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Many people living with migraine try a variety of treatments, including both prescription and over-the-counter (OTC) remedies, to find relief. One medication that sometimes comes up in migraine discussions is diphenhydramine (sold as Benadryl and other brand names), an allergy medicine sometimes used off-label for migraine.
“Yesterday I went to the emergency room for a four-day migraine,” shared one MyMigraineTeam member, who said they were given ketorolac and diphenhydramine. “All better!”
Diphenhydramine is an antihistamine best known for relieving allergy symptoms and causing drowsiness. In some medical settings, it’s part of a “migraine cocktail,” a mix of medications used to treat severe migraine attacks.
You may wonder if diphenhydramine actually helps migraine and if it’s safe to use this way. This article explains how diphenhydramine is used for migraine, what research shows about its effectiveness, and what possible risks you should keep in mind.
Diphenhydramine is an antihistamine — it blocks histamine, a chemical the body releases during allergic reactions. Histamine can cause symptoms like sneezing, itching, watery eyes, and runny nose. Blocking histamine helps reduce these symptoms.
Diphenhydramine is the active ingredient in Benadryl and many brand-name and generic allergy medications. It’s widely available over the counter and comes in several formulations, including tablets, capsules, liquids, and injectable forms used in medical settings. It’s commonly used to treat:
Because diphenhydramine enters the brain, it often causes sleepiness. This effect may be one reason some people feel relief when they take it during a migraine attack.
However, diphenhydramine isn’t approved specifically for migraine treatment. This use is considered off-label, meaning it’s for a purpose different from what the U.S. Food and Drug Administration (FDA) approved. Some medical experts say diphenhydramine has no clear role in migraine treatment.
You might see diphenhydramine used as part of migraine treatment in a few types of settings.
Diphenhydramine is most often used as part of a combination of medications called a migraine cocktail. These mixtures are commonly given in emergency departments to treat severe migraine attacks. The American Migraine Foundation notes that emergency care often uses a mix of medications, rather than just one drug, to treat pain, nausea, and inflammation.
A migraine cocktail may include IV medications such as:
The exact ingredients vary depending on the hospital and the person’s symptoms. One member of MyMigraineTeam shared, “Reglan, Toradol, and Benadryl help decrease the pain.”
Another said, “There is something called a headache concoction. The meds seem to vary, but Benadryl is always in the mix.”
Diphenhydramine is sometimes added to reduce side effects from certain anti-nausea medications. Drugs like metoclopramide and prochlorperazine can cause akathisia, a feeling of intense restlessness or agitation. Antihistamines may help reduce this reaction, but evidence is limited, and some studies show it makes no difference.
Research suggests diphenhydramine may not improve migraine symptoms. One clinical trial found that adding diphenhydramine to metoclopramide did not significantly improve migraine outcomes compared with metoclopramide alone. About 40 percent of participants taking diphenhydramine had lasting relief, compared with 37 percent taking a placebo (inactive treatment). Side effects were also similar in both groups.
Because of this, some researchers and doctors believe diphenhydramine may not improve migraine outcomes and may not be needed in many migraine cocktails.
Although diphenhydramine is typically used in clinical settings for migraine cocktails, some people try it at home during an attack. Since this medication is available over the counter, it may seem like an easy option when other treatments aren’t available.
Some people say it helps them sleep through a migraine attack. Others feel it reduces symptoms like nausea or sinus pressure.
“I had a moderate migraine yesterday,” one MyMigraineTeam member said. “Took two Benadryl at bedtime. Today I am very sleepy from the Benadryl, but no migraine today!”
Another said, “Only a ‘small’ headache today. I took Excedrin and Benadryl, which seemed to help the pressure.”
Others have reported the opposite effect. “I had to take Benadryl for allergies last night and woke up with a migraine,” said one member. “Benadryl tends to give me migraines.”
These mixed experiences highlight that migraine treatments can affect people differently. Talk with your doctor before trying new migraine treatments, even OTC options.
Researchers have explored a few reasons diphenhydramine might affect migraine symptoms.
Histamine isn’t involved only in allergies — it may also play a role in migraine. Some studies show that people with migraine may have higher histamine levels during an attack. Histamine can affect blood vessels and nerve signals in the brain, both of which are involved in migraine.
Because diphenhydramine blocks histamine, some researchers think it may help reduce symptoms in certain cases. However, current evidence doesn’t support antihistamines as a main treatment for migraine.
Diphenhydramine’s sedating effects by blocking histamine may also contribute to relief. Sleep can stop a migraine attack for some people. By making you sleepy, diphenhydramine may help you rest during an attack, which could ease symptoms. However, this doesn’t mean the medication is treating the migraine itself.
Many people with migraine also have seasonal allergies, sensitivity to weather changes, or eczema. These factors can sometimes trigger migraine, possibly due to increased inflammation in the body. Treating these triggers with an antihistamine may seem to help prevent or relieve migraine in some people.
Even though diphenhydramine is available over the counter, it still carries risks and side effects. Common side effects include:
Because it causes sleepiness, diphenhydramine can affect alertness and coordination. Avoid driving or operating machinery after taking it.
Seek urgent care if you have trouble urinating, sudden eye pain or vision changes, or signs of an allergic reaction (such as rash, itching, hives, swelling of the face, lips, tongue, or throat).
Diphenhydramine can interact with several medications used by people with migraine, including:
Combining these medications can increase drowsiness and other side effects. Taking multiple sedating medications together can make side effects stronger.
Diphenhydramine also has anticholinergic properties, meaning it blocks certain nerve signals in the body. These effects can cause side effects like confusion, memory problems, and trouble urinating, especially in older adults. Because of these risks, diphenhydramine generally isn’t recommended for long-term or frequent use unless advised by a healthcare provider.
If you’re considering using diphenhydramine for migraine, talk with your doctor first. They can help determine:
If you try any migraine treatment, including OTC drugs like diphenhydramine, it can help to track your symptoms. Keeping a headache journal can help you and your doctor spot patterns, triggers, and effective treatments. Your headache diary might include:
Over time, this information can help guide decisions about switching treatments or adjusting your plan.
On MyMigraineTeam, people share their experiences with migraine, get advice, and find support from others who understand.
Have you ever tried diphenhydramine for migraine? Let others know in a comment below.
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