When Allergy or Cold Medication Makes You Drowsy

Tips for Staying Alert

By Purvi Parikh, MD

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 (such as the common cold), 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.

What can you do about drowsiness from allergy medicines?

Some antihistamines are less likely to cause drowsiness than others. Reactions vary considerably from one person to another. What relieves your symptoms without making you sleepy may be different from what works for someone else.

When you find one that works for you, stick with it – check chemical ingredients and dosages before changing brands or generics. On the other hand, if one doesn’t work for you, try another type.

Does diphenhydramine (Benadryl®) make you sleepy? First-generation antihistamines such as diphenhydramine (Benadryl®) usually cause drowsiness because they are less likely to affect the histamine produced in the brain or have other unwanted effects in the brain. Currently, there is no non-drowsy Benadryl® on the market.

Non-drowsy allergy medicines do exist. Newer, second-generation antihistamines such as cetirizine (Zyrtec®), fexofenadine (Allegra®) and loratadine (Claritin®) – marketed as “nonsedating” – usually cause less drowsiness. An added benefit is that second-generation antihistamines last longer than Benadryl. Allegra is generally the least sedating.

Nasal spray antihistamines are also somewhat less likely to make you sleepy, since they target nasal passages directly rather than sending medicine throughout your body in the bloodstream. These are available only by prescription.

Regular use of an intranasal corticosteroid is not only safe but also an effective way to reduce use of antihistamines. They take a few days to start working, so you need to be patient. Ask your doctor or pharmacist about using an antihistamine with an intranasal corticosteroid the first few days. Some intranasal corticosteroids are available over-the-counter, while others are available as prescription medication.

To avoid daytime drowsiness, take an antihistamine in the evening rather than in the morning. It may help you sleep, with drowsy effects wearing off by the next morning. Be aware that drowsiness can last longer than you might expect – and that some antihistamines can cause vivid dreams.

Don’t drink alcohol when taking antihistamines, as it will increase the sedation.

What about antihistamines in cold and flu medications?

What many people may not know is that cold and flu medicines marketed to treat runny nose and sneezing usually include first-generation antihistamines – the more sedating types. That’s because they are often better at treating cold symptoms and drying up runny nose than the newer types.

Because of their sedating effect, cold medicines with antihistamines are labeled for nighttime use. Take this labeling seriously, as some include medications like doxylamine that are more sedating than others. Check labels for dosages as well, as these may vary, even within brands.

More is not better – read labels carefully and take only as recommended. Don’t supplement a multi-symptom cold medication with another single-ingredient antihistamine.

Be smart, be aware of allergy medication side effects

Smart use of allergy medications – knowing how they treat symptoms of an allergic reaction, being aware of potential unwanted side effects and, most important, monitoring their effect on you and your health – is just one step toward controlling allergy and cold symptoms. Even more important: knowing what you are allergic to and taking steps to prevent or reduce exposure.

If your allergy symptoms tend to last longer than two weeks or are not adequately controlled with over-the-counter medications, schedule an appointment with a board-certified allergist for a full diagnosis.

Antihistamines and intranasal corticosteroids are intended for symptom relief. If antihistamines or intranasal corticosteroids are causing side effects such as drowsiness or other problems, there are other treatment options your doctor can offer for relief from allergic reactions. These options include allergen immunotherapy and non-drowsy allergy medicines like second-generation antihistamines or nasal sprays.

Reviewed by:
Dennis Williams, PharmD, is an Associate Professor at the University of North Carolina Eshelman School of Pharmacy. He practices at UNC Medical Center with the pulmonary medicine medical service. He has served as a member of the National Asthma Education Program Coordinating Committee and the National Asthma Educator Certification Board. He serves on Allergy & Asthma Network’s Board of Directors.

24 Hour Tablets | Allegra® Allergy Relief Medicine

NON-DROWSY ALLERGY RELIEF

Read Reviews

Get all-day relief from tough allergy symptoms with Allegra^® 24 Hour Tablets. 

Relieve your hay fever and allergy symptoms like runny nose, sneezing, itchy, watery eyes, itchy nose, or itchy throat. Allegra^® starts working in one hour — twice as fast as Claritin* — and won’t leave you feeling drowsy like Zyrtec.^† That is why it’s the #1 allergist recommended non-drowsy allergy brand.^‡

  Fast-acting^§

  Non-drowsy

  24-hour relief

  Relieves indoor and outdoor allergies

If you’re not completely satisfied, get your money back guaranteed**

Allergies can really ruin your day.

Itchy throat.Sneezing.Watery eyes.

They can really get to you.

Unless you get to them fast, with Allegra Allergy.

Take Allegra at the first sign of symptoms – it starts working in one hour.

Allegra Allergy is non-drowsy and one tablet can keep the symptoms away for 24 hours,

relieving symptoms like itchy, watery eyes,

sneezing, runny nose, itchy nose or throat.

So you can live your greatness.

