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Aspirin Desensitization

image - North Texas Allergy & Asthma Associates

What is AERD?

AERD stands for Aspirin Exacerbated Respiratory Disease. We estimate ten percent (10%) of adults with asthma and forty percent (40%) of asthmatic patients with nasal polyps have AERD. This is an adult onset condition with three cardinal features:

•Nasal Polyps (Polypoid rhinosinusitis)
•Asthma
•Respiratory reactions to aspirin (ASA) and nonsteroidal anti-inflammatory drugs (NSAIDS)

Many patients with AERD are difficult to treat with respect to their sinus disease and asthma often requiring surgery every one to three years to treat rapid re-growth of nasal polyps and suffering multiple asthma exacerbations per year. The polyps cause severe nasal obstruction, loss of sense of smell, and uncontrolled asthma. 

What causes AERD?

Nobody knows for sure, however patients with AERD seem to have an acquired overproduction and sensitivity to chemicals known as leukotrienes.  Even though patients may once have been able to take aspirin, they are now unable to take it without causing a sudden asthma attack or other allergic symptoms.  The aspirin sensitivity doesn�t explain the whole picture, however.  Even while avoiding aspirin, these patients continue to have asthmatic symptoms, nasal congestion, formation of nasal polyps and repeated sinus infections.

What treatments exist for AERD?

In a community setting, the typical treatment is repeated sinus surgeries, avoidance of ASA and NSAIDS and treatment of asthma.  Even with optimal therapy and avoidance of ASA/NSAIDS, the disease is often sub-optimally controlled with rapidly recurring polyps and frequent asthma exacerbations.
Alternatively, aspirin desensitization and therapy combined with surgery is a well-recognized therapeutic option for patients with AERD, particularly those with severe asthma and/or severe polyp disease. This procedure has several benefits described below. 

Why is aspirin desensitization and therapy not widely available?

There are few institutions and clinicians around the country that will perform aspirin desensitization. A good desensitization program requires asthma and allergy specialists with substantial clinical experience, enthusiasm, and infrastructure support to perform the aspirin challenges and desensitization. This typically requires training or experience that is not widely available.

Who discovered this procedure?

In 1979, researchers at the Scripps Clinic in La Jolla, CA began studying aspirin sensitivity in asthmatic patients. To their surprise, they noticed that with each successive dose of aspirin, the severity of the aspirin reactions lessened. In fact, after several small doses of aspirin, the allergic reaction disappeared altogether. Under carefully controlled challenges, the patients were gradually able to take full adult-strength doses of aspirin (650mg).
At this point, they were said to be "desensitized" to aspirin. With continued daily ASA therapy, the patients reported less nasal congestion, fewer nasal polyps, better asthma control and less sinusitis. Many patients also experienced an improvement in their sense of smell. Through several follow-up studies, it has been conclusively shown that this procedure reduces upper and lower respiratory inflammation in part by altering the patients leukotriene levels and sensitivity to leukotrienes.

What is entailed in aspirin desensitization?

During the aspirin desensitization, you will receive small incremental doses of aspirin, usually starting with approximately 1/20th of the therapeutic dose, so as to minimize the risk of a serious reaction. Doses are gradually escalated depending on your tolerance. Once a reaction occurs, it will be treated and the following day you will return for continuation of the desensitization procedure. Repeat and escalating doses depending on tolerance are continued until you are able to ingest 325 mg of ASA without reaction, depending on your individual case. The procedure generally takes 2 days but in rare cases may take longer.

How successful is aspirin desensitization?

Clinical studies have shown that aspirin desensitization followed by daily aspirin use reduces symptoms of asthma, nasal polyps and sinusitis.  Approximately 87% of patients experienced improvement in their symptoms and were able to reduce their use of steroids and/or other medications.

What is aspirin therapy?

After desensitization, you will be instructed to continue taking 325 mg to 650 mg of aspirin twice daily depending on your case.

Am I a candidate for aspirin desensitization?

Candidates for aspirin desensitization and treatment must fall into one of three categories:

•Aspirin sensitive patients with asthma who are experiencing uncontrolled respiratory inflammation despite optimal medical management, or who are requiring unacceptably large doses of corticosteroids.
•Aspirin sensitive patients requiring repeated polypectomies and/or sinus surgeries.
•Aspirin sensitive patients who need ASA or NSAIDS for the treatment of other diseases, such as arthritis or blood clots.

Who is not an aspirin desensitization candidate?

Aspirin / NSAID desensitization is not indicated for patients:

•Who has ASA / NSAID induced hives (urticaria) or swelling (angioedema) affecting the airway
•Who have ASA/NSAID induced anaphylactic shock
•Who are pregnant

What are the potential benefits associated with aspirin desensitization and treatment?

Aspirin desensitization candidate patients may experience the following benefits:

• Decreased corticosteroid doses
•Improved asthma control
•Fewer nasal polypectomies and/or sinus surgeries
•Tolerance to ASA AND NSAIDS
•Improved sense of smell

What are the risks associated with the aspirin desensitization procedure?

