House dust mite allergen extract belongs to the class of medications called allergy immunotherapy. It is used to treat moderate-to-severe allergy symptoms such as sneezing, itchy, stuffy or runny nose caused by house dust mite allergy. Before treatment with house dust mite allergen extract, your doctor will confirm your allergy with either a skin or a blood test.

This medication works by causing the body's immune system to become less sensitive to the effects of the dust mites. It may take between 8 and 14 weeks of using this medication regularly, before symptoms begin to improve. This medication does not provide immediate relief for symptoms of house dust mite allergy.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended adult dose of this medication is 1 tablet, taken once daily by letting it dissolve under the tongue.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

To take the tablet, carefully remove the tablet from the foil packaging with dry hands. Place the tablet under your tongue and allow it to dissolve. Try not to swallow for 1 minute after placing the tablet under your tongue. Avoid eating and drinking anything for 5 minutes after taking the medication. Wash your hands after handling the tablet.

It is important to take this medication exactly as prescribed by your doctor.

If you miss a dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children. Leave the tablets in the original foil packaging until you are ready to take a dose. This will protect the tablet from moisture in the air.

Each white to off-white, circular sublingual tablet, debossed with a pentagon on one side, contains 12 SQ-HDM of standardized house dust mites allergen extract from D. farina and D. pteronyssinus. Nonmedicinal ingredients: gelatin NF (fish source), mannitol USP and sodium hydroxide NF. Lactose-free.

Do not take this medication if you:

• are allergic to any of the non-drug ingredients in this medication
• have previously had a severe or life-threatening reaction to house dust mite immunotherapy
• have unstable, severe asthma
• are taking beta-blockers (e.g., propranolol, metoprolol)
• have inflammatory conditions of the mouth, such as severe yeast infection, or recent removal of teeth
• have had an allergic reaction that caused inflammation of the esophagus (tube leading from the mouth to the stomach)

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• itching ears or mouth
• nausea
• swollen tongue
• throat irritation
• tingling or burning mouth

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• chest pain
• difficulty swallowing
• heartburn
• hives
• itching all over the body
• mouth or lips swelling
• pain swallowing
• throat swelling

Stop taking the medication and seek immediate medical attention if any of the following occur:

• asthma attack
• symptoms of a severe allergic reaction (e.g., dizziness, fainting, fast or weak heartbeat, throat tightness, stomach cramps, vomiting, diarrhea, wheezing, shortness of breath)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergic Reactions: Severe and potentially life-threatening allergic reactions are possible when using house dust mite allergen extract. Before you take house dust mite allergen extract, inform your doctor about any previous adverse reactions you have had to medications, especially medications used to treat grass allergies. Contact your doctor at once if you experience signs of an allergic reaction, such as skin rash, itching, difficulty breathing or swelling of the face and throat.

Milder allergic reactions such as hives, itching, mouth itchiness, runny nose, and throat irritation can occur with the use of this medication. If these side effects become bothersome, discuss your concerns with your doctor.

Asthma: This medication may cause asthma symptoms or cause existing asthma symptoms to worsen. If you have a history of asthma, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. People with uncontrolled asthma should not use this medication.

First dose: Severe allergic reactions have occurred with the first dose of this medication. For this reason, the first dose should be taken at your doctor's office or a similar location where emergency treatment is available if the medication causes a severe reaction. Your doctor will likely want you to remain in the office for at least 30 minutes after taking the dose, to ensure that it does not cause a severe allergic reaction.

Oral surgery: If you are going to have tooth removal or oral surgery, this medication should be stopped until complete healing of the mouth has occurred. If your treatment has been interrupted for more than 15 days, then this medication should be restarted at your doctor's office, under medical supervision.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if house dust mite allergen extract passes into breast milk. If you are breast-feeding and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children less than 12 years of age.

Seniors: The safety and effectiveness of using this medication have not been well studied.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.