The decision to withdraw dydrogesterone from these significant markets was a commercial one by the manufacturers.
- United States: The drug was initially registered in 1961. The license holder, Solvay, withdrew the product in 1997 because the registered uses were no longer seen as commercially viable. The FDA officially stated in 2017 that this withdrawal was not due to safety or effectiveness issues, which means other companies could potentially seek approval for generic versions.
- United Kingdom and Australia: The drug was withdrawn from the UK in 2008 and Australia in 2011. The reasons given included low sales of a relatively inexpensive drug and insufficient new, commercially appealing indications to justify continued marketing.
Comparison of Progestogen Options
In countries where dydrogesterone is not available, alternatives like micronized progesterone are used. Here is a comparison:
| Feature | Dydrogesterone | Micronized Vaginal Progesterone (MVP) |
|---|---|---|
| Administration | Oral tablets | Vaginal capsules, gels, or suppositories |
| Bioavailability | High oral bioavailability | Bypasses liver, high uterine concentration, variable systemic absorption |
| Patient Convenience | Generally considered more convenient | Can cause local irritation, discharge, potentially less convenient |
| Efficacy in ART | Studies suggest similar or higher live birth rates compared to MVP for luteal support | Standard for luteal support, but absorption varies |
| Side Effects | Headache, nausea, breast tenderness, menstrual irregularities | Vaginal irritation, bleeding, drowsiness |
Conclusion
The idea that dydrogesterone was discontinued because it was unsafe is incorrect. Its withdrawal from certain countries was a result of market forces, including low sales and changing commercial priorities. It remains a widely used and effective treatment for progesterone deficiencies in over 100 countries, supported by a long history of use and affirmation of its safety profile by regulatory bodies like the FDA. Understanding the difference between a commercial withdrawal and a safety-related recall is key to understanding the status of this medication.
For more authoritative information on drug regulatory status, consult government health agency websites. An example of a determination notice can be found at the U.S. Federal Register.
