The drug levothyroxine (Synthroid, Levoxyl, others) has long been the treatment
for sluggish thyroids or hypothyroidism. The pill needs time to be absorbed
properly, so patients are often instructed to take it daily a half hour
to an hour before breakfast. But that can make the regimen inconvenient
for some, and compliance declines.
Now, a new study suggests that weekly doses appear to work as well. Indian
researchers presented the findings at the 2016 annual meeting of the American
Association of Clinical Endocrinologists in Orlando. "Once weekly
L-thyroxine replacement was well tolerated and there was no indication
of acute toxicity or hypothyroidism symptoms compared with daily therapy,"
according to researchers Satish Wasoori, MD, and Manoj Naik, MD, of Park
Hospital in Guragaon, India. The
new study echoes some findings from previous research.
U.S. endocrinologists who reviewed the findings say, in general, they still
prefer daily dosing.
In the new research, the doctors evaluated 40 women, ages 25 to 55, who
had been diagnosed with
hypothyroidism for at least five years and were on a daily dose of levothyroxine. They
assigned them to two groups. One group had thyroid-stimulating hormone
(TSH) levels viewed as in the normal range at the start; the other group
had levels that were above the normal range. Higher TSH levels indicate
a failing thyroid, according to the American Thyroid Association.
Both groups of women took a weekly dose of
levothyroxine seven times their daily dose, following the regimen for six months. Those
in group 1, with TSH levels closer to ideal to start with, all maintained
normal thyroid functioning by 12 weeks into the study and maintained it
at the six-month mark. In group 2, 16 of 20 had normal functioning at
12 weeks and 18 did by the six-month mark. Two did not achieve normal
thyroid function, probably due to underlying diabetes and obesity, the
The researchers say the weekly regimen is effective and safe, ''making
it a possible alternative to customary daily therapy." They also
concluded that the once-a-week regimen ''can be considered as
first-line therapy in working young and middle-aged women facing impaired
absorption due to early breakfast." They would need to take the weekly
dose on an empty stomach, but could skip that waiting period the other six days.
Not everyone is on board with that idea. "There is no question that
daily therapy is preferable to weekly therapy," says Jacqueline Jonklaas,
MD, associate professor of endocrinology at Georgetown University Medical
Center, Washington, D.C. She reviewed the new data.
Why? "The 'half life' of thyroid hormone (how long it stays
in your system) means that if you give it daily there are minimal peaks
and troughs (ups and downs) in its blood level," she says. "However,
if you give a larger dose on a weekly basis there are big peaks and troughs.
This means that a patient may have symptoms of too much thyroid hormone
right after the dose is given and symptoms of too little right before
the next dose is due to be given. This is not at all ideal. The high levels
could potentially be associated with risks such as a fast or irregular
In her view, "the only patient who might be considered for weekly
therapy is someone who could not be kept with normal thyroid levels on
daily therapy." That's usually due to failing to take the medicine
daily, she says. "Therefore, weekly therapy would only be a compromise
when normal levels just cannot be achieved with daily therapy."
The suggestion to consider weekly dosing a ''first-line''
therapy for some is a bit aggressive, agrees Daniel Nadeau, MD, the Dr.
Kris V. Iyer endowed chair in diabetes care and program director of the
Mary & Dick Allen Diabetes Center at Hoag Hospital, Newport Beach,
Ca. He reviewed the findings.
Instead, he says, "I think once weekly is an option when there is
an individual who for whatever reason can't use daily dosing."
If someone is on a weekly dose, he says, he would recommend waiting a
full hour before eating.
Multiple studies dating back several years have looked at weekly dosing,
says Matthew Freeby, MD, director of the UCLA Diabetes Center of Santa
Monica and assistant clinical professor of medicine at the David Geffen
UCLA School of Medicine. While research in general has found patients
do fine, he says he would not recommend it for those with heart disease.
Remembering the daily dose is easier, Dr. Nadeau says, if patients keep
the medication at their bedside. "As soon as they wake up, take it,"
he says. Then, they can go about their morning routine for a few minutes
before eating breakfast, while the medication is absorbed, he says.
Most do not have an issue remembering the daily dose, says Dr. Jonklaas
says, adding that medicine can be taken morning or evening. "Patients
can put their thyroid hormone on their night stand, next to their tooth
brush, use a weekly pill container, set an i-phone alarm and so on,"
she says. "I think working on finding a schedule that someone can
keep to would be far preferable to pursuing weekly therapy. I also worry
that this is not ideal for women of child-bearing potential. I do not
think the up and downs in thyroid hormone would be optimum during pregnancy."
If the problem is an absorption issue, she says, that can be remedied by
using liquid thyroid medicine or treated whatever is causing the poor
Current guidelines issued in 2014 by the American Thyroid Association say
weekly dosing can be considered if a patient has compliance issues.