Yes — for most people, GLP-1 medications for weight loss (Ozempic, Wegovy, Mounjaro, Zepbound) can be safely taken together with allergy medications, including antihistamines, nasal sprays, inhalers, and allergy drops (SLIT). There are no major drug interactions between GLP-1 meds and common allergy treatments.
However, GLP-1 drugs may cause nausea and delayed stomach emptying, which can affect how some oral medicines are absorbed. If your allergies worsen, or you use multiple medications, speak with an allergist.

Quick Answer: Can You Combine GLP-1 Weight-Loss Drugs and Allergy Medicines?

Short answer: Yes. Most GLP-1 medications — including Ozempic® (semaglutide), Wegovy®, Mounjaro® (tirzepatide), and Zepbound® — can be taken with:

• oral antihistamines (cetirizine, loratadine, fexofenadine)
• nasal steroid sprays (fluticasone, mometasone)
• asthma inhalers
• leukotriene modifiers (montelukast)
• allergy drops (SLIT)
• allergy shots
• decongestants (with some caution)

Current AAAAI and NIH guidance show no known harmful interactions between these drug classes.

Deep Guide: GLP-1 Meds + Allergy Treatments — What You Need to Know

What are GLP-1 medications?

GLP-1 receptor agonists are medications used for:

• weight loss
• type 2 diabetes
• metabolic health

They slow stomach emptying, stabilize blood sugar, and decrease appetite. Examples:

• Ozempic®
• Wegovy®
• Rybelsus® (oral)
• Mounjaro®
• Zepbound®

These medications don’t directly affect the immune system or allergic inflammation.

Do GLP-1 meds reduce or worsen allergies?

There is no evidence that GLP-1 meds make allergies better or worse.
However, some patients report:

Possible reasons symptoms may fluctuate:

• Weight loss reduces reflux, which can help chronic cough.
• Improved sleep and lower inflammation may help asthma.
• Nausea, reflux, or vomiting from GLP-1 meds can mimic allergy symptoms.

But the medications do not biologically impact allergy pathways (IgE, mast cells, eosinophils).

Which Allergy Medications Are Safe with GLP-1 Drugs?

Below is a breakdown of compatibility.

1. Oral Antihistamines (Zyrtec, Claritin, Allegra)

Safe with GLP-1 meds.
No known interactions.
If you take daily antihistamines, continue as usual.

Possible note:
Because GLP-1 drugs slow stomach emptying, you may absorb pills a little slower — but this is not harmful.

2. Nasal Steroid Sprays

Fluticasone, nasal mometasone, budesonide — all safe.
They work locally, not systemically.

3. Nasal Antihistamine Sprays (Azelastine, Olopatadine)

Fully compatible.
These do not interact with GLP-1 pathways.

4. Asthma Inhalers

Includes Albuterol, Symbicort, Advair, Trelegy, and inhaled steroids.

All safe to use with GLP-1 medications.

5. Montelukast (Singulair)

Safe — no interactions known.
However, montelukast carries mood-related warnings from the FDA.
Discuss with your allergist if you develop anxiety, sleep changes, or irritability.

6. Allergy Drops (SLIT) — At-Home Immunotherapy

Completely safe with GLP-1 medications.

SLIT allergy drops (such as HeyPak® from HeyAllergy) are placed under the tongue, absorbed through the oral mucosa, and do not rely on stomach absorption — making them ideal for patients on GLP-1 drugs.

Learn more:
👉 Allergy Drops (SLIT)

7. Allergy Shots (SCIT)

Safe with GLP-1 medications.

AAAAI guidance shows no contraindication with GLP-1 meds.

8. Decongestants (Pseudoephedrine, Phenylephrine)

Generally safe, BUT:

• may raise heart rate
• may worsen GLP-1 nausea
• use with caution in people with heart disease or anxiety

If you need frequent decongestants, you likely need an allergist evaluation.

Are GLP-1 Meds and Allergy Meds OK Together?

Can GLP-1 Meds Affect How Allergy Medicines Work?

Not significantly — but there are a few situations to note:

Delayed stomach emptying

GLP-1 medications slow digestion.
This may:

• delay the onset of oral allergy pills
• increase nausea if you take many pills at once
• affect oral medications that require precise absorption (rare)

Best practices:

• Take allergy pills with water.
• Separate from large meals.
• Spread out medications if you experience nausea.

If symptoms still break through, an allergist can customize a plan.

Why SLIT Allergy Drops Are a Strong Option for People on GLP-1 Meds

SLIT (sublingual immunotherapy) is increasing in popularity because:

• it treats the root cause of allergies
• it is safer than shots (per AAAAI guidelines)
• it can be done completely at home
• it bypasses the stomach and therefore is not affected by delayed gastric emptying
• HeyAllergy tailors SLIT formulas to patient testing and triggers

Learn more:
👉 Start Allergy Drops

When to See an Allergist (Important Signs)

You should schedule a visit if you have:

Allergic Rhinitis / Sinus Symptoms

• daily congestion
• persistent post-nasal drip
• sinus infections 2+ times/year
• loss of smell
• symptoms affecting sleep or exercise

Asthma Symptoms

• wheezing
• night cough
• needing rescue inhaler 2+ times/week
• chest tightness
• shortness of breath

Medication Concerns

• needing frequent decongestants
• unclear triggers
• worsening symptoms after starting GLP-1 meds
• poor control despite multiple medications

✔️ Book a same-week telehealth appointment:
👉 Schedule Allergy Consultation

✔️ Explore at-home treatment options:
👉 Allergy Drops (SLIT)

What To Do Next (Action Box)

Frequently Asked Questions (FAQ)

1. Can I take Ozempic or Mounjaro with Zyrtec?
‍Yes. No interaction is known. Most patients can take daily antihistamines with GLP-1 medications.

2. Do GLP-1 meds make allergies worse?
‍Not directly. They don’t affect allergic inflammation. But nausea, reflux, or fatigue can overlap with allergy symptoms.

3. Are allergy shots safe with Wegovy or Zepbound?
‍Yes — AAAAI guidelines show no contraindication.

4. Are SLIT allergy drops safe while on GLP-1 meds?
‍Yes. SLIT works under the tongue and does not rely on stomach absorption.

5. How do I know if my allergies are out of control?
‍If you need daily meds, experience chronic congestion, or have asthma symptoms more than twice weekly — you should see an allergist.

‍

If allergies impact your daily life — congestion, fatigue, headaches, or asthma flare-ups — we can help.
HeyAllergy’s board-certified allergists offer fast telemedicine visits, insurance-friendly care, and personalized SLIT allergy drops delivered to your door.

👉 Book your online allergy appointment today

Author, Review & Disclaimer

Author: Krikor Manoukian, MD, FAAAI, FACAAI — Board-Certified Allergist/Immunologist
Bio: Dr. Manoukian is a board-certified allergist/immunologist specializing in telemedicine-enabled allergy care and personalized SLIT programs. He leads HeyAllergy’s clinical team and trains providers in safe immunotherapy.
Medical Review: HeyAllergy Clinical Team (Board-Certified Allergists/Immunologists)
Disclaimer: This article is educational and not a substitute for personalized medical advice. Always consult your clinician about your medications and treatment options.

References

• AAAAI Ask-the-Expert: No absolute contraindication to allergy immunotherapy with antidepressants or other medications.
• AAAAI/ACAAI Sublingual Immunotherapy Practice Parameter Update (2017).
• NIH/NIAID: Allergic Rhinitis and Asthma data and guidance.
• CDC: Asthma medication safety.