Other Fertility Medications

Fertility medications are a required part of the IVF process.  Depending on several factors, each individual is prescribed a specific medication protocol that is best for their individual fertility health. 

Clomiphene citrate (Clomid, Serophene)

Clomid works by blocking the estrogen receptors in your brain, tricking your body into thinking your natural estrogen levels are low.  The pituitary gland then goes into overdrive releasing FSH and LH. This excess FSH and LH will work together to produce follicles and stimulate ovulation.  Clomid is often one of the first steps in fertility treatment, before more extensive treatments like IUI or IVF, are attempted.

Clomid can be prescribed by OB-GYNs before they see a fertility specialist, although reproductive endocrinologists will prescribe Clomid as well.  Clomid is taken orally, about 50mg a day, for several days at the start of the menstrual cycle.  

Letrozole (Femara)  

Although Letrozole is an oral medication that is commonly used in women with breast cancer, it has a place in fertility as well.  Letrozole is an oral medication that induces ovulation. It’s used when women don’t ovulate naturally or have irregular periods. It may also be used to treat unexplained infertility.  Letrozole will be taken once a day for approximately five days. This treatment is often combined with timed intercourse or IUI (intrauterine insemination).  If this treatment does not work, patients often go on to IVF treatment.  

Medications Taken During IVF

The following medications are taken during the in vitro fertilization (IVF) process.


Gonadotropin medications mimic the FSH (follicle-stimulating hormone) and LH (luteinizing hormone) that naturally occur in your body.  The brand names for each are:

FSH: Follistim or Gonal-F

HMG (a combination of FSH and HCG driven LH activity): Menopur 

The goal of gonadotropins is to stimulate the ovaries and produce multiple follicles (eggs). These hormones will be injected for 7 – 12 days during the phase called ovarian stimulation.  The patient will give themselves these injections subcutaneously in the mid-section. It’s likely these dosages will be adjusted during the stimulation phases based on increasing estrogen levels and follicle sizes. 

Agonist or Antagonist

You will likely be prescribed an agonist or antagonist during IVF stimulation.  Both of these medications suppress your natural hormones, so they do not interfere with prescribed hormones.  The antagonist and agonist have different mechanisms of action, but achieve the same goal of hormone suppression. 

An antagonist reacts immediately and is a blocker that works on your pituitary gland.  This causes all hormones to be immediately suppressed. If you are prescribed an antagonist (Ganirelix or Cetrorelix/Cetrotide) you will begin taking a daily injection around day 4 – 6 of stimulation.  

If you are prescribed an agonist (Lupron) you will begin daily injections a few weeks before you start your hormones.  Upon initial injection of Lupron, your estrogen will increase. Then, over the following few days, estrogen will decrease until it’s close to 0. Both medications are similar in efficacy and your provider will prescribe one based on your specific protocol.  These injections are also given subcutaneously. 

Trigger Shots

A trigger shot is used at the end of stimulation to signal ovulation.  This will tell the body it’s time to release the eggs from the follicles so they can be retrieved easily.  This shot is very important and the timing is critical. Your nurse will be in close contact with you as to when this must be administered during the end of the stimulation period.  The trigger shots consist of HCG, which is structurally similar to LH. LH is the hormone that triggers ovulation in a natural cycle and completes egg maturation.  


As you prepare for a transfer of the embryo, a medication called progesterone will be prescribed.  This medication supports the endometrial lining so the embryo can easily attach and implant. If pregnancy occurs, the placenta will take over and begin releasing progesterone to not only sustain the lining but further develop the fetus.   Progesterone can be administered through intramuscular injections or inserted vaginally (Prometrium, Crinone,Endometrin). You will likely remain on progesterone until 10 weeks gestation. Your provider will individualize dosages based on your specific needs. 

It’s best to consult with your provider at Dallas Fort-Worth Fertility Associates about the medications, dosing, and timing that is right for you.  Please contact us with any questions about fertility medications. 

About the Author: 

Samuel Chantilis, M.D. is a highly trained and experienced infertility specialist in his hometown of Dallas, TX. He is board certified in reproductive endocrinology and infertility, and has been practicing in Texas since completing his training in 1993.  Dr. Chantilis was a faculty member at UT Southwestern Medical School for five and a half years before entering private practice in January 1999 at Presbyterian Hospital in Dallas. Dr. Chantilis has been the leading provider of IVF services at the Presbyterian Hospital ARTS program since 1999, having conducted approximately 2,500 egg retrievals