Montelukast belong to a class of drugs known as leukotriene inhibitors. Leukotrienes are chemical substances in the body that are associated with the inflammation, constriction of airway muscles and fluid accumulation in the lungs. These things happen in asthma attack wherein there is widespread bronchospasm or tightening of the muscles around air passages. Montelukast is used to treat allergies and also prevent asthma attacks. However, montelukast will not stop an asthma attack that has already started.
To get the most benefit out of this drug, use montelukast on a regular basis. It may take some time before you get the maximum effect of this medication. If you notice that you require more than your usual amount of any asthma medication in a 24-hour period then inform your doctor. An increased need for montelukast could be an early sign of a serious asthma attack. Avoid any activity that may trigger an asthma attack.
Special precautions before taking this medicine are those patients with hepatic impairment and with phenylketonuria. You may need special monitoring and dosage adjustment in these conditions while under treatment with montelukast. Montelukast is not expected to be harmful to an unborn baby. It is also not known to pass into breast milk. However, do not take this medication without first telling your doctor if you are pregnant or could become pregnant and if you are breast-feeding.
Do not take a double dose of this medication. Just follow your doctor’s instructions on how to take montelukast which is usually taken in the evening. Although symptoms of montelukast overdose are unknown, seek emergency consult if you think you take too much of this medicine.
If you experience any of the following serious side effects, stop taking montelukast and seek emergency medical attention: an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives); numbness, tingling, or pain; a rash or unexplained open sores or bruising; flu-like illness; severe pain and swelling of the sinuses; or worsening respiratory symptoms.
Other, less serious side effects may be more likely to occur such as: upset stomach, stomach pain, or heartburn; dizziness or headache; tiredness; sore throat or cough, or nasal irritation. Inform your doctor about any other unusual side effect that is not listed above.
Drugs that may interact with montelukast are the following: rifampin (Rimactane, Rifadin) and phenobarbital (Luminal, Solfoton). You may not be able to take montelukast, or you may require a dosage adjustment or special monitoring during your treatment. Some other drugs may also interact with montelukast. Before taking any prescription or over-the-counter medicines, including herbal products and vitamins make sure to discuss it first with your doctor.
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, 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.
Montelukast has the following structural formula: