Updated on August 13, 2023
9 min read

When is it Safe to Drink Alcohol After Taking Allegra?

Allegra and Alcohol

Allegra is a popular brand name for the anti-allergy medication fexofenadine. It belongs to a large class of anti-allergy medications known as antihistamines.1,2,3,4

Like other medications, Allegra and other antihistamines have side effects and interactions. Included in these interactions are the hazards associated with mixing Allegra and alcohol.


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Allergies and How Allegra Works

Allergic reactions can arise from various sources, such as: 

  • Food
  • Dust
  • Pollen
  • Mold
  • Pet dander
  • Insect bites

When allergens enter the body, your immune system recognizes them as potential threats and releases chemicals to combat them. One such chemical is histamine, which can trigger allergic symptoms to eliminate the allergens, like: 

  • Runny nose
  • Itchy eyes
  • Swelling
  • Hives 

Allegra and other antihistamines block histamine’s action by binding to histamine-1 (H1) receptors. These are the same receptors that histamine binds to to produce its effects.5,6,7

Depending on the condition and the person’s age, a healthcare provider can prescribe oral Allegra tablets in varying strengths:3,8 Some examples of dosing include the following: 

  • 30 mg for allergic rhinitis in children aged 6-12 years
  • 120 mg for allergic rhinitis in adults
  • 180 mg for chronic urticaria in adults and children aged 6-12 years

Can You Drink Alcohol with Allegra?

It’s generally safe to drink alcohol in moderation, but combining alcohol with certain medications can lead to potential risks and complications. That includes Allegra and other antihistamines, as alcohol can amplify certain side effects.8

What Are the Risks of Combining Allegra and Alcohol?

Both alcohol and Allegra can depress the central nervous system. When taken together, they can amplify each other’s sedative effects.

It can potentially cause the following:2,7,9,10,11,12

  • Extreme drowsiness
  • Reduced concentration
  • Inability to drive safely and perform other tasks requiring mental alertness
  • Impaired motor skills and coordination
  • Decreased reaction times
  • Unsteady movements
  • Increased risk of falls, fractures, injuries, or accidents 
  • Serious health consequences (like overdose, respiratory distress, coma, or even death)

If you’re medicating with Allegra:8,9

  • Ask your medical provider first if it’s okay for you to drink alcohol. They’ll consider your unique situation, including your medical conditions and other medications you take.  
  • You may be allowed to drink if you follow specific rules, like drinking in moderation or waiting a few hours after taking Allegra. 
  • You’re fully aware of the effects of combining Allegra and alcohol on you. 

How Long After Taking Allegra Can I Drink Alcohol?

There's no specific waiting period mentioned for Allegra concerning alcohol consumption. 

However, waiting for a few hours before drinking is good advice. This should allow the medication to be metabolized and eliminated from the body, reducing the risk of interactions.

For your guidance, Allegra’s effect starts to kick in after one hour, reaching maximum effect within two to three hours. However, some people can still feel the impact by up to 12 hours, which aligns with Allegra’s elimination half-life of 14.4 hours.13,14

Can I Drink Alcohol After Taking Allegra 180 mg?

Drinking alcohol can enhance Allegra’s side effects. This is more pronounced with Allegra 180 mg, Allegra’s most potent form. Taking alcohol and Allegra 180 mg can lead to a higher level of sedation.

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What Other Things to Avoid When Taking Allegra

Aside from alcohol, there are other substances you need to avoid when taking Allegra. You should be aware of these substances to ensure the effectiveness and safety of Allegra.

Fruit Juices

Certain fruit juices can interfere with Allegra’s absorption and decrease the drug’s level in the body.

These fruit juices include:

  • Apple
  • Grapefruit
  • Orange

Refrain from drinking large amounts of these juices or drink only water so that the body absorbs Allegra better.2,3,15,16 

Sedating Medications

Allegra can already cause drowsiness. Combining it with sedatives and CNS (central nervous system) depressants can lead to additive sedation.

Examples of these substances include:3,11,12,16

  • Cough and cold remedies containing another antihistamine (like olopatadine intranasal)
  • Tranquilizers
  • Sleeping pills
  • Neurotic pain medications
  • Muscle relaxers
  • Medicine for seizures
  • Antidepressants (like isocarboxazid and tranylcypromine)
  • Other sedatives and CNS depressants

Unless your doctor instructs you, you should avoid taking multiple antihistamines simultaneously or combining Allegra with other drowsy medications.


