Usage
Bilastine is prescribed for the symptomatic relief of allergic rhinoconjunctivitis (both seasonal and perennial) and urticaria (hives). It falls under the pharmacological classification of second-generation antihistamines. Bilastine works by selectively blocking peripheral histamine H1 receptors. This action inhibits the effects of histamine, a chemical mediator released during allergic reactions, thereby reducing allergy symptoms.
Alternate Names
While “bilastine” is the established generic name, it’s marketed under various brand names, including Blexten, Bilaxten, and Ilaxten.
How It Works
Pharmacodynamics: Bilastine exerts its therapeutic effect by selectively antagonizing peripheral H1 receptors. It doesn’t bind to muscarinic receptors and demonstrates limited penetration into the central nervous system, resulting in a lower risk of sedation compared to first-generation antihistamines.
Pharmacokinetics:
- Absorption: Bilastine is rapidly absorbed after oral administration, reaching peak plasma concentration (Tmax) in approximately 1.13 hours. Food and fruit juices, especially grapefruit juice, can reduce its bioavailability.
- Metabolism: Bilastine undergoes minimal metabolism in the liver.
- Elimination: It is primarily eliminated unchanged through feces (approximately 67%) and urine (approximately 33%), predominantly via renal clearance. The mean elimination half-life is around 14.5 hours, allowing for once-daily dosing.
Mode of Action: Bilastine acts as a competitive antagonist at peripheral H1 receptors. It binds to these receptors, preventing histamine from binding and triggering the downstream cascade that leads to allergic symptoms.
Dosage
Standard Dosage
Adults: The standard dose for adults and adolescents 12 years and older is 20 mg (one tablet) once daily.
Children:
- 6-11 years (weighing at least 20 kg): 10 mg once daily, available as an orodispersible tablet or oral solution.
- Under 6 years: The safety and efficacy have not been established for children under 6.
Special Cases:
- Elderly Patients: No dose adjustment is necessary.
- Patients with Renal Impairment: No dose adjustment is needed.
- Patients with Hepatic Dysfunction: No dose adjustment is required as bilastine isn’t extensively metabolized in the liver.
- Patients with Comorbid Conditions: No specific dose adjustments mentioned for other diseases.
Clinical Use Cases:
Bilastine is not indicated for use in situations like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. Its primary indication is for managing allergic rhinoconjunctivitis and urticaria.
Side Effects
Common Side Effects:
Headache, dizziness, drowsiness, nausea, abdominal pain, dry mouth, fatigue.
Rare but Serious Side Effects:
Severe allergic reactions (anaphylaxis), QT prolongation, torsades de pointes (rare).
Long-Term Effects:
No specific long-term adverse effects have been identified.
Contraindications
- Hypersensitivity to bilastine.
- History of QT prolongation or torsades de pointes, including congenital long QT syndrome.
Drug Interactions
Bilastine may interact with:
- P-glycoprotein Inhibitors: (e.g., ketoconazole, erythromycin, cyclosporine, ritonavir, diltiazem) can increase bilastine plasma levels.
- Grapefruit juice and other fruit juices: May decrease bioavailability of bilastine.
Pregnancy and Breastfeeding
- Pregnancy: Limited data available; use with caution and only if clearly needed.
- Breastfeeding: Excretion in human breast milk is unknown; not recommended during breastfeeding.
Drug Profile Summary
- Mechanism of Action: Selective peripheral H1 receptor antagonist.
- Side Effects: Headache, dizziness, drowsiness, nausea, abdominal pain, dry mouth, and fatigue. Rarely QT prolongation and torsades de pointes.
- Contraindications: Hypersensitivity to bilastine, history of QT prolongation or torsades de pointes.
- Drug Interactions: P-glycoprotein inhibitors, grapefruit juice.
- Pregnancy & Breastfeeding: Use with caution in pregnancy; not recommended while breastfeeding.
- Dosage: Adults and adolescents ≥12 years: 20 mg once daily. Children 6-11 years (≥20 kg): 10 mg once daily.
- Monitoring Parameters: Monitor for any signs of hypersensitivity reactions or cardiac effects, especially in patients at risk for QT prolongation.
Popular Combinations:
No commonly recommended or specific combination therapies are available for Bilastine.
Precautions
- General Precautions: Assess for hypersensitivity, renal or hepatic impairment, and concomitant medications.
- Pregnant Women and Breastfeeding Mothers: Use cautiously or avoid during pregnancy and avoid during breastfeeding.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Bilastine?
A: Adults and adolescents ≥12 years: 20 mg once daily. Children 6-11 years (weighing ≥20 kg): 10 mg once daily.
Q2: How should Bilastine be administered?
A: Orally, with water, on an empty stomach, either one hour before or two hours after meals or fruit juice.
Q3: What are the common side effects of Bilastine?
A: Headache, dizziness, nausea, abdominal pain, dry mouth, fatigue, and drowsiness.
Q4: Can Bilastine be used during pregnancy?
A: Limited data are available, and it’s generally recommended to avoid use during pregnancy unless the benefits clearly outweigh the risks.
Q5: What are the contraindications for Bilastine?
A: Hypersensitivity to bilastine and a history of QT prolongation or torsades de pointes, including congenital long QT syndromes.
Q6: Does Bilastine interact with other medications?
A: Yes, it can interact with P-glycoprotein inhibitors (e.g., ketoconazole, erythromycin), increasing bilastine levels. Grapefruit juice may decrease bilastine absorption.
Q7: Can Bilastine impair driving ability?
A: Though less sedating than first-generation antihistamines, bilastine may cause drowsiness in some individuals, potentially affecting driving ability.
Q8: How does Bilastine work in the body?
A: It selectively blocks peripheral H1 receptors, preventing histamine from causing allergy symptoms.
Q9: Is Bilastine safe for elderly patients?
A: Yes, no dose adjustments are necessary in elderly patients.
Q10: What should patients do if they miss a dose of Bilastine?
A: Take the missed dose as soon as remembered, unless it is almost time for the next scheduled dose. Do not double the next dose.
