Desloratadine (Aerius®)

Desloratadine is a third-generation antihistamine and the active metabolite of loratadine. It is used to treat allergic rhinitis (hay fever), allergic rhinoconjunctivitis, and chronic urticaria (hives).

The active ingredient selectively blocks H1 histamine receptors and thus acts specifically against typical allergy symptoms such as sneezing, runny nose, itching, and watery eyes. Desloratadine is available under the brand name Aerius® and as a generic from numerous manufacturers (e.g., Desloratadin-ratiopharm®, Desloratadin HEXAL®).

Unlike older antihistamines such as cetirizine or diphenhydramine, desloratadine barely crosses the blood-brain barrier and therefore usually does not cause drowsiness.

Desloratadine acts specifically on the allergic reaction:

Mechanism of action:

• Selective blockade of peripheral H1 histamine receptors
• Prevents histamine from exerting its allergic effects
• Additional anti-inflammatory properties (inhibits interleukin-4, interleukin-13, and other mediators)
• Inhibited the release of inflammatory substances from mast cells in laboratory studies (clinical relevance not yet confirmed)

Advantages over older antihistamines:

• No relevant sedation (does not make you sleepy)
• No impairment of driving ability at the recommended dose
• No interaction with grapefruit juice or CYP3A4 inhibitors

Onset of action: The effect begins within 1 hour. Maximum plasma concentration is reached after about 3 hours. The duration of action is 24 hours, so taking it once daily is sufficient.

Desloratadine is suitable for:

• Adults and adolescents aged 12 years and older with allergic rhinitis (hay fever)
• Patients with chronic idiopathic urticaria (hives)
• Year-round or seasonal allergy symptoms
• House dust allergy with a constantly runny nose

Especially recommended for:

• Patients who need to stay fully functional during the day (work, driving)
• When loratadine is not effective enough
• When a non-sedating antihistamine is needed
• Combination with nasal corticosteroids for severe symptoms

Not suitable for:

• Children under 1 year of age (as a solution from 1 year, tablets from 12 years)
• Hypersensitivity to desloratadine or loratadine

Adults and adolescents aged 12 years and older:

• 5 mg once daily (one film-coated tablet)
• Take with or without food

Children (as syrup/solution, prescribed by a doctor):

• 1–5 years: 1.25 mg once daily
• 6–11 years: 2.5 mg once daily

Available dosage forms:

• 5 mg film-coated tablets
• 5 mg orodispersible tablets (Aerius® orodispersible tablets)
• 0.5 mg/ml oral solution (for children)

Duration of use:

• Seasonal: during the pollen season
• Year-round: for perennial rhinitis or chronic urticaria, as recommended by a doctor

How to take:

• Once daily, always at the same time of day
• With or without food
• Swallow the film-coated tablet with water
• Place the orodispersible tablet on the tongue; it dissolves without water

Important information:

• Take regularly for optimal effect during the pollen season
• Can also be taken as needed (intermittently)
• In severe kidney impairment, use only with caution
• If you miss a dose: take the next dose at the usual time, do not take a double dose

Tips for hay fever:

• Additionally, a nasal corticosteroid for a stuffy nose
• Check the pollen calendar and reduce exposure
• Allergen avoidance measures support the treatment

Desloratadine must not be taken in cases of:

• Hypersensitivity to desloratadine or loratadine
• Hypersensitivity to any of the other ingredients

Caution in cases of:

• Severe kidney impairment
• History of epilepsy (the seizure threshold may be lowered)
• Concurrent use of medications that lower the seizure threshold

Pregnancy and breastfeeding: Use during pregnancy should only take place after a strict benefit-risk assessment. Desloratadine passes into breast milk. During breastfeeding, it should only be taken after consulting a doctor.

Common (1–10%):

• Headache
• Dry mouth
• Fatigue (much less common than with older antihistamines)

Very rare (< 0.01%):

• Dizziness
• Sleep disorders
• Gastrointestinal complaints
• Tachycardia (racing heart)
• Myalgia (muscle pain)
• Hypersensitivity reactions
• Elevated liver enzymes
• Anaphylaxis (extremely rare)

General: Desloratadine is considered very well tolerated. In clinical studies, the rate of side effects was barely higher than with placebo. The sedation rate is below 2% and is therefore significantly lower than with cetirizine.

Clinically relevant interactions: Desloratadine has a very favorable interaction profile. It is not significantly metabolized by CYP enzymes.

No relevant interaction with:

• Grapefruit juice
• Ketoconazole, erythromycin (no QT prolongation)
• Alcohol (no increase in sedation in studies, but caution is still advised)
• Food

Caution with:

• Other medications with a sedative effect (although desloratadine itself causes hardly any sedation)
• Medications that prolong the QT interval (theoretical risk)

Note: Desloratadine has one of the most favorable interaction profiles of all antihistamines.