Avoid taking aluminum and magnesium antacids within two hours before or after taking Allegra. These medications can decrease the absorption of Allegra and reduce its effectiveness.3,12,17

Other Medications That Interact with Allegra

Some drugs can increase the concentration of Allegra in the body, enhancing the side effects. This means you should avoid co-administration.

Examples of such drugs are:16

  • Cancer drugs (like erdafitinib, leniolisib, and tepotinib)
  • Migraine medications (like lasmiditan and metoclopramide intranasal)
  • Trofinetide (a medication for Rett syndrome)

On the other hand, some drugs can decrease Allegra’s concentration. One known example is the lung cancer drug sotorasib. It would be best if you also avoided coadministration. But if use is unavoidable, your healthcare provider may help you with dosage modifications.16

This list of things to avoid with Allegra isn’t exhaustive. Always consult your healthcare provider or pharmacist for guidance on potential interactions and other things to avoid. They can provide personalized advice based on your medical history and medication regimen.

Can I Drink Alcohol While Taking Allergy Medicine?

Whether it’s safe to drink alcohol while taking an antihistamine relies on the specific type of antihistamine you use. 

If you take older, first-generation antihistamines, you should avoid alcohol altogether. This is because they’re more likely to cause drowsiness than second-generation antihistamines. 

Mixing alcohol with a second-generation antihistamine is less likely to result in complications. However, that doesn’t mean it’s okay to do so. Experts still recommend refraining from drinking when on medication.

First-Generation Antihistamines

First-generation H1 antihistamines can cross the blood-brain barrier and are more likely to make you sleepy and impair your cognitive and psychomotor functions. Their combination with alcohol can produce a higher level of sedation than second-generation antihistamines.5,7,18,19 

First-generation antihistamines include:11,12,18

  • Brompheniramine (Dimetapp, Bromfed)
  • Chlorpheniramine (Chlor-Trimeton, Aller-Chlor)
  • Dimethindene (Fenistil)
  • Triprolidine (Actifed, Histex)
  • Cyclizine (Bonine, Marezine)
  • Hydroxyzine (Vistaril, Atarax)
  • Meclizine (Bonine, Dramamine Less Drowsy)
  • Azatadine (Optimine)
  • Cyproheptadine (Periactin)
  • Ketotifen (Zaditor, Alaway)
  • Carbinoxamine (Palgic, Histex CT)
  • Clemastine (Tavist, Dayhist)
  • Dimenhydrinate (Dramamine)
  • Diphenhydramine (Benadryl)
  • Doxylamine (Tylenol Cold and Cough Nighttime, Vicks NyQuil, Unisom, Nighttime Sleep Aid)
  • Antazoline (Vasocon-A)
  • Promethazine (Phenergan)
  • Doxepin (Silenor)
  • Cinnarizine (Stugeron, Joy-Travel)

Second-Generation Antihistamines

Compared to their older counterparts, second-generation H1 antihistamines don’t penetrate the blood-brain barrier or do so in a lesser manner. 

Second-generation antihistamines are sometimes called “non-sedating” or “non-drowsy” antihistamines. However, they can still make you sleepy to a lesser extent. It’s still best to avoid drinking alcohol when taking a dose unless your healthcare provider permits it.5,7,12,18,19,20

Second-generation antihistamines include:7,18

  • Fexofenadine (Allegra)
  • Cetirizine (Zyrtec)
  • Levocetirizine (Xyzal)
  • Desloratadine (Clarinex)
  • Loratadine (Claritin)
  • Olopatadine (Pataday, Patanol)
  • Azelastine (Astelin, Astepro)
  • Emedastine (Emadine)
  • Epinastine (Elestat)
  • Ebastine 
  • Acrivastine (Semprex)

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What Allergy Medicine is Best with Alcohol?

There are no guidelines for determining the best allergy medications with alcohol. However, antihistamines with zero or fewer sedative effects are generally safer with alcohol. This makes second-generation antihistamines already ahead of their first-generation counterparts. 

However, not all second-generation antihistamines are automatically good picks. There are still variations between these drugs regarding how much they disrupt cognitive and psychomotor functions.5

Criteria for Allergy Medicine’s Sedative Potential

Researchers used sedative parameters — like proportional impairment ratio (PIR) and brain H1 receptor occupancy (H1RO) — as an indirect gauge. 

