How Do Leukotriene Receptor Antagonists Work?

Leukotriene receptor antagonists are medications used to treat inflammatory respiratory conditions such as asthma and allergic rhinitis. Leukotriene receptor antagonists relieve the symptoms of asthma and allergic rhinitis by preventing leukotriene-induced inflammation, swelling of airways, excess mucus secretion and airway constriction.

Asthma and rhinitis episodes are triggered by allergens or exercise when the immune system releases inflammatory substances to attack what it perceives as foreign to the body. Cysteinyl leukotrienes are a group of inflammatory molecules released by immune cells such as mast cells, eosinophils, basophils and macrophages in the airway.

Cysteinyl leukotrienes trigger bronchial constriction and inflammation by activating protein molecules known as CysLT1 receptors on the surface of bronchial smooth muscle cells and immune cells in the airway. Cysteinyl leukotrienes promote inflammatory processes which include:

• Migration and aggregation of other immune cells in the airway which further promote inflammation.
• Greater permeability of small blood vessels (capillaries), which allows inflammatory proteins and immune cells to leak out.
• Contraction of the airway smooth muscles.

Leukotriene receptor antagonists prevent inflammation by binding to the CysLT1 receptors and blocking cysteinyl leukotrienes from stimulating them. Leukotriene receptor antagonists block the activity of three types of cysteinyl leukotrienes, LTC4, LTD4 and LTE4.

Leukotriene receptor antagonists are oral tablets or granules used in the treatment of the following conditions:

• Prevention and maintenance treatment of chronic asthma
• Exercise-induced bronchospasm
• Perennial allergic rhinitis
• Seasonal allergic rhinitis

Side effects of leukotriene receptor antagonists may include the following:

• Headache
• Abdominal pain
• Laryngitis (inflammation of the larynx)
• Pharyngitis (throat inflammation)
• Wheezing
• Viral infection
• Nausea
• Diarrhea
• Vomiting
• Dyspepsia (indigestion)
• Gastritis
• Gastroenteritis
• Influenza
• Dental pain
• Generalized pain
• Back pain
• Weakness
• Dizziness
• Myalgia (muscle pain)
• Malaise
• Fever
• Eczema
• Elevated liver enzymes
• Cholestatic hepatitis (liver inflammation due to impaired bile flow), rare
• Liver injury
• Nasal congestion
• Bronchitis (inflammation of the bronchial passage)
• Sinusitis (inflammation of the sinuses)
• Cough
• Upper respiratory infection
• Otitis (ear infection/inflammation)
• Allergic granulomatous angiitis/Churg-Strauss syndrome (a rare respiratory disease)
• Hypersensitivity reactions such as:
  • Rash
  • Urticaria (hives)
  • Pruritus (itching)
  • Angioedema (swelling in the tissue under the skin or mucous membranes)
  • Erythema multiforme (round lesions like bullseye)
  • Erythematous nodosum (painful bumps under the skin)
  • Hepatic eosinophilic infiltration
• Eosinophilia (high level of eosinophils in the blood)
• Eosinophilic pneumonia
• Pulmonary eosinophilia
• Vasculitis (blood vessel inflammation)
• Increased bleeding tendency/bleeding
• Bruising
• Thrombocytopenia (low platelet count)
• Epistaxis (nasal bleeding)
• Edema
• Agitation
• Anxiety
• Aggression and hostility
• Depression
• Disorientation
• Hallucinations
• Dream abnormalities
• Insomnia
• Somnambulism (sleepwalking)
• Restlessness
• Tic
• Irritability
• Suicidal thinking and behavior
• Obsessive-compulsive disorders
• Tremor
• Drowsiness
• Paresthesia (skin prickling sensation)
• Hypesthesia (loss of sensation)
• Dysphemia (stuttering)
• Seizures
• Palpitations
• Arthralgia (joint pain)
• Myalgia (muscle pain)
• Muscle cramps

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of leukotriene receptor antagonists include:

• Accolate
• montelukast
• Singulair
• zafirlukast