Why Do Antihistamines Make You Drowsy
16 December 2013
Drowsiness is one of the major side effects of some antihistamines, such as diphenhydramine and doxylamine succinate . And because of their powerful sedating qualities, antihistamines are also the active ingredients found in numerous over-the-counter sleep aids.
But why do antihistamines make you sleepy?
The story begins with histamines, which are chemical compounds that play a couple of roles in the body, though they’re best known for their involvement in the body’s local immune responses.
When you get injured or your immune system detects a potentially dangerous foreign substance, certain white blood cells and tissue cells release histamines that seek out and attach to other cells that have a histamine receptor.
Here, the histamines induce an inflammatory response they dilate the blood vessels, increasing blood flow to the site of injury or invasion. They also make blood vessels more permeable, allowing proteins and white blood cells to seep into the damaged or infected tissue.
But there are side effects to this healing process. For example, when you’re fighting a cold , histamines widen the blood vessels in your nasal cavity, causing nasal congestion.
Additionally, the increased fluid leakage from your blood vessels, combined with an increased mucous production also caused by histamines can result in a runny nose.
Congestion Can Cause Brain Fog
A stuffy, swollen nose can make it difficult to think clearly, often causing a hazy or tried feeling. Many have termed this feeling brain fog, and it results from the congestion and pressure in your nasal and sinus air passages. Without treating allergy symptoms, and sometimes contributing sinus issues, the inflammation, irritation, and runny nose at the root of this issue will keep making you feel foggy.
What Should I Avoid While Taking Allergy Relief
Allergy Relief may cause blurred vision or impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.
Drinking alcohol can increase certain side effects of chlorpheniramine.
Ask a doctor or pharmacist before using any other cold, cough, allergy, or sleep medicine. Antihistamines are contained in many combination medicines. Taking certain products together can cause you to get too much of a certain drug. Check the label to see if a medicine contains an antihistamine.
Avoid becoming overheated or dehydrated during exercise and in hot weather. Allergy Relief can decrease sweating and you may be more prone to heat stroke.
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How Long Do My Allergy Symptoms Last
Hay fever, or allergic rhinitis, is caused by environmental allergens like pollen in the air. Symptoms include itching, sneezing, runny nose, and watery eyes. Depending on how long these symptoms last, certain allergy medications may work better than others.
Here are the three most common kinds of medications people use.
Is Benadryl Drowsy Or Non
Drowsiness is the main side effect of Benadryl and a common side effect in all first-generation antihistamines. Diphenhydramine is the active ingredient in Benadryl as well as OTC sleep aids.
While there isnt a non-drowsy Benadryl product available, there are non-sedating antihistamines, such as Zyrtec or Allegra. Restlessness is one side effect of Zyrtec, though, so it may not be the best option to take before bedtime.
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Things You Should Know Aboutallergy
- 09 Jul, 2020
Allergies can cause all kinds ofunpleasant, distracting symptoms, from digestive upsets and headachesto respiratory trouble and runny eyes. However, you may also haveexperienced another few hallmark symptoms of allergy problems:fatigue, drowsiness, and mental sluggishness.
If you have had noticeable troublegathering your thoughts, maintaining your alertness, or even stayingawake during the day, you need to understand how your allergies maycreate or aggravate your tiredness. Take heed of the following fourkey points about allergy-related fatigue.
1. Allergens Cause BiochemicallyBased Fatigue
An allergic reaction occurs when yourimmune system goes into battle by mistake, attacking a harmlesssubstance as if it were a virus or other germ. It does this byinstructing mast cells to produce antibodies for release into thebloodstream. These antibodies belong to a category known asimmunoglobulin E.
In addition to immunoglobulin E, theimmune system releases a substance called histamine. When both ofthese substances produce an inflammatory reaction in the body, youmay experience a sense of tiredness alongside other, more obviousallergic symptoms.
2. Allergic Sinusitis Can CauseBrain Fog
Individuals who feel dazed and unableto think well often describe their problem as brain fog. While brainfog may occur in association with many health problems, most notablyfibromyalgia, it can also occur as a side effect of a conditioncalled allergic sinusitis.
Find Out More About Your Medicine
The leaflet that comes in the packet with your medicine will have detailed information about it, including how to take it and what side effects you might get.
If you no longer have the leaflet that came with your medicine, you can search for an online version of it using our medicines guide.
You may also find information on individual antihistamines on these websites:
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Are Antihistamines Good For Cold Symptoms
The common cold and allergic rhinitis share similar symptoms. So its only natural that many people reach for antihistamines when they have a cold. But are they effective? A statistical analysis of multiple studies found that antihistamines in general relieve cold symptoms in adults for the first 1 or 2 days only, with no benefit later on.
Tips For Staying Alert
In treating allergies or a cold with antihistamines, you may experience drowsiness, a common side effect of the medication.
