Allylestrenol for pregnant women

Table of Contents

Allylestrenol is a synthetic steroid with progestational activity. This medication is available throughout Europe, including Russia and many other European countries. It is also available in Japan, Hong Kong, India, Bangladesh, Indonesia, and most Southeast Asia regions, but not in the United States or Canada.

What is Allylestrenol?

Allylestrenol has a structure and function similar to progesterone. Progesterone binds to the progesterone and estrogen receptors. Target cells include the female reproductive tract, the mammary gland, the hypothalamus, and the pituitary.

When bound to the receptor, progesterone will slow the frequency of the release of gonadotropin releasing hormone (GnRH) from the hypothalamus and decrease the luteinizing hormone (LH) surge during pre-ovulation.

In women who have adequate endogenous estrogen, progesterone transforms a proliferative endometrium into a secretory endometrium. Progesterone is essential for the development of decidual tissue and is necessary to increase endometrial receptivity for embryo implantation.

After the embryo is implanted, progesterone serves to maintain the pregnancy. Progesterone also stimulates the growth of alveolar tissue and relaxes uterine smooth muscle. Progesterone has little estrogenic and androgenic activity.

Dosage Considerations

Do not increase or decrease the dose your doctor recommends. Below are the recommended dosage:

Oral medication for women at risk of miscarriage

Adults: 5 mg tid for 5 to 7 days, treatment may increase if necessary. Reduce the dose gradually if symptoms disappear, but be sure you have consulted your doctor.

Oral medication for women at risk of recurrent miscarriage

Adults: 5 mg to 10 mg daily  immediately after pregnancy is confirmed by your doctor. Continue treatment for at least 1 month after the critical period.

Oral medication for women at risk of preterm labor

Adult dose: Maximum consumption is 40 mg per day.

General Guidelines

Here’s how this medication should be used: 

  • Always follow your doctor’s advice and read the information listed on the product package before taking Allylestrenol. Do not increase or lower the dosage without consulting your doctor first.
  • Take it before or after meals. You can take this medication with food or after meals to prevent indigestion.
  • You can drink water to swallow the tablets.
  • It is recommended to take it at the same time every day to get the most benefit of the drug and minimize the risk of side effects after taking Allylestrenol.
  • If, in any case, you miss the schedule for taking your medication as directed by your doctor, take your medication immediately if the interval from your next scheduled medication is not too close. If it is around the time for the next dose, do not take it and do not double the dose.
  • Keep it away from children.
  • Store it at room temperature and do not freeze. Protect medications from exposure to direct sunlight, heat, and moisture. 


The following are several precautions before taking Allylestrenol, including:

  • Allylestrenol is used to prevent miscarriage, maintain pregnancy, and is used to avoid recurrent miscarriages.
  • It is only used for certain pregnancy-related complications, therefore it is not given to breastfeeding mothers.
  • Tell your doctor if you have high-risk factors such as an underactive thyroid, kidney disease, heart disease, or liver disease before taking Allylestrenol.
  • Do not drive a vehicle or use heavy equipment while using it, as it can make you lose your concentration during activities. 
  • No Allylestrenol interactions with food have been reported. You can take it with or without food, but it is preferable to take the medicine as directed by your doctor. 
  • Intake of Phenytoin and Rifampicin lowers the levels of Allylestrenol in the blood, thus it can reduce the medications efficacy.
  • Interactions with Ketoconazole may increase the effectiveness of Allylestrenol.
  • Interact with drugs such as Carbamazepine, Griseofulvin, and Phenobarbital.
  • There is no known interaction between Allylestrenol and alcoholic drinks. 

What is Allylestrenol Used for 

Allylestrenol was designed to be used for miscarriage prevention, prevention of premature labor, and may be used in men for treatment of benign prostatic hyperplasia.

Benign prostatic hyperplasia (BPH) is a common condition as men get older. An enlarged prostate gland can cause uncomfortable urinary symptoms, such as blocking the flow of urine out of the bladder. This condition can also cause bladder, urinary tract, or kidney problems

In general, it has a similar structure to progesterone – which has been given to women who are at risk of recurrent miscarriage and to prevent preterm labor.

In women who are at risk of having miscarriage and progesterone deficiency, the recommended dose of Allylestrenol is 5 mg three times a day, given orally for 5 to 7 days.

Contraindications for Allylestrenol 

There are several conditions where you should not take Allylestrenol to prevent serious side effects. Do not take it if you have an incomplete abortion.

Incomplete abortion is a pregnancy associated with vaginal bleeding, dilatation of the cervical canal, and passage of products of conception. Usually, it has symptoms of severe cramps and heavy vaginal bleeding.

Your doctor will look for evidence of tissue passage in the vagina. Through an ultrasound examination, your doctor can see that some products of conception are still left in the uterus after the abortion.

In addition, do not take Allylestrenol if you are allergic to it. Make sure you tell your doctor about any allergies you have. 

Allylestrenol Drug Interactions

The following are interactions of Allylestrenol with other medications:

May decrease the excretion rate of Allylestrenol (and may cause higher serum levels):

  • Amoxicillin
  • Amphetamines
  • Cefadroxil
  • Cilostazo

May increase the excretion rate of Allylestrenol (and may cause lower serum levels):

  • Benzthiazide (potentially a reduction in efficacy)
  • Amphetamines
  • Cefadroxil

May increase or decrease metabolism of Allylestrenol:

  • Clofazimine, the metabolism of Allylestrenol may increase when combined with Chlorpromazine
  • Dalfampridine, the metabolism of Allylestrenol may lower the excretion rate of Dalfampridin – which may result in higher serum levels.
  • Diazepam, the metabolism of Allylestrenol may be decreased when combined with Diazepam.

There are many other types of drugs that may interact with Allylestrenol. Ask your doctor or pharmacist for further information. 

List of Side Effects 

The most common side effects of Allylestrenol are:

  • Fever
  • Fatigue
  • Headache
  • Menstrual disorders
  • Weight loss/weight gain
  • Widespread swelling occurring all over the body
  • Unwanted hair growth

Make an appointment with your doctor or pharmacist through Smarter Health to find out more about the recommended dosage for allylestrenol. Smarter Health grants you access to healthcare services at home and abroad whenever you need them.

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