Alberta doctor fears for pregnant patients as supplies of key thyroid medication dwindle

Concerns are growing about a nationwide shortage of a drug to treat thyroid problems, which doctors say could put the health of thousands of Canadian patients — including pregnant women — at risk

Propylthiouracil (PTU) is used to treat people with hyperthyroidism (overactive thyroid) who can't take the first-line medication because they are pregnant, trying to conceive or have a drug allergy.

According to the Canadian Society of Endocrinology and Metabolism, PTU is the preferred treatment for women who are in their first trimester of pregnancy because it has a lower risk of congenital abnormalities compared with the standard — and only alternative — medication, methimazole.

The society says 36,000 prescriptions were written for PTU in Canada in 2018.

Production of the drug was stopped in December. Canada's only supplier, Paladin Labs Inc., cited "manufacturing issues" as the reason for the discontinuation with Drug Shortages Canada, a database where drug sellers are required to report production issues.

"This, of course, was a concern because without this medication we would be putting people — especially pregnant women with an overactive thyroid condition called Graves' disease — at risk," said Dr. Lois Donovan.

She's a Calgary endocrinologist who specializes in treating pregnant women with thyroid problems and diabetes. Donovan is also a clinical professor in the Cumming School of Medicine at the University of Calgary.

"It leaves patients in a situation where they're choosing between two or three bad options, and as their health-care provider, I want to do everything I can to help them," she said.

According to Donovan, those options include: reverting to the first-line drug, which has a higher risk of congenital abnormalities; stopping treatment altogether, which increases the risk of complications such as miscarriage; or performing surgery, which can also be risky during pregnancy.

Patient worries

"It's been frustrating," said one of Donovan's patients — a Calgary woman who is six weeks pregnant and has an overactive thyroid, causing symptoms including fatigue and an increased heart rate. CBC News has agreed to keep her name confidential because she has not yet made her pregnancy or her health condition public.

She ran out of her PTU earlier this week, and her condition has gone untreated as a result.

"Putting me under other medication is really not the best option. So it's worrisome for everybody," she said.

"It's pretty overwhelming knowing that this medication that can be used isn't available."

Doctors' group calls on Health Canada for help

"Most patients don't have an alternative, that's really the message. The reason they ended up with PTU is because that's the only alternative," said Dr. Stan Van Uum, president-elect of the Canadian Society of Endocrinology and Metabolism and professor at Western University in London, Ont.

He estimates up to 10,000 Canadians could be impacted by the shortage.

The society sent a letter to federal Health Minister Patti Hajdu on April 29, describing its "grave concerns" about the discontinuation of PTU.

 "This is a major priority for patients, for patient care, for patient safety," said Van Uum.

"We need to work on access through importing and getting manufacturers to either produce here or put it on the market in Canada and … that process has to be expedited."

Serious shortage

Health Canada posted PTU to its list of Tier 3 drug shortages on May 25.

Tier 3 shortages are defined as those that have the greatest potential impact on Canada's drug supply and health-care system.

"Health Canada is aware that there have been localized reports of patients having difficulties accessing this medication," a spokesperson said in a statement emailed to CBC News.

"The department is actively managing this shortage and is working with provinces, territories, companies and stakeholders, including the Canadian Society of Endocrinology and Metabolism, to explore mitigation options, including the possibility of accessing foreign supply."

According to Health Canada, PTU may be requested by physicians through its Special Access Program (SAP), which may grant emergency access to non-authorized drugs from a foreign manufacturer for a patient with "a serious or life-threatening condition where conventional therapies have failed, are unsuitable or unavailable."

Paladin Inc. responded to CBC's inquiries about the discontinuation of PTU with a brief emailed statement: "The product was manufactured by a partner who stopped production, and we do not have another option available. The discontinuation was not due to safety or efficacy concerns."

Meanwhile, Donovan has been in talks with Health Canada and is scouring the country trying to find a supply of PTU for her patient, who has gone without treatment for two weeks.

"For me, the main thing is writing the prescription and getting the drug for the patient and making sure that she gets it in a timely fashion," she said.

"We're hoping going forward … we're not in a situation again where a company decides they're not going to make a medication that we need without being informed well in advance."