How does this happen? Histamine is a chemical produced by the immune system to fight off allergens and germs. When there is a threat of allergies or infection , histamine is even more active. In its search-and-destroy process, it can cause allergy or cold symptoms such as runny nose, coughing, sneezing and itch eyes. Antihistamine medications relieve these symptoms by blocking the unwanted effects of histamine.
Unrelated to the immune system, histamine is also produced in the brain, where it plays an important part in feeling awake. Antihistamines used to treat respiratory symptoms can get into the brain and interrupt this work, making you feel drowsy.
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Why And How Allergies Can Make You Tired
The ragweed is in bloom or you visited a friend with a cat, and now your allergies are leaving you so exhausted youre dragging around all day. No, the gravitational force on Earth has not increased. It could be your allergies. But why and how can your allergies make you tired?
When you have an allergic reaction, your body releases proteins called proinflammatory cytokines, which are designed to neutralize invading particles, including allergens like pollen, pet dander, and mold. Researchers believe that cytokines act on the central nervous system, and prompt leukocytes and other cells to secrete IL-1 beta , a hormone-like substance that can make you feel lethargic and depress your mood. Perhaps fatigue from the inflammatory process is your bodys way of telling you to rest, so it can fight whatever evil nasty is plaguing your system.
Ironically, some allergy medications may also lead to poor sleep, and the same vicious cycle of insomnia and daytime drowsiness. Many antihistamines can leave you groggy, with a hung over feeling that may last through the day. Or, if you take them at night, you may sleep for a while, but then wake when the medication wears off. Think switching to a decongestant will help? In one study, 15 to 25% of decongestant users reported insomnia. But some doctors switch their patients to prescription nasal corticosteroids, which are not as likely to cause fatigue.
References:
Keep Your Bedroom Allergen
This is easier said than done, Dr. Hong says. If its seasonal allergies keeping you awake, take a shower before bed and leave dirty clothes outside your room. Keep your bedroom windows closed and run the air conditioning. If you use a window unit, make sure its recirculating the air and not venting it in from outside. For dust mite allergies, keep dust mite covers on your bedding. And if you suffer from pet allergies, make your bedroom an animal-free zone.
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How Much Will My Allergy Medication Cost
Once youve found an allergy medication that fits your needs, youll ultimately want a good price for it. All of the medications listed in this article have brand-name and generic forms. Most are also available over-the-counter. Their cost will largely depend on whether you buy them over the counter or with a prescription. And as it turns out, visiting your provider and getting a prescription for a generic version can be well worth it.
Lets take Claritin as an example. Claritin costs about $33 retail. If you get a prescription for the generic form, loratadine, you might pay about $10 cash instead for the same amount. Thats over 50% savings. Now, if you use a GoodRx coupon with your prescription, that same amount of loratadine can cost as little as $4, saving you 87% off the brand-name, over-the-counter price.
How To Take Antihistamines
Take your medicine as advised by the pharmacist or doctor, or as described in the leaflet that comes with it.
Before taking an antihistamine, you should know:
- how to take it including whether it needs to be taken with water or food, or how to use it correctly
- how much to take this can vary depending on things such as your age and weight
- when to take it including how many times a day you can take it and when to take it
- how long to take it for some types can be used for a long time, but some are only recommended for a few days
- what to do if you miss a dose or take too much
The advice varies depending on the exact medicine you’re taking. If you’re not sure how to take your medicine, ask a pharmacist.
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Shore Up Immune System With Allergy Shots
Known as allergy immunotherapy, allergy shots contain serums of multiple allergens to allow the body to become used to exposure to harmful substances such as dust or pollen. The shots can reduce allergy symptoms without taking medication that makes you drowsy. Be patient, however: Its not a quick fix, but over time and with regular injections a lot of people will feel better and be able to reduce the medications they need to use, says Stukus.
How Does Equate Allery Relief Work
The active ingredient in this medication is diphenhydramine HCl. This is a chemical that blocks histamines from permeating through your system. This makes Equate into an antihistamine, part of a group of medications sold over the counter and through prescriptions to combat allergy symptoms.
Equate is used to fight off several symptoms. If you are experiencing a runny nose, sneezing, or a scratchy cough, Equate will help to alleviate these symptoms. The medicine can also be used for allergy attacks, including breakouts of hives, development of rashes, and new reactions to previously unknown allergens. In some cases, Equate can be used to treat mild cases of Parkinsons disease.
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Allergy Remedies That Wont Make You Drowsy
Allergies are the sixth-leading cause of chronic illness in the United States, and more than 50 million Americans struggle with allergy symptoms each year, according to the Centers for Disease Control and Prevention. With allergy season arriving, theres no need to suffer with either the drowsiness of over-the-counter medications or the allergy symptoms that bother your eyes, lungs, nose, throat, sinuses, ears, skin, or stomach.
Poorly controlled allergies affect the eyes and nose, sleep quality, energy levels, work performance, and can really decrease quality of life if youre miserable all the time, says Dr. David Stukus, an allergist at Nationwide Childrens Hospital, in Columbus, Ohio, and a member of the board of directors for the Asthma and Allergy Foundation of America. A lot of people think thats the way to live, and they cant do any better.