Get a $4 Coupon

Sizes: 

5-count tablets | 15-count tablets | 30-count tablets | 45-count tablets | 60-count tablets | 70-count tablets | 90-count tablets | 110-count club pack

*Starts working in one hour. Applies to first dose only.
^†Based on labeled warnings and clinical trials.
^‡Among branded OTC oral antihistamines.
^§Starts working in one hour.
^**Terms and conditions apply

WHERE TO BUY

Additional Sellers

Product Information

• Adults and children 12 years of age and over:
• Take one 180 mg tablet with water once a day; do not take more than 1 tablet in 24 hours.
• Children under 12 years of age: do not use.
• Adults 65 years of age and older: ask a doctor.
• Consumers with kidney disease: ask a doctor.

 

Do not use if you have ever had an allergic reaction to this product or any of its ingredients.

Ask a doctor before use if you have kidney disease. Your doctor should determine if you need a different dose.

When using this product:

• do not take more than directed
• do not take at the same time as aluminum or magnesium antacids
• do not take with fruit juices (see Directions)

Stop use and ask a doctor if an allergic reaction to this product occurs. Seek medical help right away.

If pregnant or breastfeeding, ask a health professional before use.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center right away.

For 30 count or larger count sizes:

• Safety sealed: do not use if carton is opened or if printed foil inner seal on bottle is torn or missing.
• Store between 20° and 25°C (68° and 77°F).
• Protect from excessive moisture.
   

For 15 count or smaller count sizes:

• Safety sealed: do not use if carton is opened or if individual blister units are torn or opened.
• Store between 20° and 25°C (68° and 77°F).
• Protect from excessive moisture.
• Use as directed.

Ingredients

Active Ingredients

Fexofenadine HCl 180 mg (in each tablet)

An antihistamine that works to relieve allergy symptoms of sneezing, runny nose, itchy/watery eyes, and itchy nose or throat due to hay fever or other upper respiratory allergies.

Purpose: Antihistamine

Inactive ingredients

Colloidal silicon dioxide, croscarmellose sodium, hypromellose, iron oxide blends, magnesium stearate, microcrystalline cellulose, polyethylene glycol, povidone, pregelatinized starch, titanium dioxide

See full ingredients list and functions

Get Effective, Long-Lasting* Allergy Relief Guaranteed

Don’t let allergies get in your way. Try effective, long-lasting* relief from the #1 allergist recommended non-drowsy brand.^† If you’re not completely satisfied, get your money back, guaranteed. 

See Terms & Conditions

See Guarantee

*One dose of Children’s Allegra lasts a full 12 hours.
^†Among branded OTC oral antihistamines. Use As Directed.

Excludes Allegra Hives.

Frequently Asked Questions

• You may be able to use your HSA or FSA tax-preferred savings account to purchase certain OTC products, including Allegra^®. The passage of the CARES Act by Congress includes provisions to restore OTC eligibility under tax-preferred HSA and FSA accounts. Plan details vary, so save your receipt and check with your benefits or health provider for eligibility.

• No. Use Allegra® only as directed.

• If you experience allergy symptoms while pregnant or breastfeeding, consult with your healthcare professional.

• Yes. Allegra® 24 Hour Tablets are lactose free.

• Allegra^® 24 Hour Tablets are not certified gluten free, but none of the ingredients are derived from wheat, barley, spelt, oats, or rye.

• Allegra^® 24 Hour Tablets are vegetarian. They do not come not from any animal origin. They do not contain casein, eggs, dairy, lactose, iodine, peanuts, shellfish, soy, tree nuts, or whey.

• Allegra^® should be used as directed according to the product label. Maximum effectiveness has been demonstrated when taken with water. Taking Allegra^® with fruit juice is not a safety risk, but the effectiveness of the medicine may be reduced.

• Do not cut or break Allegra^® products in half. Use only as directed.

• No. Allegra^® is approved for human use only. Please refer to the product label and use as directed.

Contact us

Have questions or comments?

Call toll-free 1-800-633-1610 or Contact Us Online.

Get tips for managing indoor and outdoor allergies

Seasonal Allergies

Allergy season is different for everyone. That’s because different kinds of outdoor allergens — or irritants — get distributed into the air year-round.

Read Article

Adult Outdoor Allergies

Outdoor allergy sufferers: You’re not alone! Millions of Americans experience some kind of outdoor allergy.

Read Article

Adult Indoor Allergies

There’s no place like home … for allergies! Just stepping indoors — at home, work, or school — exposes you to numerous allergens.

Read Article

Also available as gelcaps

Allegra

^® Allergy 12 Hour Tablets

Get relief from tough allergy symptoms every day with Allegra^® 12 Hour Tablets for adults and children 12 years of age and over.

More info

Allegra

^® Allergy 24 Hour Gelcaps

Get all-day relief from tough allergy symptoms with Allegra^® 24 Hour Gelcaps for adults and children 12 years of age and over.

More info

What and how to treat allergies?

With various allergic symptoms – runny nose, conjunctivitis, urticaria, etc. – we, of course, resort to the help of antihistamines. But at the same time, we rarely think about their features: for example, to which generation this or that remedy belongs, what side effects it has. And it should.

