Antihistamine (H1, second-generation, non-sedating) Pregnancy: A large amount of data on pregnant women (more than 1,000 pregnancy outcomes) indicate no malformative nor foeto/neonatal toxicity; as a precautionary measure it is preferable to avoid desloratadine during pregnancy. Identified in breastfed newborns/infants — decide whether to discontinue breast-feeding or desloratadine, weighing benefits of each.

Desloratadine

Brand names: Neoclarityn, Aerius

Desloratadine is a non-sedating second-generation H1 antihistamine, the active metabolite of loratadine, used for allergic rhinitis and chronic urticaria.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: One tablet once a day (SPC product = desloratadine 5 mg film-coated tablets; §4.8 refers to "the recommended dose of 5 mg daily")

Route: Oral use — the dose can be taken with or without food

Frequency: Once daily

Adults and adolescents 12 years of age and over: one tablet once a day. Intermittent allergic rhinitis (symptoms for less than 4 days per week or for less than 4 weeks) should be managed according to the patient's disease history — treatment could be discontinued after symptoms resolve and reinitiated on their reappearance. In persistent allergic rhinitis (symptoms for 4 days or more per week and for more than 4 weeks), continued treatment may be proposed during allergen exposure periods. Paediatric: there is limited clinical trial efficacy experience in adolescents 12 through 17 years of age; safety and efficacy of the film-coated tablets in children below 12 years have not been established — no per-kg dose is stated in the SPC. Administer with caution in patients with a medical or familial history of seizures, mainly young children (more susceptible to new seizures); consider discontinuing if a seizure occurs on treatment. Contains lactose — not for patients with rare hereditary galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption.

Dose adjustments

Renal

In the case of severe renal insufficiency, desloratadine should be used with caution (§4.4). No numerical dose adjustment is stated in the SPC.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance, to any of the excipients, or to loratadine

Side effects

Fatigue (common; 1.2% in excess of placebo)
Dry mouth (common; 0.8%)
Headache (common; 0.6% — most common event in adolescents 12–17 years)
Dizziness, somnolence, insomnia, psychomotor hyperactivity, tachycardia, palpitations (very rare)
Hypersensitivity reactions including anaphylaxis, angioedema, dyspnoea, pruritus, rash and urticaria; elevations of liver enzymes, increased bilirubin, hepatitis (very rare)
Paediatric post-marketing: QT prolongation, arrhythmia, bradycardia, abnormal behaviour, aggression; an observational study indicated increased incidence of new-onset seizure in patients 0–19 years

Interactions

No clinically relevant interactions observed in clinical trials with desloratadine tablets when erythromycin or ketoconazole were co-administered (§4.5)
Alcohol — desloratadine did not potentiate the performance-impairing effects of alcohol in a clinical pharmacology trial, but cases of alcohol intolerance and intoxication have been reported post-marketing; caution is recommended if alcohol is taken concomitantly
Interaction studies have only been performed in adults

Clinical monograph

How it works

It is a selective peripheral histamine H1 receptor antagonist that inhibits the effects of histamine released in allergic reactions.

Prescribing in practice

Although usually non-sedating, patients should be cautioned that drowsiness can occur and may affect driving or skilled tasks.
It can be taken once daily with or without food, which supports adherence.
Caution is advised in severe renal or hepatic impairment.

Monitoring

No routine monitoring is required; assess symptom control clinically.

Counselling the patient

Take once daily and report any drowsiness.
It can be taken with or without food.
Use regularly during the allergy season for best effect.

Evidence & guidelines

Second-generation antihistamines such as desloratadine are recommended first-line for allergic rhinitis and chronic urticaria in current guidance.

Reference: SmPC Neoclarityn / Aerius; BSACI Rhinitis Guideline 2017; EAACI/GA²LEN Urticaria Guideline 2022; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Drugs

Bilastine · Antihistamine (H1, second-generation, non-sedating)

Pathways