In the days leading up to Lauren Herrod’s period, brain fog, fatigue and depression made simple tasks like preparing lunch for her young daughter or going to the gym feel impossible — “like trying to live and move through cement,” she said. Last month, her doctor diagnosed her with premenstrual dysphoric disorder, or P.M.D.D., an often debilitating form of premenstrual syndrome.
But on the first day of a recent luteal phase, she felt clearheaded and energized in a way she hadn’t before. It was “like somebody pressed a button,” she said excitedly in a video she posted to TikTok.
What had changed? She had taken two over-the-counter drugs: Allegra and Pepcid AC.
Ms. Herrod, 31, is one of many people who say on social media that taking two antihistamines — often Pepcid AC along with Allegra or Zyrtec — has eased symptoms associated with health conditions like P.M.D.D., perimenopause and menopause. Some of these women, including Ms. Herrod, say they have struggled to get doctors to take their symptoms seriously. “People who are trying the Allegra-Pepcid combination are not taking it to lose 15 pounds,” said Dr. Tracy Shevell, an OB-GYN in New York who has posted online about the trend. “Their quality of life is desperately affected.”
Experts cautioned against taking antihistamines long-term without a doctor’s input. But they acknowledged that the relief some people are feeling from these medications is real.
What are antihistamines?
Antihistamines are drugs typically used to ease minor allergic reactions that happen when immune cells release an inflammatory chemical called histamine. The most common ones, including Allegra, Zyrtec and Claritin, are known as H1 antihistamines because they target the H1 histamine receptors found on cells throughout the body.
Pepcid AC is an H2 antihistamine. Primarily used to treat digestive problems, it contains famotidine, which blocks histamine receptors in the stomach and temporarily prevents the production of more stomach acid.
Why might these drugs help?
Histamine is closely linked to female sex hormones like estrogen, said Dr. Melinda Ring, an internist who leads the Osher Center for Integrative Health at Northwestern University. Mast cells — immune cells that set off allergic reactions — have receptors for estrogen. When estrogen binds to those cells, it can cause them to release inflammatory chemicals like histamine.
The release of histamine can, in turn, stimulate the ovaries to produce more estrogen. “It’s a loop,” she said.
In perimenopause, estrogen swings wildly, Dr. Ring said. At the same time, progesterone, a hormone that acts as a calming agent for histamine, falls. “The theory that’s driving this trend is that these unpredictable estrogen spikes could trigger this,” she said.
Histamine causes inflammation, which may worsen pain and cramping, said Dr. Taz Bhatia, an integrative physician who treats women’s health issues, among other concerns, at her practice in Atlanta.
For some people, taking antihistamines could temporarily ease symptoms, said Dr. Bhatia.
Histamine can also cause brain fog, a key symptom of P.M.D.D. and menopause, Dr. Bhatia said. It’s possible that reducing histamine levels throughout the body could provide some relief.
These drugs might help temporarily, but they can’t treat the root causes of a person’s symptoms, which may include fluctuating hormone levels, yeast overgrowth or even allergies, experts said.
What does the research show?
There are no clinical trials on the use of antihistamines for any of these conditions. While there is reason to believe the drugs might be beneficial, experts say it’s also possible that people who report improvement in their symptoms may be experiencing a placebo effect. (This has been shown in studies of some histamine-related concerns.)
Other treatments have been clinically proven to help with these conditions. In randomized controlled trials, people who took antidepressant drugs known as S.S.R.I.s., either daily, in the two weeks before periods or at the onset of symptoms, had reduced P.M.D.D. symptoms. And hormone therapy has been shown to improve symptoms of perimenopause and menopause like hot flashes and brain fog.
Some on social media have also discussed supplements such as quercetin, which acts as a natural antihistamine, and vitamin C, which has been shown to have anti-inflammatory properties. But none of these have been clinically tested in relation to these conditions.
Is it safe?
“Antihistamines by themselves are not bad,” said Dr. Bhatia. But using them long-term carries risks.
Overuse of H1 antihistamines can dry out the mouth and nasal passages, Dr. Bhatia said, potentially increasing the risk of sinus infections. “You’re drying up mucus rather than letting things drain naturally,” she said. Recent research has found that frequent use of some H1 antihistamines, notably Benadryl, increases the risk of dementia, Dr. Shevell said.
H2 antihistamines reduce the production of stomach acid, which your body needs to absorb essential nutrients like B12, iron, zinc and calcium from food. Women may already struggle to get enough of those nutrients as they age, because acid levels in the stomach decline, Dr. Ring said.
Dr. Bhatia said anyone concerned about their symptoms should talk to their doctor.
But, she added, it’s also important to trust your own assessment of how you’re feeling. “Only you know you,” she said.
Chloe W. Shakin is a social media editor for The Times, based in London.
The post Why Women Are Trying Allergy Drugs for Period and Perimenopause Relief appeared first on New York Times.
