Medically reviewed by Jessica Swirble, PharmD
Last updated on 6/18/2024

Drug Information | Side Effects | Use & Dosage | Request a Prescription

The use of montelukast can lead to various side effects in some individuals.

Common mild side effects of montelukast use include:

• Headache
  
• Dizziness
  
• Fatigue
  
• Stomach pain
  
• Heartburn
  
• Diarrhea
  
• Cough
  
  

More severe side effects include:

• Signs of an allergic reaction (hives, skin rash, difficulty breathing)
  
• Signs of an infection (fever, chills, body aches, numbness or “pins and needles” in the arms or legs)
  
• Ear pain or fever in children
  
• Blistering or peeling skin
  
• Elevated liver enzymes
  
• Worsening pulmonary symptoms
  
• Mood or behavior changes
  
  

If you experience any severe or concerning side effects while taking montelukast, contact your healthcare provider right away.

Inform your healthcare provider about any existing medical conditions, allergies, or other medications you are taking before starting treatment with montelukast. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with montelukast.

Tell your provider if you are taking these medications or supplements:

• Gemfibrozil
  
• Phenobarbital and rifampin
  
• Adasuve inhalation
  
  

You should also mention medical conditions such as:

• Mental health conditions
  
• Asthma
  
• Liver disease
  
• A history of severe allergic reactions after taking an NSAID (like aspirin)
  
• Phenylketonuria
  
• Alcoholism
  
  

If you are pregnant, planning to become pregnant, or breastfeeding, discuss the potential risks and benefits of using montelukast with your healthcare provider.

Take montelukast exactly as prescribed by your healthcare provider. Do not exceed the recommended dose or duration of treatment.

Your provider may direct you to take montelukast in the evening for asthma or at the same time each day for allergic rhinitis to maximize its effectiveness.

Montelukast can cause dizziness. Do not drive or operate machinery until you know how this medication affects you.

Montelukast can cause potentially serious behavioral changes, including suicidal thoughts and behaviors. If you experience any mood-related or behavioral changes, notify your healthcare provider immediately.

Complete the full course of treatment, even if you feel better, to ensure the medication's effectiveness in managing your condition.

In case of a montelukast overdose, seek medical attention immediately. Symptoms of overdose may include stomach pain, drowsiness, thirst, headache, vomiting, or hyperactivity. If you suspect an overdose, contact the poison control helpline at 1-800-222-1222 or call emergency services.