by The Curist Team and reviewed by Dr. Marc Goldstein, MD, Curist Medical Advisor

Curist delivers FDA-approved medicines to your door at half the price of traditional brands. We hope everyone stays safe and healthy during this time.

Curist customers ask questions all the time, and we've put together this handy guide for the most frequently asked antihistamine and allergy questions.

Can I Take Two (24-Hour) Antihistamines In a Day?

You should not double up on antihistamines or take two different types in one day, unless your doctor specifically directs you to do so.  Antihistamine dosage is based on rigorous testing, and exceeding the recommended daily amount can cause unintended side effects like hallucinations or seizures. If you find your antihistamine is not providing relief, it may be time to switch to another antihistamine or add a nasal spray into your allergy routine (like Curist Allergy Nasal Spray), rather than increase your dosage.

Can I Take Two Different Kinds of Antihistamines at Once?

Different antihistamines have the potential to interact with each other, increasing the chance of side effects and potentially leading to antihistamine overdose.  Do not combine two antihistamines, unless your doctor specifically directs you to do so. 

Do I Bother Taking an Antihistamine Again If It Stopped Working For Me in the Past? 

Factors like age, stress, new allergy triggers, and environmental changes can affect how antihistamines work in your body. An antihistamine also may not be as effective if you don’t take it consistently throughout an allergy season or episode.  Some people develop a subsensitivity to a particular antihistamine after a long period of usage, which reduces the efficacy of that particular product. Changing to a different antihistamine will often restore efficacy. Taking a break from an antihistamine and trying it again at a later time may also restore the previous (effective) response. With Curist, you can try medications risk-free for 30 days and return anything that may not work out for you for a full refund!

Should I Take Antihistamines During the Day or At Night? 

This depends on the antihistamine and whether your symptoms are worse during the day or night.  Levocetirizine (brand Xyzal and Curist brand here) should be taken at night, and it will provide relief while you sleep and through the next day. Cetirizine (brand Zyrtec) may cause drowsiness, so it may be better to take it before you sleep rather than during the day. Loratadine (brand Claritin) and fexofenadine (brand Allegra) are non-drowsy antihistamines that can be taken during the day.

Can I Safely Take Antihistamines Every Day?  If So, How Do I Make Sure I Don't Develop Antihistamine Tolerance?

Second- and third-generation antihistamines are safe to take every day or as needed for long-term allergy management, provided you do not exceed the recommended daily dosage. Sometimes, people experience less and less relief from their antihistamines over time. When this happens, the culprit may be  an antihistamine tolerance (read above), or a worsening or evolution of allergies and symptoms. Over time, allergies may become more severe or cause cross-reactivity with similar substances. Antihistamines that previously worked for certain triggers and symptoms may not work against your body’s newer reactions. If this occurs, it’s time to try a new antihistamine or bolster your routine with a nasal spray.

Can I Cut My Antihistamine Tablet in Half?

Many antihistamines can be cut in half without affecting their safety. Keep in mind, however, that a half-dose is 50% of what the FDA recommends you may need for the drug to work effectively. If an antihistamine is formulated with an extended-release component (like a decongestant) or is in a gel capsule, it should not be cut in half. The following table only applies to solid antihistamine tablets without added components:

Can I Drink Alcohol When Taking Antihistamines?

First-generation antihistamines that cause drowsiness, like Benadryl, should not be mixed with alcohol. An exception to this rule is if you are drinking alcohol and happen to have an allergic reaction. In that case, managing your reaction is more pressing than avoiding the adverse effects of combining a first-generation antihistamine with alcohol. It is not recommended to drink alcohol with second- or third-generation antihistamines, either. The sedative effects of alcohol are not as intense when combined with these newer antihistamines, but they still have the potential to cause unwanted side effects. The safest option for preventing allergies without having to sacrifice your alcohol consumption is Curist Nasal Spray, which does not require you to avoid alcohol.

Can I Give Antihistamines to My Child Without Talking To A Doctor?

If you suspect your child has allergies, it is important to consult with a pediatrician before administering over-the-counter (OTC) medications. Children with allergies often have other underlying conditions, such as asthma and eczema, which require prescriptions and long-term management. Please make sure to read the directions for each antihistamine carefully, as each medicine has different guidelines for the minimum age for use.

Do Antihistamines Make My Quality of Sleep Worse? 

First-generation antihistamines are notorious for causing drowsiness, but they don’t necessarily guarantee a good night’s sleep. These older antihistamines are linked to instances of unexpected hyperactivity in some people, which may cause sleepwalking and other sleeping disorders. Newer antihistamines are much more effective at providing relief without the sedating effects, leading to better night’s sleep without the itching, sniffing, and sneezing. To learn more, check out our blog about Allergies and Sleep by Curist Allergy Advisor Dr. Marc Goldstein. 

Can I Use Antihistamines As a Sleep Aid? 

Using antihistamines as a sleep aid is not recommended. While some antihistamines may help you fall asleep faster, your body eventually builds a tolerance against any sedative properties. Antihistamines should not be used as a solution for chronic insomnia or other sleep disorders. That said, if you are having difficulty sleeping because of your allergy symptoms, a daily antihistamine may help reduce those symptoms and help you sleep better.

What Happens If I Miss One Dose of Antihistamine?

If you miss a dose of your antihistamine, histamine release in your body will eventually resume and result in allergy symptoms. Take your missed dose as soon as possible, or wait for your next dose to maintain your established schedule. Do not exceed the daily limit or double your dose to compensate for a missed dose. 

Are there questions that you have that we haven’t answered yet? Feel free to send us an email at hi@curistrelief.com and we’d be happy to help!