Since the doses given are usually much smaller that you have taken, in almost all cases, the reactions are no greater and usually less severe than the reaction you may have experienced previously when taking a full therapeutic dose. The most serious risk during the desensitization procedure is the development of a life threatening asthma exacerbation.  Other symptoms may include nasal congestion, profuse runny nose, tightness of the throat, flushing of the skin, hives, and rarely a drop in blood pressure.
Our physicians and staff will closely monitor your physical status, vital signs, oxygen saturation and lung function (FEV1) for 3 hours after each dose looking for any reaction. When a reaction occurs, the procedure will be stopped and the symptoms will be treated with one or more inhalation treatments, nasal sprays, oral medications, and/or injections of medications to relieve the symptoms. Aspirin desensitization should never be performed outside a medical facility.

What are the risks associated with long-term aspirin treatment?

Long-term risks from aspirin include pain or bleeding of the stomach or stomach ulcers. Aspirin slows down blood clotting, so you may bleed longer if you cut yourself or have surgery. Once you are desensitized to aspirin, the risks of daily aspirin are small. If you take it with food, stomach problems are less likely. Taking an antacid, such as Maalox or Mylanta can lessen stomach pain.  Coated aspirin tablets that bypass the stomach before they dissolve are also recommended.  There are additional medicines that could be prescribed if needed.  If you start bleeding anywhere in your body, you should call us immediately and refrain from taking any further aspirin.

What do I need to do prior to aspirin desensitization?

Understand that aspirin desensitization must be conducted in a medical setting equipped to handle life threatening asthma attacks. You should also be prepared to devote a week to the procedure. Although the desensitization may be completed in two days, it may take longer. We aim to schedule the desensitization immediately after sinus surgery/nasal polypectomy for optimal results and to limit your time off from work or school. To ensure the utmost safety, you must not be ill and your asthma must be controlled.

For the one week prior to desensitization, your asthma must be stable on all of your usual asthma controller medications but on NO MORE THAN 10 mg of PREDNISONE PER DAY. This will be reflected by peak expiratory flow rates (Peak Flows) within 80% - 100% of your personal best with no greater than 20 % variability. Peak flow measurements should be taken daily every 2 hours from 8 AM to 6PM and recorded for the few days prior to your desensitization. Your doctor will want to see this before beginning the desensitization. You will need to avoid ALBUTEROL or any short acting bronchodilator for at least 8 hours before and during desensitization. Use of long acting bronchodilators, (e.g. Serevent, Foradil), should be continued.

Your doctor may also recommend medications that will help block the clinical effects of those Leukotrienes (Singulair, Accolate, or Zyflo).  These medications should be continued during the procedure.  You should also continue all other medications recommended by your physician.  The medications that we would like you to hold 2 days prior to the aspirin desensitization is anti-histamines (Claritin/loratadine, Zyrtec/cetirizine, Allegra/fexofenadine, Xyal, Clarinex, Benadryl, etc) and decongestants.  

How long will it take?

The aspirin desensitization takes the full day over two to three days.  Expect to arrive at 07:45 AM or 9:00 AM as directed by the medical staff.  Since you are here for the whole day please bring books, laptop, snacks (no dietary restrictions) and/or other activities.
Remember:

•Have a light breakfast the morning of the procedure
•Continue all regular medications as scheduled unless otherwise directed (beta-blockers may be asked to be held)
•No anti-histamines or decongestants 48 hours prior to arrival
•Continue all asthma medications but we would like you to refrain from Albuterol or any other short acting bronchodilator 8 hours prior to procedure.

What do I need to do after aspirin desensitization?

You need to continue your daily dose of aspirin.  We recommend Ecotrin or other coated aspirin to help lessen the effects of stomach irritation.  In time you will slowly notice improvement of your asthma and nasal symptoms.  Tapering of medications will be done on a regular basis.   Typically the doctor will see you back one month after completing the aspirin desensitization. 

Once desensitized to aspirin, you are most likely desensitized to several other non-steroidal anti-inflammatory drugs (NSAID - Motrin, Naprosyn, etc).  Thus, if you are desensitized to aspirin and are taking it regularly you can take the NSAID medication but do not exceed the recommended dose. 

What treatment will I be on following aspirin desensitization?

Once desensitized and on long term aspirin treatment, desensitization is maintained only as long as you continue to take uninterrupted aspirin doses.  Aspirin should not be discontinued without speaking to your allergist.

 

What if I miss a dose, am I still desensitized?

Once desensitized, your body can tolerate one day without aspirin. If you forget to take your aspirin and remember within 48 hours since your most recent dose, simply take your usual dose.  After 48 hours of a missed dose, your body begins to lose the desensitized state. You should NOT consider yourself desensitized after missing a dose for 48 hours or more. If you take aspirin then, you could have a reaction. Call your doctor for instructions if a dose is missed for 48 hours or more.

What about aspirin and elective surgery?

Have your allergist discuss a safe method to avoid discontinuing aspirin with you and your surgeon.
Below is a common recommendation (but clear it with your surgeon first):

•Decrease aspirin dose to 325 mg each day, beginning 8 days before surgery
•Two days before surgery, take your last aspirin tablet in the morning.
•On the day before surgery and the morning of surgery DO NOT take any aspirin
•After completing the operation and when you are completely recovered from anesthesia, take one 325 mg aspirin tablet
•On the day after surgery (post op day 1), take one 325 mg tablet of aspirin in the morning and one 325 mg at night.
•On the second day after surgery (post op day 2) take your usual dose of aspirin (resume pre-op aspirin regimen).