How Long Does Allergy Medicine Take To Work?


How long for allergy medicine to work?

Every allergy medicine works differently. How long it takes for your allergy meds to work will depend on several factors, including the severity of your allergies, the type of allergy medicine you're taking, and how consistently you are taking the allergy medicine.

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If you have allergies, you might be familiar with the runny nose, itchy eyes, and general discomfort caused by allergies. When you finally get around to taking allergy medicine, you might wonder how long it will take for the medication to work.

Learn the ins and outs of allergy treatments, including the different types and the amount of time you can expect to wait for them to take full effect.

What Are the Different Types of Medications?

When it comes to allergy medications, there are two main types that can help to provide relief: those that primarily focus on temporarily managing the symptoms, usually over-the-counter (OTC) medications, and those that treat your allergies at the root cause to prevent future symptoms from occurring.

Over-the-Counter Medications

OTC medications are designed to relieve allergy symptoms that have already started. The most common types of OTC medications are antihistamines. Antihistamines work by blocking the release of histamine, a chemical released by the body in response to an allergen.

There are many OTC antihistamines available on the market, but the most popular include:


Zyrtec (Cetirizine) is a popular OTC antihistamine used to temporarily manage mild to moderate allergy symptoms like sneezing, congestion, and itching. It works by blocking the body's histamine receptors to prevent the release of the chemical that causes these symptoms. Zyrtec is available in several forms, including tablet, syrup, and liquid gel options.


Allegra (Fexofenadine) is another OTC option designed to treat mild to moderate allergy symptoms for short-term relief. It works very similarly to Zyrtec, with the main difference being that it comes in several dosages and strengths. Allegra is available in both 12-hour and 24-hour formulations. 


Xyzal (Levocetirizine) is an antihistamine used to manage common allergy symptoms like watery eyes, runny nose, itchy eyes, and sneezing. It works the same way as the medications above however has a slightly less drowsy effect. Xyzal is available in tablet form and should be taken once daily.   


Claritin (Loratadine) is another antihistamine available in both OTC and prescription forms. It's used to temporarily manage mild to moderate allergy symptoms such as stuffy nose, itchy eyes, and sneezing. Claritin is available in tablet, syrup, and liquid gel form and is usually used once daily.


Benadryl (Diphenhydramine) is one of the most well-known antihistamines on the market. It's an antihistamine used to manage the symptoms of mild to moderate allergic reactions and other conditions like hives, motion sickness, and even insomnia. While it's relatively effective, Benadryl is particularly likely to cause drowsiness.

How Long Does It Take for Antihistamines To Work?

There are two different groups of OTC antihistamines: first-generation and second-generation. First-generation antihistamines are the older generation of allergy medications while second-generation antihistamines are newer. The generation of medicines you choose will affect how quickly they start working and how long the effects last.

First-Generation Antihistamines

First-generation antihistamines typically take about 30 minutes to an hour to start working and last 4 to 6 hours. While they are effective in providing temporary allergy relief, they tend to cause side effects like drowsiness. The most popular first-generation antihistamine is Benadryl, but there are several other options available as well.

First-generation antihistamine medications include:

  • Benadryl (Diphenhydramine)
  • Chlorpheniramine
  • Brompheniramine
  • Tripelennamine

Second-Generation Antihistamines

Second-generation antihistamines are generally as effective as first-generation antihistamines but they tend to cause fewer side effects. In particular, second-generation antihistamines tend to be less sedating. These antihistamines typically take about 30 minutes to an hour to provide allergy relief and can last anywhere between 12 to 24 hours.

Second-generation antihistamine medications include:

  • Zyrtec (Cetirizine)
  • Allegra (Fexofenadine)
  • Xyzal (Levocetirizine)
  • Claritin (Loratadine)
  • Clarinex (Desloratadine)

Prescription Options

While OTC antihistamines can help temporarily manage symptoms, they are a short-term allergy solution. If you want long-term relief from your allergies, you need a treatment that treats the root cause of your allergy and doesn’t just mask your symptoms. Immunotherapy exposes the body to small doses of allergens to retrain your immune system to stop reacting when exposed to your allergies. Over time, your immune system becomes desensitized to your allergies, resulting in long-lasting allergy relief.

There are two main types of immunotherapy:

Allergy Shots

Subcutaneous immunotherapy (SCIT) was the first type of allergy immunotherapy. Commonly referred to as allergy shots, this therapy involves regularly injecting an extract containing trace amounts of an allergen, like pollen, under the skin over months to years. This therapy allows the immune system to become desensitized to the allergen and stop reacting when it’s exposed.

While allergy shots are effective, they can also be a time-consuming and painful process. Allergy shots must be administered at your doctor’s office and you are required to wait for 30 minutes afterward to make sure you don’t experience any severe allergic reactions.

Sublingual Immunotherapy

Sublingual immunotherapy (SLIT) is a type of immunotherapy that involves placing drops or tablets of an allergen extract under the tongue to slowly expose your immune system to your allergens. Eventually, your body becomes desensitized and stops reacting with allergy symptoms.

Sublingual immunotherapy is just as effective as allergy shots, however, they can also be taken safely from the comfort of your home and don’t require frequent trips to the doctor’s office or uncomfortable injections.

How Long Does It Take for Immunotherapy To Work?

Immunotherapy can be a very effective treatment for allergies, but it doesn't work immediately. It usually takes several months or years of regular therapy to make long-term changes to the immune system. Some people start seeing relief from their symptoms within the first few months or weeks of treatment.

The main factors at play here are the severity of the allergy and the type of immunotherapy being used. Some patients using sublingual immunotherapy experience relief as early as 6 weeks, and most patients note benefits around 6 months.

Why Is Sublingual Immunotherapy the Best Choice?

There are several reasons why sublingual immunotherapy is a popular alternative to allergy shots. Sublingual immunotherapy is frequently considered to be the best choice for immunotherapy because it is a safe and effective treatment while also being less expensive and more convenient than allergy shots.

Take Our Allergy Assessment

If you're struggling with allergies, sublingual immunotherapy may be your best treatment option. At Wyndly, our allergy doctors will create a personalized treatment plan to get you living free from your allergies.

Take our quick online assessment today to see if sublingual immunotherapy is right for you!

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