Side Effects of Singulair

Side Effects of Singulair
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What Is Singulair?

Singulair, also called montelukast sodium, is a leukotriene inhibitor. It helps the body ward off asthma and hay fever symptoms by blocking substances called leukotrienes. Leukotrienes are associated with allergic responses in the body that cause the body to have swelling and tightening sensations in muscles, such as when the throat closes during an asthma attack.

Dosage and Interactions

Singulair is taken once a day, with or without food, and most doctors prescribe it as an evening dose. The dosage depends on age. Adults and children over the age of 15 will take a 10mg tablet every evening with water. Children ages 6 to 14 can take a chewable tablet, which is 5mg. Singulair also comes in granules, which is advised for young children between the ages of 2 to 5 and is dosed at 4 mg. The granules can be taken directly in the mouth or mixed in food such as applesauce. Children under the age of 2 should have the dosage decided by their pediatricians.

Make sure to tell your doctor or pharmacist if you are taking Phenobarbital or an antibiotic called Rifampin that may cause a reduced blood level of Singulair; however, dosage does not need adjustment. Taking Singulair along with prednisone may increase the adverse effects of the steroid medication.

Cautions When Using Singulair

This medication is used as an adjunct therapy along with other asthma and allergy drugs. It will not stop an asthma attack, so rescue inhalers should be kept in reach if needed. Always alert your doctor or pharmacist of the other medications and even over-the-counter drugs and herbs you are taking to avoid interactions. Do not take aspirin or other non-steroidal anti-inflammatory (NAIDS) if they trigger asthma attacks, because Singulair offers no protection against NSAID-related asthma attacks. Patients should have routine blood tests to check liver enzymes. People who have liver disorders, including cirrhosis, may need lower doses of this medication.

Possible Side Effects of Singulair

The most common side effect of Singulair is headaches. Others may feel stomach upset, nausea, vomiting, abdominal pain, weakness, and diarrhea. These symptoms may subside after your body adjusts to the medication. Less common symptoms may include trouble sleeping, drowsiness, irritability, and dream abnormalities. If you acquire dizziness, cough, stuffy nose, rash, fever, tingling of the hands/feet, and flu-like symptoms, notify your doctor immediately. If you feel really sick, go to the emergency room.

In 2009, the Food and Drug Administration reviewed Singular and other leukotriene inhibitors for neuropsychiatric problems. There were post market cases of agitation, aggression, anxiety, hallucinations, depression, tremor, and suicidal thoughts. Although rare, the FDA must disclose this information as an update to the precaution sections of the drug insert and in the Physician’s Desk Reference.

Overdose and Conclusion

In the event of an overdose, call the poison control center immediately at 1-800-222-1222. Symptoms to watch out for are extreme thirst, drowsiness, dilated pupils, unusual muscle movements, and abdominal pain.

When taking new medications, always be on the lookout for unusual feelings. Report any side effects of Singulair to your doctor, and wait for information on continuing or stopping this drug.


Medications and Drugs: Singulair

FDA U.S. Food and Drug Administration:

The Pill Book - 13th Edition: by Harold M. Silverman, Pharm. D. [Bantam Books, 2008] pp. 626-630

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