Thats not the case, though. You just need to avoid antihistamines known to cause drowsiness, including chlorpheniramine, which can affect your reaction time and your ability to think quickly, says Stukus.
Here are 10 remedies for dealing with allergy symptoms without feeling sedated.
For access to exclusive gear videos, celebrity interviews, and more,
What You Can Do
If your medicine makes you feel worn out, donât stop taking it. You can try other ways to fight the side effect and get an energy boost:
- Get some exercise, like a quick walk or some stretches.
- Take deep breaths.
- Drink a little bit of caffeine, like coffee or tea.
If youâre taking an over-the-counter medication, ask your doctor or pharmacist if there are ânon-drowsyâ versions of it you can use instead. Itâs important to ask to make sure it wonât affect any other medications youâre taking.
Your doctor can help you handle any fatigue you feel from prescription medications. They might:
- Change your medication
- Change your dose
- Tell you to take your medicine at a different time, like in the evening or before bed
- Prescribe a medication to help you feel alert and awake
Donât take any medications that are supposed to help you stay awake, unless your doctor says itâs OK.
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How Antihistamines Treat Allergies
When your body comes into contact with whatever your allergy trigger is — pollen, ragweed, pet dander, or dust mites, for example — it makes chemicals called histamines. They cause the tissue in your nose to swell , your nose and eyes to run, and your eyes, nose, and sometimes mouth to itch. Sometimes you may also get an itchy rash on your skin, called hives.
Antihistamines reduce or block histamines, so they stop allergy symptoms.
These medicines work well to relieve symptoms of different types of allergies, including seasonal , indoor, and food allergies. But they can’t relieve every symptom.
To treat nasal congestion, your doctor may recommend a . Some medicines combine an antihistamine and .
Heres Something You May Not Know: Dph Is The Sole Active Ingredient In Both Benadryl And Zzzquil But Only One Is Indicated For Helping You Fall Asleep
Although Benadryl lists marked drowsiness as a potential side effect, it is not indicated for sleep on its packaging. In fact, Johnson & Johnson, the makers of Benadryl, declined to comment on this subject as it discusses an off-label use.
ZzzQuil products, on the other hand, have the exact same active ingredient. Therefore, these ZzzQuil products essentially work in the same way as Benadryl, but theyre marketed specifically to help you get sleepin the short-term, that is. ZzzQuil is indicated for the relief of occasional sleeplessness, and the warning label advises consumers to stop use and consult a doctor if theyre still having trouble sleeping after two weeks. When reached for comment, Procter & Gamble, the makers of ZzzQuil, emphasized these instructions. Benadryl doesnt contain any such warning, even though experts agree that its not good to take it over the long term.
But taking ZzzQuil to help you sleep could, theoretically, come with the same potential side effects of taking Benadryl, like next-day sleepiness. On the ZzzQuil site, the manufacturers note that there are many factors that could influence how well rested you feel the next morning, including the time you take ZzzQuil. They recommend you only take ZzzQuil if you know youll have enough time to get a full nights rest, however much that usually is for you.
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Consider Keeping Pets Out Of The Bedroom
Having pets on the bed can be an issue even if this isnt your primary allergy, since pets can have dust, pollen or other allergens clinging to their fur when they enter the room. Those with a pet dander allergy should strongly consider keeping pets off of the bed or out of the bedroom to make sleeping easier without allergy symptoms.
Should I Use Equate Allergy Relief
Choosing Equate Allergy Relief depends on what you want to get out of your treatment. If you need an immediate combination of a sleep aid and allergy medicine, Equate is a cheap brand that might provide you with some temporary relief. It works quickly to knock you out and calm most of the symptoms that would keep you up during the night.
Unfortunately, Allergy Relief suffers from the same drawbacks as Benadryl or any other allergy medication on the market. While it might temporarily relieve the symptoms of allergies, it will not do anything to cure the underlying allergy itself.
Its difficult to give a recommendation for a medicine that is so chock-full of side effects, too. Allergy Relief might give you a temporary stop to watery eyes, but do you really want a headache to replace it?
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Why Do Some Antihistamines Make You Sleepy
Sedation is a prominent side effect of older antihistamines, what we call first-generation antihistamines. Examples include:
The first-generation antihistamines can make you drowsy because they cross the blood-brain barrier, an intricate system of cells that regulates what substances pass into the brain. In fact, these older antihistamines are often marketed as sleep aids. The first-generation antihistamines are also used in cold-and-flu formulations to provide a side benefit of drowsiness when youre feeling ill and need plenty of rest.
Drowsiness is something to be aware of with first-generation antihistamines. They may increase the risk of falls or fracture in people 65 years or older. According to the Canadian Society of Allergy and Clinical Immunology, first-generation antihistamines are also linked to impaired driving as well as fatal car and flying accidents. These drugs can also cause dry mouth, constipation, and difficulty urinating.
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