Drug Interactions, Kratom Guides

Fexofenadine and Kratom: Here’s All You Need To Know

Fexofenadine and kratom are two very distinct compounds: one is an antihistamine while the other is a psychoactive herbal compound.

These two compounds interact in some ways but not in others. 

It’s useful to know the usual ways different compounds can interact so you can make a more informed decision, though nothing beats the advice from your doctor.

Last updated 5 months ago by Wade Paul

Fexofenadine and Kratom: Here’s All You Need To Know

Does Kratom Interact With Fexofenadine (Allegra)?

Yes, fexofenadine and kratom might interact with each other. This isn’t necessarily a dangerous interaction, but you need to be aware of it, and it’s always best to speak to your doctor before combining them. 

Kratom and antihistamines interact primarily in the way they’re metabolized. They compete with each other, potentially leading to elevated levels in the bloodstream. 

However, fexofenadine is minimally metabolized; only around 5% of it undergoes metabolization in the liver. Most of the compound is eliminated unchanged via the feces and urine [1].

The likelihood of any adverse interaction seems low but still talk to your doctor. 

Is it Safe to Take Kratom With Fexofenadine?

Yes, it should be safe to take kratom with fexofenadine, but speak with your doctor first.

Very little in the scientific literature suggests a dangerous interaction between fexofenadine and kratom. If both compounds are taken with proper dosage, and there’s no misuse, the risk stemming from an interaction should be negligible.

This, of course, does not mean there’s no risk. Mixing kratom and medications will always carry the potential for severe adverse effects. Kratom has been minimally studied, so there’s still much we don’t know. Always talk to your doctor before using it with other medications. 

What is Fexofenadine (Allegra)?

Fexofenadine — sold commercially as Allegra — is an antihistamine medication. 

Histamines are organic compounds involved in local immune responses and a vast suite of other physiological responses. 

Antihistamines work by blocking the activity of histamine receptors in the body. 

There are several types of histamine receptors, and antihistamines are classified according to which ones they inhibit. Fexofenadine is an H1-receptor antagonist.

H1 antihistamines are further classified as ‘first’ or ‘second’ generation. 

Fexofenadine is a second-generation antihistamine and is not likely to cross the blood-brain barrier [2]. Because of this, it doesn’t cause much sedation like the older generation antihistamines. 

Fexofenadine Specs:

Drug Name Fexofenadine
Trade Name Allegra
Classification Antihistamine
CYP MetabolismFexofenadine is not meaningfully metabolized
Interaction With Kratom Unknown
Risk of InteractionLow to moderate

What is Fexofenadine Used for?

According to the FDA, fexofenadine is approved for the following uses:

  • Seasonal Allergic Rhinitis
  • Chronic Idiopathic Urticaria (hives)

Fexofenadine offers relief for the symptoms of chronic idiopathic urticaria like rashes and skin bumps. 

It also provides relief from the symptoms associated with allergic rhinitis, such as sneezing, rhinorrhea, itchy nose/palate/throat, watery eyes, etc. 

However, it is important to note that fexofenadine treats only the symptoms and does not cure the underlying conditions.

The scientific literature suggests that fexofenadine is just as effective as loratadine or cetirizine in the treatment of allergic rhinitis [3]. Additionally, a 2018 review found it to be safe for the use of individuals with inherited long QT syndrome [4].

What’s the Dose of Fexofenadine?

The usual dose is 60 mg of fexofenadine twice daily or a single 180 mg dose.

Patients with hepatic impairments should not exceed 60 mg in one day.

Lastly, children 6 to 11 should take fexofenadine in 30 mg doses twice daily.

These recommendations stay the same whether the treatment is for seasonal allergic rhinitis or chronic idiopathic urticaria.

Generic & Brand Name Versions

Fexofenadine is available under the following brand names:

  • Allegra
  • Allegra Allergy 12 hour
  • Allegra Allergy 24 hour
  • Children’s Allegra
  • Mucinex Allergy

What Are the Side Effects of Fexofenadine

The use of fexofenadine in controlled studies has led to the appearance of the following adverse effects [5]: 

  • Headache
  • Nose bleeds
  • Upper respiratory complaints, including infection, sore throat, cough, and sinusitis
  • Rash
  • Asthma
  • Infection
  • GI symptoms, including abdominal pain, nausea, and diarrhea
  • Leukopenia
  • Back pain
  • Weakness
  • Sedation/drowsiness
  • Dry mouth

The most common of these are drowsiness, fatigue, and dry mouth.

There’s no real contraindication to fexofenadine unless you’re sensitive to one of its compounds. There’s minimal hepatic involvement in metabolization, so it is safe to use for people with liver pathologies. 

What is Kratom?

Kratom is derived from Mitragynine speciosa leaves.

Kratom is only minimally processed: the leaves of the kratom plant are harvested and ground down into a powder.

Kratom has many benefits due to the powerful plant-based alkaloids inside it. These are natural compounds that often have pharmacological properties. 

