NULL is a fixed-dose combination medication containing Bilastine, a non-sedating H1 antihistamine, and Montelukast, a leukotriene receptor antagonist. This combination is highly effective for managing symptoms of allergic rhinitis (seasonal and perennial allergies) and is also used as an add-on therapy for the long-term management of mild to moderate asthma and chronic idiopathic urticaria (hives). By targeting two distinct chemical pathways responsible for allergic inflammation (Histamine and Leukotrienes), NULL provides superior relief from symptoms like sneezing, runny nose, congestion, and itching, with minimal risk of drowsiness.

NULL is a prescription combination medicine that contains Bilastine and Montelukast. It is commonly prescribed for the treatment of allergic rhinitis (such as hay fever, sneezing, runny nose, and itchy eyes) and as maintenance therapy in asthma. This medicine is not intended for quick relief of sudden asthma attacks but works to control symptoms over time.

Bilastine is a second‑generation antihistamine belonging to the piperidine derivative class. It works by selectively blocking histamine H1 receptors in the body, which helps reduce allergy symptoms like itching, nasal congestion, and watery eyes. Montelukast is a leukotriene receptor antagonist that blocks CysLT1 receptors. By doing so, it prevents airway inflammation, swelling, and narrowing of the airways, making breathing easier for patients with asthma. Together, these two medicines provide dual action against both allergic and asthmatic symptoms.

NULL is usually taken once daily. For best absorption, Bilastine should be taken on an empty stomach, either one hour before or two hours after food or fruit juice. Consistent daily use is important, even on days when symptoms are not present, as it is a maintenance medication.

This medicine is generally well-tolerated, but some patients may experience side effects such as headache, dizziness, stomach upset, or dry mouth. Rarely, Montelukast has been associated with mood changes, sleep disturbances, or depression. Patients should report any unusual symptoms to their doctor immediately. NULL should be used with caution during pregnancy and breastfeeding, and only under medical supervision.

NULL is indicated for the symptomatic management and maintenance treatment of:

Seasonal Allergic Rhinitis (SAR):

Relief from associated nasal (sneezing, itching, rhinorrhea, congestion) and ocular (watery, red, itchy eyes) symptoms.

Perennial Allergic Rhinitis (PAR):

Control of year-round allergic symptoms caused by persistent environmental triggers.

Chronic Idiopathic Urticaria (CIU):

Reduction in the severity and frequency of hives and associated pruritus (itching).

Asthma Prophylaxis:

Used as an alternative or add-on controller therapy for the long-term management of mild to moderate persistent asthma, particularly in patients sensitive to aspirin or those whose primary trigger is exercise (Exercise-Induced Bronchoconstriction).

Synergistic Efficacy:

The combination of H1 blockade and leukotriene inhibition provides a stronger anti-allergic and anti-inflammatory response than either medication used alone, effectively addressing both immediate and delayed-phase allergic reactions.

Comprehensive Symptom Relief:

Treats a wide range of symptoms, including nasal (congestion, sneezing) and dermal (hives, itching) symptoms, and improves lung function markers in asthma patients.

Non-Sedating Profile:

Bilastine is a third-generation antihistamine resulting in minimal central nervous system penetration and a low incidence of drowsiness, allowing normal daily activities.

Convenient Once-Daily Dosing:

The long half-life of both active ingredients supports single daily dosing, improving patient adherence to the treatment plan.

When taken as directed, NULL is generally well-tolerated. Side effects are typically mild and transient.

Common Side Effects (Usually Mild and may resolve with continued use):

• Headache

• Somnolence (sleepiness, low frequency)

• Dizziness

• Fatigue

• Dry mouth

• Gastrointestinal upset (abdominal pain, nausea)

Serious Side Effects (Stop taking the medicine and seek urgent medical attention if you experience):

• Neuropsychiatric Events (Montelukast Warning): While rare, Montelukast can cause serious changes in mood and behaviour. Seek immediate medical attention if you experience agitation, aggression, anxiety, vivid dreams, tremors, depression, insomnia, or thoughts of self-harm or suicide.

• Severe Allergic Reaction (Anaphylaxis): Rash, swelling of the face, tongue, or throat, or difficulty breathing.

• Hepatotoxicity: Signs of liver problems (yellowing of the skin or eyes, dark urine, persistent nausea, or upper right abdominal pain).

• Eosinophilia/Vasculitis (Churg-Strauss Syndrome): Development of rash, worsening lung symptoms, heart complications, and/or numbness/tingling in the extremities (rarely seen in patients reducing oral corticosteroids while on Montelukast).

