Most sleep aids are safe to combine with non-drowsy allergy medications like loratadine, cetirizine, and fexofenadine. But combining sleep aids with sedating allergy meds (like Benadryl) can cause excess drowsiness, breathing issues, and next-day impairment. Melatonin is generally safe with allergy meds, while diphenhydramine-based sleep aids should be used cautiously. If you’re unsure, talk to a board-certified allergist or schedule an online visit at HeyAllergy.

Quick Guide: Are Sleep Aids Safe With Allergy Meds?

Safe combinations (most adults)

• Melatonin + non-drowsy antihistamines (Claritin, Zyrtec, Allegra): Safe
• Melatonin + nasal sprays (Flonase, Nasonex): Safe
• Melatonin + allergy drops (SLIT): Safe
• Herbal sleep aids + non-drowsy antihistamines: Usually safe

Use caution

• Benadryl + sleep aids (diphenhydramine OR doxylamine): Not recommended
• Unisom + sedating allergy meds: Avoid
• Magnesium + sedating meds: May increase drowsiness
• Asthma + prescription sedatives: Use only with clinician guidance

Deep Guide: How Sleep Aids Interact With Allergy Medications

Allergy symptoms—especially nasal congestion and post-nasal drip—can make it hard to fall asleep. Many adults reach for sleep aids, but combining them with allergy medicines can sometimes magnify drowsiness or affect breathing.

Below is a simple guide based on the most common categories.

Melatonin and Allergy Medications

Melatonin is the safest sleep aid to combine with allergy medicines.

Safe combinations include:

• Melatonin + Claritin
• Melatonin + Zyrtec
• Melatonin + Allegra
• Melatonin + Flonase/Nasonex
• Melatonin + Montelukast (Singulair)
• Melatonin + SLIT allergy drops (Sublingual Immunotherapy):
  → No known interaction, based on AAAAI guidance on SLIT safety.

Why melatonin is usually safe:
It works on sleep-wake cycles, not on histamine pathways, and does not depress breathing.

Use caution if:

• You take high doses (>5 mg)
• You have uncontrolled asthma
• You combine it with prescription sedatives

Antihistamine Sleep Aids (Benadryl, Unisom) and Allergy Meds

Most OTC sleep aids contain diphenhydramine or doxylamine.
These are also sedating antihistamines, which means combining them with allergy meds can be risky.

Diphenhydramine (Benadryl)

Benadryl is both an allergy med and an OTC sleep aid.
Symptoms of oversedation can occur if doubled up.

Avoid combining:

• Benadryl (for allergies) + Unisom (doxylamine)
• Benadryl (for allergies) + Benadryl-based sleep aids
• Benadryl (for allergies) + Nyquil Zzz formulations

Risks include:

• Extreme drowsiness
• Slowed breathing
• Next-day impairment
• Increased risk of falls
• Worsened nighttime asthma symptoms

Doxylamine (Unisom)

Doxylamine is also a sedating antihistamine.

Avoid combining with:

• Benadryl
• Chlorpheniramine
• Hydroxyzine

Safer alternative:
Use a non-drowsy antihistamine during the day and melatonin at night.

Herbal Sleep Aids and Allergy Meds

Herbal supplements may seem harmless, but some interact with allergy meds or asthma.

Magnesium glycinate

Generally safe with allergy meds, but can increase sedation when combined with:

• Benadryl
• Hydroxyzine
• Doxylamine

Chamomile tea

Safe with antihistamines, though people with ragweed allergies may rarely notice throat itching.

Valerian root

May intensify sedative effects. Use caution with:

• Benadryl
• Unisom
• Any prescription sedative

L-theanine

Safe with all allergy meds, including SLIT.

Prescription Sleep Meds (Ambien, Trazodone, Benzodiazepines)

These medications should be used cautiously if you have allergies or asthma.

Safe with non-drowsy allergy meds:

• Ambien (zolpidem)
• Trazodone
• Lunesta

Use caution with sedating allergy meds:

• Benadryl
• Doxylamine
• Hydroxyzine

For asthma patients

Prescription sedatives can:

• Depress nighttime breathing
• Reduce airway muscle tone
• Make nocturnal asthma worse

If asthma keeps you awake, this is a signal to see a board-certified allergist online at HeyAllergy.

Decision Table — What You Can and Cannot Combine

When to See an Allergist

See a board-certified allergist if you notice any of these:

Symptoms suggesting unsafe combinations

• Trouble waking up
• Slowed breathing at night
• Severe morning grogginess
• Worsened nighttime asthma
• Chest tightness after taking sleep aids

Symptoms suggesting allergies—not insomnia—are the real issue

• Congestion every night
• Post-nasal drip
• Sneezing or itchy eyes in bed
• Coughing when lying down
• Trouble sleeping during pollen season

If allergies are the root cause, treating the allergy, not masking symptoms with sleep aids, is the safest long-term fix.

➡ You can schedule an online visit at HeyAllergy.

Long-Term Solution: SLIT (Allergy Drops) May Improve Sleep Naturally

Many adults use sleep aids because allergies flare at night.

SLIT (sublingual immunotherapy) — also known as allergy drops — can reduce:

• Chronic nasal congestion
• Nighttime coughing
• Post-nasal drip
• Allergy-induced asthma symptoms

The AAAAI notes strong evidence for SLIT’s safety when prescribed correctly.

Learn more: HeyPak® Allergy Drops

What to Do Next

If you’re unsure whether your sleep aid is safe with your allergy meds:

Book a quick online appointment with a board-certified allergist.

If allergies affect your sleep every night:

Consider allergy drops (SLIT) — medicine that treats the root cause:

FAQs

1. Can I take melatonin with allergy medicine?
‍Yes. Melatonin is safe with Claritin, Zyrtec, Allegra, Flonase, and allergy drops. Avoid mixing it with prescription sedatives without medical guidance.

2. Is Benadryl safe as a sleep aid if I already took allergy medication?
‍Not always. Benadryl plus another sedating medication (Unisom, hydroxyzine) can cause oversedation. Avoid doubling up.

3. Can sleep aids make asthma worse?
‍Yes. Sedatives may reduce nighttime breathing strength. Use melatonin instead of sedatives if you have asthma, or talk to an allergist.

4. Are herbal sleep aids safe with allergy medications?
‍Most are safe with non-drowsy antihistamines. Use caution with magnesium glycinate and valerian root when taking sedating allergy meds.

5. How do I know if my insomnia is caused by allergies?
‍Symptoms like nighttime congestion, post-nasal drip, coughing, or throat clearing suggest allergic rhinitis. Treat the allergy—not the sleep—with SLIT or guided treatment.

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: Antidepressants and Allergy Shots — “No absolute contraindication” to AIT.
• AAAAI/ACAAI, Sublingual Immunotherapy Practice Parameter Update (2017).
• NIH/NIAID: Allergic Rhinitis guidance and pharmacologic safety.
• CDC: Nonprescription medication safety and sedation risks.