Products
Azelastine is available as a nasal spray and in eye drop form (eg, Allergodil, Dymista + fluticasone, generics). It has been approved in many countries since 1994.
Structure and properties
Azelastine (C22H24ClN3O, Mr = 381.9 g/mol) is present in drugs as azelastine hydrochloride, a white to almost white crystalline powder. It is a phthalazinone derivative and is almost odorless. Azelastine has a bitter taste, which can lead to taste disturbances and rarely even to discontinuation of therapy (see under adverse effects). A formulation containing sweeteners has therefore been developed to mask the taste.
Effects
Azelastine (ATC R01AC03, ATC R06AX19, ATC S01GX07) has antiallergic, antihistamine, and anti-inflammatory properties and inhibits the formation and release of inflammatory mediators such as leukotrienes. It has a high affinity for the H1 receptor, binds less strongly to the H2 receptor and relieves the symptoms of allergic rhinitis such as itching, sneezing, nasal congestion, and ocular symptomatology. The effect is rapid, with nasal application within approximately 15 to 30 minutes, and lasts up to 12 hours. Efficacy has been documented in clinical trials. Azelastine is not cardiotoxic.
Indications
Azelastine is approved in the form of a nasal spray for the treatment of hay fever and allergic rhinitis and as eye drops for the treatment of allergic conjunctivitis. In other countries, for example in the USA, but not in many countries, it is also commercially available for non-allergic vasomotor rhinitis and is effective according to the literature. Another potential use is for gustatory rhinitis (runny nose during eating).
Dosage
According to the prescribing information. The nasal spray or eye drops are used 1 to 2 times daily. To avoid a bitter taste in the mouth, the head may be tilted slightly forward when using the nasal spray and the spray may not be inhaled deeply.
Contraindications
Azelastine is contraindicated in hypersensitivity and should not be used as a nasal spray in children younger than 12 years (insufficient data) and as eye drops in children younger than 4 years. When driving a vehicle or operating heavy machinery, fatigue may occur as an adverse effect in individual cases, so caution is advised. When using the eye drops, simultaneous wearing of soft contact lenses is not recommended, as the preservative benzalkonium chloride may become embedded in the lenses. For complete precautions, see the drug label.
Interactions
No interactions have been reported with topical use. Azelastine is metabolized by CYPs. In rare cases, central side effects could be increased with depressant agents and alcohol.
Adverse effects
Possible adverse effects include taste disturbance, bad bitter taste due to the intrinsic taste of the substance, nausea, local discomfort of the eyes or nose, hypersensitivity, allergic reactions, skin rash, itching, hives, dizziness, headache, rarely fatigue, feeling weak, and tiredness.