• Dosing Schedule: Take one tablet once daily, or exactly as prescribed by your doctor.

• Timing: The tablet is usually taken in the evening to cover the night and morning peak of allergy/asthma symptoms.

• Administration: Swallow the tablet whole with water.

• Bilastine-Specific Rule (CRITICAL): Bilastine absorption is significantly reduced by food, especially grapefruit juice. Take NULL one hour before or two hours after consuming food or fruit juices. Water is the only recommended beverage.

• Acute Asthma: This medicine is for prevention and long-term control only. Do not use NULL to treat a sudden, acute asthma attack. Always use your prescribed rescue inhaler for acute symptoms.

NULL simultaneously tackles the inflammatory cascade by blocking the effects of two key chemical mediators released during an allergic response:

1. Bilastine (H1 Antagonist): When an allergen enters the body, immune cells (mast cells) release histamine. Histamine binds to H1 receptors, causing immediate symptoms like sneezing, runny nose, and itching. Bilastine selectively binds to and blocks the peripheral H1 receptors, preventing histamine from triggering these immediate symptoms.
2. Montelukast (Leukotriene Receptor Antagonist): Immune cells also release leukotrienes (specifically the cysteinyl leukotrienes, LTC4, LTD4, and LTE4). These chemicals bind to CysLT1 receptors on target cells, causing inflammation, tightening of the bronchial muscles, and excess mucus production. Montelukast selectively blocks the CysLT1 receptors, thereby reducing inflammation, relieving nasal congestion, and improving airflow in the lungs.

• Timing Is Important: Take Bilastine on an empty stomach. For best results, swallow the tablet either 1 hour before eating or 2 hours after eating or drinking fruit juice.

• Be Consistent: If prescribed for asthma or allergic rhinitis, take the medicine every day. It is a maintenance treatment and should be continued even when you do not have symptoms.

• Asthma Safety: This medicine is not a substitute for your quick‑relief inhaler. Always keep your rescue inhaler with you for sudden asthma symptoms.

• Monitor Mood and Behaviour: Pay attention to changes in mood, sleep, or behaviour. This is especially important in children and adolescents. Report any concerns to your doctor immediately.

• Manage Dry Mouth: If you experience dry mouth, drink plenty of water or use sugar‑free lozenges or candies to ease discomfort.

Store NULL in its original blister pack at room temperature (between 20°C and 25°C / 68°F and 77°F). Keep the medicine away from moisture, direct sunlight, and excessive heat to maintain its effectiveness. Always store out of reach of children and pets to prevent accidental ingestion.

Food & Juices (Major Interaction): Food, especially high-fat meals, and fruit juices (like grapefruit, orange, or apple juice) can significantly decrease the absorption and effectiveness of Bilastine. Take the tablet separately from food/juice as directed in the "How to Use" section.

Alcohol: Avoid excessive alcohol intake, as it may enhance potential side effects like dizziness.

Caution is advised in patients with:

• Kidney or Liver Impairment: Although Bilastine is mostly eliminated unchanged, and Montelukast is metabolised by the liver, dose adjustments may be necessary in cases of severe impairment.

• Asthma: This medicine should not be used as monotherapy for persistent asthma. It must be combined with appropriate primary asthma control therapy.

• Phenylketonuria (PKU): Some Montelukast formulations (chewable tablets) contain aspartame, which is a source of phenylalanine and should be avoided in PKU patients.

• Erythromycin/Ketoconazole: The concurrent use of these drugs can potentially increase the plasma concentrations of Bilastine. Use with caution.

• Rifampicin: May decrease the efficacy of Montelukast by inducing liver enzymes that metabolise it.

• CNS Depressants: While Bilastine is non-sedating, caution is needed when combining with other central nervous system (CNS) depressants, as additive effects are still possible.

The standard daily dose for adults and adolescents (15 years and older) is one tablet (Bilastine + Montelukast) taken once daily. This dose should not be exceeded. The precise duration of therapy will be determined by the treating physician based on the patient's condition (e.g., seasonal vs. perennial rhinitis or chronic asthma).

In case of an overdose, seek emergency medical attention immediately. Symptoms of overdose may include headache, nausea, abdominal pain, excessive thirst, excessive movement (hyperkinesia), or excessive drowsiness. Treatment is typically supportive and symptomatic.

If you miss a dose of NULL, take it as soon as you remember. If it is already time for your next scheduled dose, skip the missed dose entirely and continue with your regular once-daily schedule. Do not take a double dose to make up for the missed one.