Singulair Side Effects

Generic name: montelukast

Note: This document contains side effect information about montelukast. Some of the dosage forms listed on this page may not apply to the brand name Singulair.

Some side effects of Singulair may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to montelukast: oral granule, oral tablet, oral tablet chewable

Get emergency medical help if you have any of these signs of an allergic reaction while taking montelukast (the active ingredient contained in Singulair) hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have a serious side effect such as:

• 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;

• easy bruising, unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin;

• severe sinus pain, swelling, or irritation;

• worsening asthma symptoms; or

• severe skin reaction -- fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Less serious side effects of montelukast 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.

For Healthcare Professionals

Applies to montelukast: oral granule, oral tablet, oral tablet chewable

Nervous system

Nervous system side effects have included headache (18% to 20%) and dizziness (2%). Isolated and rare reports of somnolence have been associated with the use of higher than recommended doses. Seizures have been reported very rarely. Paresthesias, hypoesthesia, and drowsiness and have been reported in postmarketing experiences.

Respiratory

Respiratory system side effects have included influenza (4%), cough (3%), and nasal congestion (2%). In some studies, upper respiratory tract infection (28%) and worsened asthma (4% to 11%) were associated with the use of this drug. However, many patients with asthma have some or all of these symptoms, and a causal relationship has not been proven. Rhinorrhea, sinusitis, otitis, influenza, epistaxis, and pneumonia have also been reported.
Postmarketing reports have included thoracic and mediastinal disorders.

Gastrointestinal

Gastrointestinal side effects have included abdominal pain, dyspepsia, or infectious gastroenteritis in up to 3% of patients. Diarrhea has been associated with the use of higher than recommended doses.
Postmarketing reports have included vomiting.

General

In general, montelukast (the active ingredient contained in Singulair) is well tolerated. Asthenia, fatigue, or fever has been associated with the use of this drug in approximately 2% of patients. Varicella has also been reported.

Dermatologic

Dermatologic side effects have included rash, eczema, urticaria, and dermatitis. Postmarketing experience has included erythema multiform.
Postmarketing reports include Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN).

Churg-Strauss syndrome has been reported in association with montelukast therapy.

Hepatic

Hepatic side effects have included elevated hepatic serum transaminases in approximately 2% of patients. Pancreatitis has been reported very rarely. Jaundice with elevated liver enzymes are described in a 42 year old man several months after starting montelukast (the active ingredient contained in Singulair) therapy. Serum enzymes completely normalized 4 months after drug withdrawal.

Postmarketing experience has reported rare cases of cholestatic hepatitis, hepatocellular liver injury and mixed pattern liver injury.

Other

Other side effects have included isolated cases of Churg-Strauss syndrome, a rare systemic vasculitis associated with asthma.

Churg-Strauss syndrome is a rare granulomatous eosinophilic condition that involves the upper and lower airways and manifests as rhinitis, sinusitis and asthma. If untreated the syndrome may progress to systemic vasculitis, peripheral neuropathy and potentially fatal cardiac complications. In most cases, the condition emerged during withdrawal of oral corticosteroid therapy. A causative role for leukotriene receptor antagonists has not been ruled out.

Musculoskeletal

Musculoskeletal side effects have included myalgia, muscle cramps, and muscle aches. Postmarketing experience has reported arthralgia.

Hematologic

Hematologic side effects have included increased bleeding tendencies and bruising. Thrombocytopenia has also been reported.

Ocular

Ocular side effects have included conjunctivitis.

Psychiatric

Psychiatric side effects have included agitation including aggressive behavior and hostility, anxiousness, dream abnormalities and hallucinations, depression, insomnia, irritability, restlessness, suicidal thinking and behavior (including suicide), and tremor.
Postmarketing reports include disorientation, insomnia, and somnambulism.

Hypersensitivity

Hypersensitivity side effects have included anaphylaxis, erythema nodosum, pruritus, urticaria, and very rarely hepatic eosinophilic infiltration. Postmarketing reports have included angioedema.

Cardiovascular

Postmarketing reports have included palpitations and edema.

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