Also called Montelukast, Singulair is used to decrease the symptoms of asthma and the number of acute asthma attacks. It is an antiasthmatic, leukotriene receptor antagonist. Because of how it works, though, Singulair should not be used to relieve an asthma attack that has already started. Singulair is sometimes used to treat the symptoms of seasonal allergies.
Be sure to tell your doctor of any allergies you have whether it is to medication or food, preservatives, or dyes. Also tell your doctor of any other medications you are taking, including vitamins and supplements, and any medical conditions you may have.
Avoid alcohol when taking this medicine.
It is very important that you take this medicine exactly as your doctor tells you to. Do not take more or less medicine than directed, and don’t stop taking Singulair without discussing it with your doctor first.
If you miss a dose of this medicine, take it as soon as you remember, unless it is almost time for your next dose. Do NOT double doses.
Check with your doctor as soon as possible if the following side effect occurs: pus in the urine; 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; or yellow eyes or skin.
Montelukast sodium is described chemically as [R-(E)]-1-[[[1-[3-[2-(7-chloro-2-quinolinyl) 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. 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.
Singulair has the following structural formula: