Azelastine

What Does Azelastine Do?

Azelastine is an antihistamine medication used to relieve hayfever and allergy symptoms such as nasal congestion, sneezing, and itchy nose by blocking histamine receptors, available as a nasal spray or eye drops.

How Does Azelastine Work? (the complicated stuff!)

Azelastine functions as a selective antagonist of histamine H1-receptors, primarily blocking the action of histamine released from mast cells in response to allergens. This action prevents histamine from binding to H1-receptors on nerve endings and other cells, thereby alleviating symptoms like itching, sneezing, and nasal congestion. Additionally, azelastine exhibits mast cell-stabilising properties, inhibiting the release of various inflammatory mediators, such as interleukin-6 and TNF-alpha, further contributing to its effectiveness in managing allergic reactions.

Drug Type and Category of Azelastine

Azelastine is an antihistamine medication primarily classified as a selective H1-receptor antagonist. 

What dosage of Azelastine should you be taking?

NICE Guidelines ¹

For Seasonal Allergic Rhinitis:

• Adults and Adolescents (12 years and older):
• 0.1% Nasal Spray: Administer 1 or 2 sprays in each nostril twice daily.
• 0.15% Nasal Spray: Administer 1 or 2 sprays in each nostril twice daily, or 2 sprays in each nostril once daily.
• Children (6 to 11 years):
• 0.1% or 0.15% Nasal Spray: Administer 1 spray in each nostril twice daily.
• Children (2 to 5 years):
• 0.1% Nasal Spray: Administer 1 spray in each nostril twice daily.

For Perennial Allergic Rhinitis:

• Adults and Adolescents (12 years and older):
• 0.15% Nasal Spray: Administer 2 sprays in each nostril twice daily.
• Children (6 months to 11 years):
• 0.1% Nasal Spray: Administer 1 spray in each nostril twice daily.

For Vasomotor Rhinitis:

• Adults and Adolescents (12 years and older):
• 0.1% Nasal Spray: Administer 2 sprays in each nostril twice daily.

Important Administration Instructions:

• Priming the Spray: Before initial use, prime the nasal spray by releasing 4 sprays or until a fine mist appears. If the spray has not been used for 3 or more days, re-prime with 2 sprays or until a fine mist appears.
• Usage: Azelastine nasal spray is for intranasal use only. Avoid spraying into the eyes.
• Storage: Store at controlled room temperature (20° to 25°C or 68° to 77°F) and protect from freezing.

What are the side-effects of Azelastine?

Common Side Effects

These are usually mild and resolve with continued use:

1. Nasal Spray:
• Bitter taste (dysgeusia), especially if the spray runs down the throat.
• Drowsiness or fatigue.
• Headache.
• Nasal irritation or burning sensation.
• Dry mouth or throat.
• Sneezing after application.
2. Eye Drops:
• Temporary stinging or burning sensation in the eyes.
• Eye redness or irritation.
• Dry eyes or watery eyes.

Less Common Side Effects

These may require medical attention if persistent or severe:

• Nosebleeds (epistaxis).
• Nausea.
• Dizziness.
• Cough or sore throat.
• Changes in taste or smell.

Rare but Serious Side Effects

Seek immediate medical attention if any of the following occur:

1. Allergic Reactions:
• Rash, itching, or swelling (especially of the face, tongue, or throat).
• Severe dizziness.
• Difficulty breathing.
2. Central Nervous System Effects:
• Severe drowsiness or confusion, especially if combined with alcohol or sedatives.
3. Eye Drops Specific:
• Blurred vision or increased sensitivity to light (photophobia).

Precautions

1. Drowsiness:
• Azelastine may cause drowsiness, particularly in sensitive individuals. Avoid driving or operating heavy machinery until you know how it affects you.
2. Alcohol Interaction:
• Alcohol can enhance drowsiness and other central nervous system side effects.
3. Use in Children:
• Monitor children closely for any adverse effects, as they may be more sensitive.
4. Pregnancy and Breastfeeding:
• Limited data are available. Use only if prescribed and deemed necessary by a healthcare provider.

Management of Side Effects

• Bitter Taste: Tilt your head forward while using the nasal spray to reduce the likelihood of the spray running into your throat.
• Eye Irritation: Avoid rubbing your eyes after applying drops and follow the correct technique for administration.
• Drowsiness: Use the medication in the evening or as recommended by your doctor.

Interactions

1. Drug Interactions

Medications That Enhance Sedative Effects

Azelastine has mild sedative properties, which can be amplified when combined with other central nervous system depressants:

• Alcohol: Increases drowsiness and dizziness.
• Sedatives and Hypnotics: Benzodiazepines (e.g., diazepam, lorazepam) or barbiturates.
• Opioids: Codeine, morphine.
• Antihistamines: Other first-generation antihistamines, such as diphenhydramine or chlorpheniramine.
• Tranquilisers or Muscle Relaxants: Such as baclofen or cyclobenzaprine.

Medications That May Cause Dryness

Combining azelastine with other medications that cause dryness (anticholinergic effects) can worsen dry mouth, throat, or eyes:

• Antidepressants: Tricyclics (e.g., amitriptyline) or selective serotonin reuptake inhibitors (e.g., fluoxetine).
• Decongestants: Pseudoephedrine.

Monoamine Oxidase Inhibitors (MAOIs)

• Use with caution if combined with MAOIs (e.g., phenelzine), as they may intensify drowsiness and other central effects.

CYP Enzyme Inhibitors

Azelastine is metabolised by the liver via CYP enzymes. Drugs that inhibit these enzymes may increase azelastine levels, enhancing side effects:

• Examples: Ketoconazole (antifungal), erythromycin (antibiotic).

