Singulair

DRUG DESCRIPTION

Montelukast sodium, the active ingredient in SINGULAIR, is a selective and orally active leukotriene receptor antagonist that inhibits the cysteinyl leukotriene CysLT1 receptor.

Montelukast sodium is described chemically as [R-(E)]-1-[[[1-[3-[2-(7-chloro-2quinolinyl)ethenyl]phenyl]-3-[2-(1-hydroxy-1-methylethyl)phenyl]propyl]thio]methyl]cyclopropaneacetic acid, monosodium salt.

The empirical formula is C35H35ClNNaO3S, and its molecular weight is 608.18. The structural formula is:

SINGULAIR® (montelukast sodium)  Structural Formula Illustration

Montelukast sodium is a hygroscopic, optically active, white to off-white powder. Montelukast sodium is freely soluble in ethanol, methanol, and water and practically insoluble in acetonitrile.

Each 10-mg film-coated SINGULAIR tablet contains 10.4 mg montelukast sodium, which is equivalent to 10 mg of montelukast, and the following inactive ingredients: microcrystalline cellulose, lactose monohydrate (89.3 mg), croscarmellose sodium, hydroxypropyl cellulose, and magnesium stearate. The film coating consists of: hydroxypropyl methylcellulose, hydroxypropyl cellulose, titanium dioxide, red ferric oxide, yellow ferric oxide, and carnauba wax.

Each 4-mg and 5-mg chewable SINGULAIR tablet contains 4.2 and 5.2 mg montelukast sodium, respectively, which are equivalent to 4 and 5 mg of montelukast, respectively. Both chewable tablets contain the following inactive ingredients: mannitol, microcrystalline cellulose, hydroxypropyl cellulose, red ferric oxide, croscarmellose sodium, cherry flavor, aspartame, and magnesium stearate.

Each packet of SINGULAIR 4-mg oral granules contains 4.2 mg montelukast sodium, which is equivalent to 4 mg of montelukast. The oral granule formulation contains the following inactive ingredients: mannitol, hydroxypropyl cellulose, and magnesium stearate.

What are the possible side effects of montelukast (Singulair)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

  • skin rash, bruising, severe tingling, numbness, pain, muscle weakness;
  • mood or behavior changes, anxiety, depression, or thoughts about suicide or hurting yourself;
  • tremors or shaking;
  • severe sinus pain, swelling, or irritation; or
  • worsening asthma...

Read All Potential Side Effects and See Pictures of Singulair »

What are the precautions when taking montelukast sodium (Singulair)?

Before taking montelukast, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this drug, tell your doctor or pharmacist your medical history, especially of: liver disease.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

The chewable tablets may contain aspartame. If you have phenylketonuria (PKU) or any other condition that requires you to limit/avoid aspartame (or phenylalanine) in your diet, ask your doctor or pharmacist about using this medication...

Read All Potential Precautions of Singulair »


Singulair Consumer (continued)

SIDE EFFECTS: Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these rare but serious side effects occur: mental/mood changes (such as agitation, aggression, anxiety, trouble sleeping, abnormal dreams, sleep-walking, depression, hallucinations, thoughts of harming yourself/suicide), numbness/tingling/shooting pain in the arms or legs, muscle weakness.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking montelukast, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this drug, tell your doctor or pharmacist your medical history, especially of: liver disease.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

The chewable tablets may contain aspartame. If you have phenylketonuria (PKU) or any other condition that requires you to limit/avoid aspartame (or phenylalanine) in your diet, ask your doctor or pharmacist about using this medication safely.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is unknown if this medication passes into breast milk. Consult your doctor before breast-feeding.


Singulair Patient Information Including Side Effects

Brand Names: Singulair

Generic Name: montelukast (Pronunciation: mon the LOO kast)

  • What is montelukast (Singulair)?
  • What are the possible side effects of montelukast (Singulair)?
  • What is the most important information I should know about montelukast (Singulair)?
  • What should I discuss with my healthcare provider before taking montelukast (Singulair)?
  • How should I take montelukast (Singulair)?
  • What happens if I miss a dose (Singulair)?
  • What happens if I overdose (Singulair)?
  • What should I avoid while taking montelukast (Singulair)?
  • What other drugs will affect montelukast (Singulair)?
  • Where can I get more information?

What is montelukast (Singulair)?

Montelukast is a leukotriene (loo-koe-TRY-een) inhibitor. Leukotrienes are chemicals your body releases when you breathe in an allergen (such as pollen). These chemicals cause swelling in your lungs and tightening of the muscles around your airways, which can result in asthma symptoms.

Montelukast is used to prevent asthma attacks in adults and children as young as 12 months old. It is also used to relieve runny nose and sneezing caused by allergies in adults and children as young as 6 months old.

Do not give this medication to a child without a doctor's advice.

Montelukast is also used to prevent exercise-induced bronchoconstriction (narrowing of the air passages in the lungs) in people who are not already taking this medicine for other conditions.

If you already take this medication to prevent asthma or allergy symptoms, do not use it for exercise-induced bronchoconstriction.

Montelukast may also be used for other purposes not listed in this medication guide.

What are the possible side effects of montelukast (Singulair)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

  • skin rash, bruising, severe tingling, numbness, pain, muscle weakness;
  • mood or behavior changes, anxiety, depression, or thoughts about suicide or hurting yourself;
  • tremors or shaking;
  • severe sinus pain, swelling, or irritation; or
  • worsening asthma symptoms.

Less serious side effects may include:

  • headache;
  • stomach pain, heartburn, upset stomach, nausea, diarrhea;
  • tooth pain;
  • tired feeling;
  • fever, stuffy nose, sore throat, cough, hoarseness; or
  • mild rash.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is the most important information I should know about montelukast (Singulair)?

Do not use montelukast to treat an asthma attack that has already begun. It will not work fast enough to reverse your symptoms. Use only a fast-acting inhalation medication to treat an asthma attack. Talk with your doctor if any of your asthma medications do not seem to work as well in treating or preventing asthma attacks.

It may take up to several weeks of using this medicine before your symptoms improve. For best results, keep using the medication as directed. Talk with your doctor if your symptoms do not improve after several weeks of treatment.

Call your doctor right away if you feel that this medicine is not working as well as usual, or if it makes your condition worse. If it seems like you need to use more of any of your medications in a 24-hour period, talk with your doctor.

If you already take this medication to prevent asthma or allergy symptoms, do not use it for exercise-induced bronchoconstriction.

Call your doctor at once if you have any mood or behavior changes, anxiety, depression, or thoughts about suicide or hurting yourself.

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