Singuair is used in mild to moderate asthma to decrease the symptoms of asthma and the number of acute asthma attacks. However, this medicine should not be used to relieve an asthma attack that has already started. This medicine is also used to treat the symptoms (sneezing, runny nose, itching, wheezing) of seasonal (short-term) allergies.

Special precautions

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For Singuair , the following should be considered:

Allergies— tell your doctor if you have ever had any unusual or allergic reaction to Singuair . Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy— Singuair has not been studied in pregnant women. However, it has been studied in animals and has not been found to cause birth defects or other problems. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding— It is not known whether Singuair passes into breast milk in humans. However, it does pass into breast milk in animals. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breast-feeding. Mothers who are using this medicine and who wish to breast-feed should discuss this with their doctor.

Children— No information is available regarding use of Singuair in infants younger than 12 months of age.

Older adults— many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults. There is no specific information comparing use of Singuair in the elderly with its use in other age groups. However, it has been used in some elderly patients and no differences in effectiveness or side effects were seen from those that occurred in younger adults.

Other medicines— although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your health care professional if you are taking or using any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other medical problems— the presence of other medical problems may affect the use of Singuair . Make sure you tell your doctor if you have any other medical problems, especially:

• Allergy to aspirin or non-steroidal anti-inflammatory agents (NSAIDs) (etodolac [e.g., Lodine], ibuprofen [e.g., Advil, Motrin], ketoprofen [e.g., Orudis], naproxen [e.g., Aleve])—Patients should continue to avoid aspirin or NSAIDs while taking montelukast.
• Liver disease—Effects of montelukast may be increased because of slower removal from the body
• Phenylketonuria (PKU)—the chewable tablets may contain aspartame, which can make your condition worse.

Side effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if the following side effect occurs:

•  Rare

• Pus in the urine 

•  Incidence not determined

• Abdominal or stomach pain;  anxiety;  assault;  attack;  bloating;  chills;  clay-colored stools;  constipation;  convulsions ;  darkened urine;  diarrhea ;  difficulty swallowing;  dry mouth;  fast, irregular, pounding, or racing heartbeat or pulse;  force;  general tiredness and weakness;  hives or welts;  hyperventilation;  indigestion;  irregular heartbeats;  irritability;  itching;  itching, puffiness, or swelling of the eyelids or around the eyes, face, lips or tongue;  itching skin;  large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, sex organs;  light-colored stools;  loss of appetite ;  loss of bladder control;  muscle spasm or jerking of all extremities;  nausea ;  nervousness;  pains in stomach, side, or abdomen, possibly radiating to the back;  redness of skin;  restlessness;  seeing, hearing, or feeling things that are not there;  shaking;  shortness of breath;  sudden loss of consciousness;  tightness in chest ;  trouble sleeping;  unpleasant breath odor;  upper right abdominal pain;  unusual tiredness or weakness;  vomiting ;  vomiting of blood;  wheezing ;  yellow eyes or skin 

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

•  More common

• Headache 

•  Less common

• Abdominal or stomach pain;  cough;  dental pain;  dizziness;  fever;  heartburn;  skin rash;  stuffy nose;  weakness or unusual tiredness 

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Keep all appointments with your doctor.

Don't let anyone else take your medicines.