Coincidentally, the Consensus Group on New Generation Antihistamines (CONGA) has set criteria for defining a “non-sedating” antihistamines:5,6,20

  1. There should be no “incidence of subjective sleepiness.”
  2. There should be no impairment of “objective and psychomotor functions.” Several studies used PIR as a measure of this criterion. The higher the PIR, the higher the drug’s impairment tendency.
  3. There shouldn’t be a significant amount of H1RO. It’s a helpful index for measuring a drug’s blood-brain permeability and sedative potential, categorizing antihistamines as follows:
  • Less than 20% H1RO: non-sedating
  • 20% to 50% H1RO: moderate or less sedating
  • More than 50% H1RO: sedating

Fexofenadine (Allegra)

A statistical analysis of several studies supports fexofenadine (Allegra) as the least drowsy among second-generation antihistamines.7,21 Such a claim makes an excellent argument to declare Allegra as the best allergy medication with alcohol.

One study reported -0.1% H1RO for 120 mg fexofenadine, classifying the drug as “non-sedating.” This finding supports that fexofenadine doesn’t cross the blood-brain barrier very much, if not at all.6,11,22 

In the same study, fexofenadine didn’t show significant differences from the placebo regarding subjective sleepiness and objective psychomotor tests.6,11 

In another study comparing the PIR of several antihistamines, fexofenadine scored the lowest score of 0.00. This means it has the least potential to cause impairments.5,6

Lastly, in a review of multiple studies involving multiple dosages, fexofenadine is the only drug that showed no sedation, even at higher doses. (Note that these are controlled studies.) The other second-generation antihistamines—cetirizine, loratadine, and desloratadine—showed no sedation at lower doses but had low to moderate sedation at higher doses.7,23


Like fexofenadine, ebastine has less than 20% H1RO at 10 mg and is classified as “non-sedating.”11 This finding makes a good case for ebastine as a safe antihistamine with alcohol.

However, the limited range of doses where ebastine was studied hinders it from being proclaimed as good as fexofenadine. The range only went up to three times of a single ebastine dose; with fexofenadine, it’s six times.5

Cetirizine (Zyrtec)

Cetirizine (Zyrtec) is potentially safe but only at low doses. It has less than 20% H1RO at 10 mg and is classified as “non-sedating” at this dose.11 One thing that works against cetirizine is its dose-dependent sedation and impairment.

In the study where 120 mg fexofenadine showed -0.1% H1RO, 20 mg cetirizine showed a 26.0% H1RO. At this point, cetirizine is now “less sedating.”6

Moreover, cetirizine have low sedation at recommended doses but moderate sedation at higher doses.2,5,23

Remaining Second-Generation Antihistamines

Like cetirizine, loratadine (Claritin) showed dose-ranging impairment. It showed no sedation at recommended doses but had low sedation at higher doses.5,7,23

For desloratadine (Clarinex) and levocetirizine (Xyzal), the lack of dose-ranging studies excludes them from being classified as “non-sedating.”5

Olopatadine, azelastine, mequitazine, and epinastine have shown H1RO numbers enough to be classified as either “non-sedating” or “less sedating.” However, we need more studies to support or debunk their positions.1


Combining alcohol and Allegra (fexofenadine) can present potential risks and complications. The interaction between Allegra and alcohol may cause increased drowsiness, impaired coordination, and other adverse effects. If you choose to drink, consider doing so in moderation or wait a few hours after taking medication.

Drinking alcohol while taking Allegra isn’t the only precaution you should consider. Grapefruit juice, sedating medications, antacids, and other medications can interact with Allegra differently.

The risks can vary when you consume alcohol with other allergy medicines. Second-generation antihistamines are generally safer due to their lesser sedative effects. 

Interestingly, based on studies, Allegra emerged as the safest antihistamine to take with alcohol. However, that doesn’t mean alcohol intake is automatically acceptable when on medication. 

Ultimately, prioritizing your health and well-being is crucial over alcohol consumption. The general guideline is to avoid drinking alcohol while taking medications. We recommend you always seek guidance from a healthcare professional before taking fexofenadine with alcoholic beverages.

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Updated on August 13, 2023
23 sources cited
Updated on August 13, 2023
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  17. fexofenadine (OTC) - Warnings.” Medscape. 
  18. Simons FE., Simons KJ. “H1 antihistamines: current status and future directions.” World Allergy Organ J, 2008.
  19. Weiler et al. “Effects of Fexofenadine, Diphenhydramine, and Alcohol on Driving Performance: A Randomized, Placebo-Controlled Trial in the Iowa Driving Simulator.” Annals of Internal Medicine, 2000.
  20. Holgate et al. “Consensus group on new-generation antihistamines (CONGA): present status and recommendations.” Clinical & Experimental Allergy, 2003.
  21. Mann et al. “Sedation with “non-sedating” antihistamines: four prescription-event monitoring studies in general practiceCommentary: Reporting of adverse events is worth the effort.” BMJ, 2000.
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