Determining the diagnosis

Let’s start with what is currently known two generations of antihistamines . The first antihistamines began to be used in the 40-50s of the last century. These drugs initially had a number of serious side effects, which, however, did not prevent them from “gaining popularity” – the work on their creation was even awarded the Nobel Prize! ²
Meanwhile, medicine was advancing. In the 1980s, 2nd generation antihistamines appeared. They acted faster, more efficiently and were deprived of a number of side effects. But, nevertheless, many representatives of first-generation antihistamines continue to be widely used, and this despite the fact that reports of undesirable consequences of their use appeared almost 60 years ago! ¹
To this day, we continue to treat allergies with outdated remedies. Out of ignorance or “out of habit” – it doesn’t matter! Agree, if there are more modern and safe drugs, it is unreasonable to use their less successful predecessors, which can harm the health of you and your children.
Still in doubt? Let’s talk in more detail about the dangers of first-generation antihistamines, what advantages second-generation drugs have over them, and which of their representatives should be remembered.

Diagnosis established

“Search and neutralize” ²
Imagine: an allergen enters the body, an allergic reaction begins, during which histamine is released. By binding to receptors, this substance causes swelling, redness of the skin, bronchospasm, difficulty in nasal breathing, so it is very important to block its action, stop the inflammatory reaction.
Histamine receptors are found in blood vessels, smooth muscles, the heart, tissues of the central nervous system, epithelium, and also in the brain. ⁷ In order to relieve allergy symptoms, it is enough to act on peripheral receptors. However, first-generation antihistamines also block receptors in the brain, resulting in a number of side effects:
– They act on the central nervous system, and therefore cause sedation – drowsiness, inhibition of reactions .
– Their action is not stable and durable, which makes it necessary to use high doses several times a day (up to 4-6 times) of these drugs. ( And this despite the fact that the therapeutic concentration is reached only after 2 hours! ³ ) As a result, when using these drugs, there is a possibility of a whole range of side effects: drowsiness, dizziness, lethargy, impaired coordination, inability to concentrate.
– They do not have selectivity (“targeting” action on histamine receptors), they also block other types of receptors, which can cause tachycardia, dryness of the nasopharynx and oral cavity, urinary retention, constipation, and visual impairment. The condition of bronchial asthma may even be aggravated (sputum viscosity increases) and cardiac arrhythmia may occur as a result of toxic effects on the heart. ¹
– May be addictive, and with prolonged (more than 7-10 days) use, the therapeutic activity of the drug decreases.
It is clear that in diseases such as bronchial asthma, chronic urticaria and perennial allergic rhinitis, requiring long-term use of antihistamines, the use of first-generation drugs is highly undesirable. ²
Mistakes we make ¹
Perhaps the biggest mistake of using 1st generation drugs is that many mothers give these drugs to babies before bed at night, hoping that the sedative effect will contribute to a deeper sleep of the child.
In the course of recent studies of the effect of 1st generation antihistamines on the functioning of the brain, it was proved that they cause unnatural sleep, disrupt the course of sleep phases! ¹ The onset of REM sleep (necessary for memory formation and brain development) is delayed, its duration is reduced. The use of first-generation antihistamines often leads to daytime sleepiness, reduced daytime activity, and impaired brain function, which is especially dangerous when they are used in children.

It has also been proven that 1st generation drugs contribute to a significant decrease in the ability of schoolchildren to learn, impaired concentration and memory.
With the regular use of such funds, cognitive functions (the ability of the brain to perceive and process information) are seriously affected, and therefore there is a threat to the full intellectual development of the child.

A special study was conducted in the UK with 1,834 teenage students taking exams. Among the students were those who suffered from allergic rhinitis. They were divided into two groups – those who were not treated with anything, and those who took first-generation antihistamines. For the former, the probability of “failing” the exam was 40%, for the latter – 70%. ¹
In general, it becomes clear why many developed countries are raising the issue of limiting the use of first-generation antihistamines without a prescription. ²
So, if you see one of the following substances on the package or in the instructions, know that you have a 1st generation antihistamine in your hands: Diphenhydramine, chloropyramine, promethazine, dimethindene, clemastine, mebhydrolin, etc. . ²

New generation chooses… ^2.3
What kind of allergy medications do we, modern people, need? Well, of course, those that:
– act quickly and efficiently;
– in therapeutic doses, they practically do not have a sedative effect;
– work even at a high concentration of histamine in the blood, without harming the body;
– suitable for the treatment of most allergic diseases, including chronic forms;
– practically do not affect the ability of children to learn and concentrate;
– contribute to improving the quality of life against the background of the current allergic disease.
It is these qualities that second-generation antihistamines have. These drugs include cetirizine (Zodak®), levocetirizine (Zodak Express®), and fexofenadine (Allegra).
These drugs can also be taken by children. Zodak® in the form of drops can be used in children from 6 months. ⁴ A Zodak® and Zodak Express® tablets are approved for use from 6 years of age.