Usage
Ebastine + Phenylephrine is prescribed for the symptomatic relief of allergic rhinitis (hay fever) and the common cold. It helps relieve symptoms such as sneezing, runny nose, nasal congestion, watery eyes, and itching.
Pharmacological Classification:
- Ebastine: Second-generation antihistamine (H1 receptor antagonist/inverse agonist).
- Phenylephrine: Decongestant (α1-adrenergic receptor agonist).
Mechanism of Action: Ebastine works by blocking the action of histamine, a chemical released by the body during allergic reactions. Phenylephrine constricts blood vessels in the nasal passages, reducing swelling and congestion.
Alternate Names
No widely recognized alternate names exist for this specific combination. However, it’s important to note that numerous brand names exist under which this combination is marketed in different regions.
How It Works
Pharmacodynamics: Ebastine competes with histamine for binding to H1 receptors, primarily in peripheral tissues, thus reducing histamine’s effects like vasodilation, increased vascular permeability, and smooth muscle contraction. Phenylephrine stimulates α1-adrenergic receptors, causing vasoconstriction, which reduces nasal congestion.
Pharmacokinetics: Ebastine is rapidly absorbed after oral administration and is extensively metabolized in the liver, primarily by CYP3A4. Its major active metabolite is carebastine. Both ebastine and carebastine contribute to the antihistaminic effect. Phenylephrine is absorbed from the gastrointestinal tract but has limited bioavailability due to first-pass metabolism. It is primarily metabolized by monoamine oxidase (MAO) in the intestine and liver. Both drugs are eliminated primarily through renal excretion.
Mode of Action: Ebastine and carebastine act as inverse agonists or antagonists at the H1 receptor, stabilizing the receptor in its inactive conformation. This prevents histamine from binding and triggering downstream signaling pathways associated with allergic symptoms. Phenylephrine acts as an agonist at α1-adrenergic receptors on vascular smooth muscle, leading to vasoconstriction.
Receptor Binding, Enzyme Inhibition or Neurotransmitter Modulation: Ebastine and carebastine bind to H1 receptors. Phenylephrine binds to α1-adrenergic receptors. Phenylephrine is metabolized by MAO.
Elimination Pathways: Ebastine is metabolized by CYP3A4 in the liver. Both ebastine and its metabolites are eliminated primarily through renal excretion. Phenylephrine is metabolized by MAO and excreted mainly in the urine.
Dosage
Standard Dosage
Adults: 10 mg Ebastine + 10 mg Phenylephrine once daily.
Children (12 years and older): 10 mg Ebastine + 10 mg Phenylephrine once daily.
Children (under 12 years): Not generally recommended.
Special Cases:
- Elderly Patients: Start with a lower dose and adjust based on tolerability and clinical response.
- Patients with Renal Impairment: Dose adjustment may be necessary. Consult current guidelines and clinical judgment.
- Patients with Hepatic Dysfunction: Caution is advised. Dose adjustment may be required. Consult latest recommendations.
- Patients with Comorbid Conditions: Use with caution in patients with hypertension, diabetes, hyperthyroidism, cardiovascular disease, or prostatic hypertrophy. Close monitoring is recommended.
Clinical Use Cases
The combination of Ebastine + Phenylephrine is not typically used in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. Its primary use is for outpatient management of allergic rhinitis and common cold symptoms.
Dosage Adjustments
Dosage adjustments are based on age, renal and hepatic function, and other comorbid conditions as outlined above. Always consider patient-specific factors.
Side Effects
Common Side Effects:
- Drowsiness
- Headache
- Dry mouth
- Nausea
- Dizziness
Rare but Serious Side Effects:
- Allergic reactions (rash, itching, swelling, difficulty breathing)
- Tachycardia
- Palpitations
- Hypertension
- Hallucinations
Long-Term Effects:
No significant long-term effects have been reported with typical use.
Adverse Drug Reactions (ADR):
Serious ADRs are rare but can include severe allergic reactions and cardiovascular effects.
Contraindications
- Hypersensitivity to ebastine, phenylephrine, or any component of the formulation.
- Severe hypertension
- Coronary artery disease
- Narrow-angle glaucoma
- Monoamine oxidase inhibitor (MAOI) therapy (within 14 days)
- Pheochromocytoma
Drug Interactions
- MAOIs: Can cause a hypertensive crisis.
- Tricyclic antidepressants: May enhance anticholinergic effects.
- Beta-blockers: May lead to paradoxical hypertension.
- Other sympathomimetics: Additive effects may occur.
- Alcohol: May increase drowsiness and other CNS effects.
- Ketoconazole and other CYP3A4 inhibitors: May increase ebastine levels.
Pregnancy and Breastfeeding
Pregnancy: Safety has not been established. Use only if clearly needed and the potential benefit outweighs the risk to the fetus.
Breastfeeding: It is unknown whether ebastine or phenylephrine are excreted in human milk. Caution is advised.
Drug Profile Summary
- Mechanism of Action: Ebastine: H1 receptor antagonist/inverse agonist; Phenylephrine: α1-adrenergic receptor agonist.
- Side Effects: Drowsiness, headache, dry mouth, nausea, dizziness. Rarely: allergic reactions, tachycardia, hypertension.
- Contraindications: Hypersensitivity, severe hypertension, CAD, narrow-angle glaucoma, MAOI use, pheochromocytoma.
- Drug Interactions: MAOIs, tricyclic antidepressants, beta-blockers, other sympathomimetics, alcohol, ketoconazole.
- Pregnancy & Breastfeeding: Use with caution if benefits outweigh risks.
- Dosage: Adults and children over 12: 10 mg ebastine + 10 mg phenylephrine once daily.
- Monitoring Parameters: Blood pressure, heart rate, allergy symptoms.
Popular Combinations
No regularly recommended combinations exist. Ebastine + Phenylephrine is generally used as a stand-alone therapy.
Precautions
- Use cautiously in patients with hypertension, diabetes, hyperthyroidism, cardiovascular disease, or prostatic hypertrophy.
- Avoid alcohol.
- May cause drowsiness; avoid driving or operating machinery.
- Caution in elderly patients and those with renal or hepatic impairment.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Ebastine + Phenylephrine?
A: Adults and children 12 years and older: 10 mg ebastine + 10 mg phenylephrine once daily.
Q2: How does Ebastine + Phenylephrine work?
A: Ebastine blocks histamine action, while phenylephrine reduces nasal congestion by constricting blood vessels.
Q3: What are the common side effects?
A: Drowsiness, headache, dry mouth, nausea, dizziness.
Q4: Can I take this medication if I am pregnant or breastfeeding?
A: Consult your doctor as safety hasn’t been definitively established.
Q5: What are the major contraindications for this drug?
A: Hypersensitivity, severe hypertension, CAD, narrow-angle glaucoma, MAOI use, pheochromocytoma.
Q6: Are there any significant drug interactions I should be aware of?
A: Yes, significant interactions exist with MAOIs, tricyclic antidepressants, and certain other medications. Consult your doctor.
Q7: Can I drink alcohol while taking Ebastine + Phenylephrine?
A: It is advisable to avoid alcohol as it can increase drowsiness and other side effects.
Q8: Should I avoid driving while taking this medication?
A: Use caution as it may cause drowsiness, especially initially.
Q9: What should I do if I miss a dose?
A: Take the missed dose as soon as you remember, unless it is almost time for your next dose. Do not double the dose.