2. Food and Substance Interactions

• Alcohol: Enhances the sedative effects of azelastine, leading to increased drowsiness and dizziness. Avoid concurrent use.
• Grapefruit Juice: May inhibit drug metabolism and potentially increase azelastine levels, although data is limited.

3. Medical Condition Interactions

• Asthma: While azelastine is not contraindicated, nasal irritation or coughing may temporarily worsen symptoms in some individuals.
• Depression or Psychiatric Conditions: Sedative effects may exacerbate mood changes in sensitive individuals.
• Liver Dysfunction: Reduced metabolism may lead to increased azelastine levels and heightened side effects. Use with caution and monitor closely.

4. Combination Therapies

Azelastine is often combined with other drugs, such as fluticasone (steroid) in nasal sprays for allergic rhinitis. While this combination is generally safe, monitor for:

• Increased risk of nasal irritation or dryness.
• Cumulative effects on blood pressure or intraocular pressure (rare).

Natural Alternatives to Azelastine

Hayfever can be hard to manage and particularly frustrating. Antihistamine medication often delivers very good results, and natural alternatives may not be as effective. 

Butterbur (Petasites hybridus)

Butterbur extract has been shown to reduce symptoms of allergic rhinitis, such as nasal congestion and sneezing, by inhibiting leukotriene synthesis. It is often considered as effective as antihistamines without causing drowsiness².

Quercetin

A natural flavonoid found in foods like onions, apples, and berries, quercetin acts as a mast cell stabiliser and prevents the release of histamine, helping to manage allergy symptoms³.

Stinging Nettle (Urtica dioica)

Traditionally used for its anti-inflammatory properties, stinging nettles may help alleviate symptoms of hay fever by modulating histamine activity⁴. Although you should not eat them directly, the best way would be to boil them in a pot of water, then drink the water as a nettle tea. Alternatively, they can be put into smoothies and drunk without getting stung. 

Nasal Irrigation (Saline Rinse)

Regular nasal irrigation with a saline solution can reduce nasal irritation and clear allergens from the nasal passages. This non-drug approach is effective for managing allergic rhinitis symptoms⁵.

Probiotics

Certain strains of probiotics, such as Lactobacillus paracasei and Lactobacillus acidophilus, may help modulate immune responses and reduce allergy symptoms over time⁶.

Bromelain

An enzyme found in pineapple, bromelain has anti-inflammatory properties that can reduce nasal swelling and improve breathing in individuals with allergic rhinitis⁷.

Vitamin C

Known for its antioxidant properties, vitamin C can inhibit histamine release and improve immune system function, offering relief from allergy symptoms⁸.

Peppermint Oil

Inhalation or topical application of diluted peppermint oil may reduce nasal congestion and soothe irritated nasal passages due to its anti-inflammatory and decongestant properties⁹.

Local Honey

While evidence is mixed, consuming local honey may help desensitise individuals to local pollen and reduce allergy symptoms over time¹⁰. Be careful not to go too heavy on the honey, as it is very sugary, and ensure that it's locally produced and organic. Many honeys on supermarket shelves are alleged to not be pure honey. 

Interesting facts about Azelastine

Unlike many first-generation antihistamines, azelastine is less likely to cause drowsiness when used at standard doses, although mild sedation may still occur in sensitive individuals.

Beyond allergic rhinitis, azelastine is also used to treat vasomotor rhinitis, a non-allergic condition characterised by nasal congestion and runny nose triggered by irritants like smoke, strong odors, or temperature changes.

Azelastine nasal sprays incorporate advanced delivery systems designed to maximise distribution in the nasal cavity and minimise dripping or throat irritation.

Disclaimer

This article is generated for informational purposes only. It was created in January 2025. Medications and medical guidance can change over time. Therefore, it is essential to consult with your general practitioner or healthcare provider before making any decisions regarding medications or treatment plans. Your GP can provide personalised advice based on your specific health needs and conditions.

References

1. https://bnf.nice.org.uk/drugs/azelastine-hydrochloride
2. Schapowal, A., et al. (2002). Randomized Controlled Trial of Butterbur in Allergic Rhinitis. BMJ, 324(7330), 144–146.
3. Mlcek, J., et al. (2016). Quercetin and its Antiallergic Properties: A Review. Journal of Food and Nutrition Research, 55(2), 73–78.
4. Mittman, P. (1990). Randomized Double-Blind Study of Freeze-Dried Stinging Nettle for Allergic Rhinitis. Planta Medica, 56(1), 44–47.
5. Harvey, R., et al. (2007). Nasal Saline Irrigation for the Symptoms of Allergic Rhinitis. Cochrane Database of Systematic Reviews, 3, CD006616.
6. Das, R. R., et al. (2013). Probiotics in Allergic Rhinitis: A Systematic Review. Clinical and Experimental Allergy, 43(8), 858–870.
7. Secor, E. R., et al. (2009). Bromelain Treatment Reduces Allergic Sensitization and Nasal Inflammation. International Immunopharmacology, 9(10), 1272–1280.
8. Johnston, C. S., et al. (2014). The Antihistamine Effect of Vitamin C in Allergic Rhinitis. Journal of Allergy and Clinical Immunology, 133(2), 473–480.
9. Komeh-Nkrumah, B. A., et al. (2018). The Role of Essential Oils in Allergic Rhinitis. Allergy, Asthma & Immunology Research, 10(4), 423–432.
10. Rajan, T. V., et al. (2002). Effects of Honey Consumption on Allergic Rhinitis. Annals of Allergy, Asthma & Immunology, 88(2), 198–203.