Written by 11:46 am Prescription Drugs

Diclegis – She’s Back (after 30 years)

This is a story of survival.  A story of recovery.  A story of courage to overcome obstacles and fear.  A story of patience, fortitude, longing and finally…victory.  It has, it would seem, all the makings of a Hollywood film.  This is the story of Diclegis.  

Okay.  That may be a bit over-the-top when it comes to introducing a newly approved drug.  But the Diclegis (pronounced dye-CLEE-gis)  story is a good one none the less.  Read on and let me tell you about it.

On April 8, 2013 the FDA gave it’s nod of approval to the only prescription medication specifically indicated for the treatment of nausea and vomiting in pregnancy (NVP) – Diclegis (doxylamine/pyridoxine) tablets.  Actual market availability is expected in June of this year.


The real story behind the U.S. approval of Diclegis is important, as there is likely to be some misunderstanding in the public about this drug.  You see, 30 years ago there was this drug.  Let’s call him Benny (his real name was Bendectin).  Benny was born in 1956, contained the same ingredients as Diclegis, and helped pregnant women with nausea and vomiting.  But one day Benny was in the wrong place at the wrong time.  In the last 1970’s and early 1980’s numerous lawsuits began to arise claiming that Benny caused birth defects.  Studies were conducted, and no connection could be found between these birth defects and Benny.  Nevertheless, the costs associated with defending Benny were too much for Merrel Dow Pharmaceuticals.  They put Benny down in 1983. 

Duchesnay relates the information this way:

“Thirty years ago, most large pharmaceutical manufacturers in the U.S. were deserting the field of maternal-fetal medicine. At the time, numerous lawsuits alleged that birth defects resulted from the use of medications for conditions like NVP. The lawsuits were ultimately dismissed and claims shown to be unsubstantiated – but the impact on the medical field is still felt today. Drugs deemed to be safe and effective such as Bendectin were withdrawn from the U.S. market and research projects were halted. For more than 30 years now, expectant mothers in the US have been deprived of safe and effective treatments to help manage a number of conditions occurring during their pregnancies, including NVP.”


The truth, however, is that Bendectin never caused those birth defects, and has continued to be used in Canada (trade name Diclectin) without any concerns for the past 30 years.  In a quote from Duchesnay’s website: “The Canadian Ministry of Health reports not a single safety concern associated with the product during the past 30 years.”  The cases against Bendectin and Merrell Dow in the U.S. were all found to be groundless.  In fact, the most outspoken “expert” witness against Bendectin, Australian physician  Dr. William McBride, “was convicted of scientific fraud and ultimately struck in 1993 from the Australian Register of medical practitioners for deliberately falsifying data.”  Sad but true. 


And so today, thanks to the persistence of Duchesnay Pharmaceuticals, pregnant women in the U.S.  have access to a commercially available prescription drug for NVP.  Diclegis is a combination delayed-release tablet containing 10mg of doxylamine succinate (an antihistamine) and 10mg pyridoxine hydrochloride (fancy name for a form of Vitamin B6).

The recommended dosage for Diclegis is posted below:

From Diclegis Prescribing Information

The Ingredients:

DoxylamineA very sedating antihistamine sold over the counter in the U.S. to treat insomnia under the brand name Unisom as a 25mg tablet.  It is also included in the cough/cold product Nyquil.  This ingredient is considered Class A with respect to pregnancy, meaning it is considered completely safe for pregnant women to use in recommended dosages.

Pyridoxine: Also known as Vitamin B6 (one form of B6).  This is a water soluble vitamin which is involved in many essential body functions.  Dietary sources include fish, potatoes, grains and nuts. 


I’m happy to see Diclegis approved and available in the U.S. for the treatment of NVP.  There are plenty of GOOD reasons to pull prescription drugs off the market.  But the reasons that led to the removal of these ingredients from the U.S. were simply bad science.

BUT…that said, from a marketing perspective, Duchesnay has a big hill to climb.  It is likely to be quite expensive.  Zofran (ondansetron), though not technically indicated for NVP, is widely used and considered low-risk (category B) for pregnancy and is available generically now.  [NOTE:  An interesting perspective on the use of ondansetron for NVP is provided by a Canadian MD, who points out that there may be some risks that should be considered] 

Coverage for Diclegis by insurance companies is likely to be minimal for some time.  Finally, the availability of these ingredients in OTC products is likely to at least tempt some folks to make their own version of Diclegis without the prescription hassle (no, I’m not recommending this).  The word is that they have reached out to Publicis Selling Solutions to build their sales force and launch this product.  To those brave Reps that take on this challenge, I wish you the best.

Patients wishing to know a little more can read about Diclegis on the PATIENT INFORMATION sheet provided by the manufacturer.

So…she’s back.  And after 30 years of morning sickness pregnant women in the U.S. have an approved product that is both safe and effective. 

Last modified: April 17, 2023