Scientists have identified mitragynine and 7-hydroxymitragynine as the two main alkaloids in kratom. 

What is Kratom Used for?

There are many ways people use this kratom. We’re just now learning about its uses, but people in Southeast Asia, where it grows naturally, have been using it medicinally for centuries. Kratom isn’t some holistic medicine based on folklore either — science backs up these traditional uses.

So, what can kratom do? 

Here’s a look at some of its many benefits. 

What’s the Dose of Kratom?

The effects kratom produces are dependent on the dosage.

This is the main fact to remember about kratom’s properties: if you don’t control the dosage, you won’t be in control of the effects.

Follow this basic dosing guide to achieve the desired effects. Just remember these are averages.

  • Low dose (1 – 5 g): Acts as a stimulant and nootropic.  
  • Medium dose (5 – 10 g): Produces more potent analgesic and anxiolytic effects that crowd out the stimulating properties.
  • High dose (10 – 15 g): Strong pain and anxiety with sedation. 

What Are the Side Effects of Kratom?

Kratom consumption can cause a number of side effects, though they’re usually not serious. 

The most common side effects include:

  • Constipation
  • Dizziness
  • Insomnia
  • Nausea
  • Itchiness
  • Loss of muscle coordination

More serious adverse effects include:

  • Low blood pressure
  • Low libido
  • Nausea
  • Poor appetite
  • Seizures
  • Tremors

The most significant adverse effect of kratom has to be the possibility of developing an addiction. Even then, kratom addiction is vastly different than an addiction to opioids. It’s not as strong, and the withdrawal symptoms are easier to manage and overcome. Plus, kratom is generally safe and unlikely to cause overdose or death.

These occurrences are extremely rare and almost always involve other drugs. Kratom is less harmful in this sense than pharmacological drugs. Make sure you use kratom responsibly, and you’ll avoid these issues.

Suggested Reading: How Long Should I Wait Between Doses?

What Are the Different Types of Kratom?

As we mentioned, the dose will highly influence the effects you feel, but there’s another thing you need to consider — strains. 

While it can get overwhelming, this is excellent news because these strain types allow you to personalize your kratom experience even further.

Even though all strains have the same basic effects, each one excels at producing certain benefits more than others.

Here’s a look at how strains are categorized and the tendencies of each group.

A) White Vein Kratom

White vein kratom is most associated in the kratom community with the nootropic and stimulant benefit of the plant.

If you are mainly interested in kratom as a mental supplement or as a way to improve your mood, white vein kratom will give you the biggest bang for your buck.

B) Red Vein Kratom

Red vein kratom works best if you want to take advantage of its pharmacological aspects.

Those with chronic pain or other conditions usually gravitate towards this strain because of the relief they provide. 

However, it is also adept at producing generalized sedative effects and feelings of relaxation. Many use it as a sleeping supplement. 

C) Green Vein Kratom

Green vein kratom is slightly different from red and white. Instead of providing a targeted experience, green strains give the whole range of kratom’s benefits without overly emphasizing one aspect. 

This isn’t effective if you really need energy or pain relief, but it’s a great choice for those that want a little bit of everything. 

D) Yellow Vein Kratom

Yellow vein strains are similar to green, except less potent. In fact, it’s the weakest out of all the strains in terms of potency: perfect for first-timers! 

One theory is that yellow strains are a mix of white and red. Many people prefer these strains and don’t find them weak or ineffective.

Key Takeaways: Is it Safe to Mix Kratom & Fexofenadine (Allegra)?

Very likely, it’s safe to mix kratom and fexofenadine. Both can cause sedation, which can be dangerous; however, the likelihood of fexofenadine causing marked sedation is low. 

Still, there are too many unknowns when it comes to kratom. It’s always best to talk to your doctor before using it with other medications.

Remember to be on the lookout for any signs of kratom addiction and follow the recommended safety protocols of both compounds.


  1. Smith, S. M., & Gums, J. G. (2009). Fexofenadine: biochemical, pharmacokinetic and pharmacodynamic properties and its unique role in allergic disorders. Expert opinion on drug metabolism & toxicology, 5(7), 813-822.
  2. Compalati, E., Baena-Cagnani, R., Penagos, M., Badellino, H., Braido, F., Gómez, R. M., … & Baena-Cagnani, C. E. (2011). Systematic review on the efficacy of fexofenadine in seasonal allergic rhinitis: a meta-analysis of randomized, double-blind, placebo-controlled clinical trials. International archives of allergy and immunology, 156(1), 1-15.
  3. Simpson, K., & Jarvis, B. (2000). Fexofenadine. Drugs, 59(2), 301-321.
  4. Welzel, T., Ziesenitz, V. C., Seitz, S., Donner, B., & van den Anker, J. N. (2018). Management of anaphylaxis and allergies in patients with long QT syndrome: a review of the current evidence. Annals of Allergy, Asthma & Immunology, 121(5), 545-551.
  5. Craun, K. L., & Schury, M. P. (2020). Fexofenadine. StatPearls [Internet].