Canadian family doctors have been told to reconsider Diclectin as the go-to drug treatment for morning sickness after new research raised concerns about whether the medication is any better than a commonly available vitamin.

In a strongly worded commentary, the Canadian Family Physician medical journal said it no longer recommends the popular medication as the first-line treatment, citing the work of a Toronto doctor whose research has exposed flaws in the evidence supporting Diclectin’s efficacy.

The commentary is a renouncement of the journal’s previous publication of clinical guidelines advocating the drug’s use, which the journal says were developed by Sick Kids’ embattled Motherisk program, which had financial ties to the drug company that makes Diclectin.

The medical journal said it ended its longstanding relationship with Motherisk in part because of concerns about its independence from the drug company — yet another black eye for the once-prestigious program engulfed in scandal for faulty hair testing for drugs and alcohol in its now-shuttered lab.

“Evidence is not static; re-evaluation of accepted truths should not be seen as a weakness as new information comes forward,” the authors, who include the journal’s scientific editor and the chair of the editorial advisory board, wrote in the January edition.

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The authors said the past guidelines’ recommendation of Diclectin as the go-to drug treatment “is not supported by the current best evidence.” The commentary also said Toronto doctor Nav Persaud’s recent “systematic re-evaluation of the evidence” revealed that the combination of doxylamine and vitamin B6 is “not superior in efficacy” to vitamin B6 alone.

The commentary is part mea culpa as the authors said the journal did not subject Motherisk articles to “a full double-blind peer-review process. This was based on assumptions about the quality of the work and the integrity of the organization.”

Going forward, the authors said the journal will only work with institutions or organizations that “do not have any ties to industry or other entities that would create, or even appear to create, information or guidelines that have a purpose other than clear and science-based benefit to patients.”

The journal is published monthly by the College of Family Physicians of Canada, though it has full editorial independence. The journal’s target audience is family physicians nationwide and has a print circulation of about 32,000.

The new Canadian Family Physician commentary focuses on the drug’s efficacy, not safety.

Diclectin is a combination of an antihistamine and vitamin B6. Research has shown one prescription is filled for every two live births in Canada.

Branded Diclegis in the U.S., the drug has been recommended by various expert groups in North America as a first-line drug treatment for nausea and vomiting in pregnancy.

Canadian Family Physician said doctors could consider vitamin B6 alone as a first-line therapy.

“The routine practice was to offer Diclectin to all women who came in seeking treatment for nausea and vomiting during pregnancy,” said Persaud, who has extensively researched studies supporting the drug’s use. “So this new recommendation from Canadian Family Physician is a marked departure from current practice.”

The journal’s new stance credits the work of Persaud, who recently co-authored a research article that found “questionable data integrity, high dropout rate, and other methodological concerns” with a 1975 clinical trial that regulators have cited as proof of the drug’s efficacy.

Persaud’s research also found a 1997 study affiliated with Motherisk — a “meta-analysis” of 24 individual studies — inaccurately suggested the antihistamine in Diclectin could actually reduce the chance of birth defects.

“Pregnant women might be disappointed to learn that a study underlying the previous recommendation for this medication was flawed and inaccurate. This has now been confirmed by the journal that published the original guidelines,” Persaud said.

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Health Canada conducted a review of the drug in 2016 and found its benefits continue to outweigh its risks.

In December, the Society of Obstetricians and Gynaecologists of Canada released new guidelines on treating morning sickness, updating those that Motherisk helped develop more than a decade earlier.

The updated guidelines recommend Diclectin or vitamin B6 alone as the first-line drug when dietary or lifestyle changes have not worked.

The society’s CEO, Dr. Jennifer Blake, said her group disagrees with the journal’s new recommendation “based on evidence and research to the contrary.”

“It would be a pity if women were made to be concerned about a medication that has been used by thousands of women over decades and is proven to be safe and effective,” she added.

Blake said Duchesnay, the maker of Diclectin, is a sponsor of the society but emphasized that the company “did not give us any money in support of this guideline.” She said the organization accepts money from drug companies if it is unrestricted.

In statements to the Star, Duchesnay’s spokesman said it is common practice for drug companies to financially support medical groups and, when doing so, Duchesnay “follows ethical pharmaceutical practices.”

He said Diclectin’s effectiveness has been proven through numerous studies.

A Sick Kids spokesperson said the hospital implemented a new conflict-of-interest policy after questions were raised about Duchesnay’s funding for Motherisk programs and research.

The new policy ensures the hospital “takes into consideration health sector best practices as they relate to disclosure and management of conflicts of interest,” Gwen Burrows said.

Sick Kids no longer receives funding from Duchesnay, she said.

The Motherisk program came under fire in late 2014 after the Star exposed concerns about the reliability of its drug and alcohol hair tests, which were used in thousands of child protection cases and were often accepted without question as proof of parental substance abuse.

Sick Kids shuttered the lab and issued a public apology in 2015 for “unacceptable” practices after completing an internal probe. But the hospital has continued to house Motherisk and support its other functions, which include popular helplines for expectant and lactating women and their doctors.

The call centre responds to 30,000 calls per year, according to 2015 statistics on Motherisk’s website, which describes the advice it provides as “scientific” and “evidence-based.”