How Long Does It Take for Allergy Medicine to Work?

When allergy symptoms hit, relief can’t come soon enough. Whether you’re dealing with sneezing, congestion, itchy eyes, or a runny nose, you want to know how long does it take for allergy medicine to work — and which options will provide the fastest relief. The answer depends on the type of allergy medication you take, how your body responds, and the severity of your symptoms. Most allergy medicines work within 30 minutes to 2 hours, while nasal sprays take a few days, and allergy shots may take months for full effect.

How Quickly Different Allergy Medications Work

Not all allergy medications work at the same speed. Some provide relief within minutes, while others take days or even weeks to reach their full effect. Here’s what to expect from common types of allergy treatments:

1. Antihistamines: Fast Relief for Sneezing, Itching, and Runny Nose

Antihistamines are one of the most commonly used allergy medications, blocking histamine — the chemical that triggers allergy symptoms.

Oral Antihistamines (e.g., Zyrtec, Claritin, Allegra, Benadryl):

• How fast they work: 30 minutes to 2 hours
• How long they last: 4 to 24 hours, depending on the type
• Best for: Seasonal allergies, hay fever, pet allergies

Quick Tip: Second-generation antihistamines like Zyrtec and Allegra work faster and last longer than older options like Benadryl, which can cause drowsiness.

Antihistamine Eye Drops (e.g., Pataday, Zaditor):

• How fast they work: Within minutes
• How long they last: Up to 12 hours
• Best for: Itchy, red, and watery eyes caused by allergens

Antihistamine Nasal Sprays (e.g., Astelin, Astepro):

• How fast they work: Within 15 to 30 minutes
• How long they last: 12 to 24 hours
• Best for: Nasal congestion and post-nasal drip

2. Nasal Steroid Sprays: Long-Term Relief for Congestion

Nasal corticosteroid sprays help reduce inflammation in the nasal passages, making them highly effective for congestion and sinus pressure.

• Examples: Flonase, Nasacort, Rhinocort, Nasonex
• How fast they work: 6 to 12 hours for some relief, but the full effect takes a few days to a week
• How long they last: Up to 24 hours per dose
• Best for: Chronic nasal congestion, seasonal allergies, year-round allergies

Quick Tip: If you have persistent allergy symptoms, start using nasal sprays a few days before allergy season begins for the best results.

3. Decongestants: Fast Relief for Stuffy Nose and Sinus Pressure

Decongestants shrink swollen blood vessels in the nasal passages, helping you breathe more easily.

• Examples: Sudafed (pseudoephedrine), Afrin (oxymetazoline)
• How fast they work: 15 to 30 minutes
• How long they last: 4 to 12 hours, depending on the type
• Best for: Short-term relief of nasal congestion

Caution: Decongestant nasal sprays like Afrin should not be used for more than three days in a row, as they can cause rebound congestion.

4. Immunotherapy: Long-term Allergy Treatment

Allergy shots and sublingual immunotherapy help desensitize your immune system to allergens over time.

• How fast they work: Initial improvement within 3 to 6 months, full effect within 1 to 3 years
• How long they last: Long-term relief, even after stopping treatment
• Best for: Severe allergies, long-term allergy control

Quick Tip: If your allergy symptoms are persistent and medication isn’t enough, immunotherapy may be a good long-term option.

How to Get the Best Results from Allergy Medicine

To ensure your allergy medication works as effectively as possible:

• Take It Before Symptoms Start: If you have seasonal allergies, start taking medication a few days before pollen counts rise.
• Be Consistent: Some medications, like nasal steroids, need to be taken daily for best results.
• Check for Interactions: Some allergy medicines don’t mix well with other medications. Talk to your doctor or pharmacist if you take multiple medications.
• Identify Your Triggers: Understanding what’s causing your allergies can help you choose the right treatment.

When to See an Allergist

If your allergy symptoms persist despite taking medication, or if your allergies significantly impact your daily life, it may be time to consult an allergist. An allergy specialist can help determine the best treatment plan, whether that’s adjusting your medication, conducting allergy testing, or considering immunotherapy.

Find the Right Allergy Treatment at Northeast Allergy

If you’re wondering how long does it take for allergy medicine to work or which one is best for you, visit Northeast Allergy. Our specialists can help you find the right treatment plan for fast and effective relief. Whether you need allergy testing, prescription medications, or long-term options like immunotherapy, we’re here to help.

Click here to request an appointment today and breathe easier with expert allergy care!