Allergic rhinitis
First line
First-line allergic rhinitis treatment per ARIA. Efficacy is confirmed in numerous RCTs. Advantage over cetirizine: minimal drowsiness, which matters for drivers and precision workers. Adult dose is 10 mg once daily.
Second-generation antihistamines
ATC code: R06AX13 (Loratadine)
Long-acting peripheral H1-receptor antagonist. Virtually no CNS penetration, resulting in minimal sedation. Hepatic metabolism via CYP3A4 and CYP2D6 produces the active metabolite desloratadine. Onset of action 1-3 hours, duration exceeding 24 hours.
First line
First-line allergic rhinitis treatment per ARIA. Efficacy is confirmed in numerous RCTs. Advantage over cetirizine: minimal drowsiness, which matters for drivers and precision workers. Adult dose is 10 mg once daily.
First line
First-line treatment for chronic urticaria. As with cetirizine, up-dosing to 4-fold is permitted per /GA2LEN guidelines if the standard dose is insufficient. Higher doses are well tolerated without significant increase in sedation.
The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.
Not recommended
Loratadine does not work for the common cold. The 2015 Cochrane review «Antihistamines for the common cold» showed second-generation H1 antagonists do not improve cold symptoms. Only first-generation H1 drugs show a weak effect through their anticholinergic action, which loratadine largely lacks. , , and CDC do not include antihistamines in common cold recommendations. Widespread use in post-Soviet countries is inconsistent with the evidence base.
Not recommended
Systemic loratadine is not used in viral or bacterial conjunctivitis. The Preferred Practice Pattern distinguishes allergic conjunctivitis, where H1 blockers work, from infectious, where histamine is not involved in pathogenesis. Viral cases are treated symptomatically (cold compresses, artificial tears), bacterial with topical antibiotics.
Not recommended
Loratadine is not used in non-allergic rhinitis (vasomotor, idiopathic, infectious URI-related, medication-induced). ARIA 2020 and separate allergic and non-allergic rhinitis: systemic H1 blockers are not useful in the latter because the pathogenesis is not histamine-mediated. Topical azelastine and corticosteroids work for vasomotor rhinitis.
Not recommended
Routine loratadine before planned vaccination in healthy people without allergy history is not supported by international societies. CDC Pink Book, ACIP 2023, and : antihistamine premedication does not prevent anaphylaxis because the anaphylactic cascade outpaces H1 blockade. Selected RCTs show reduced vaccine immunogenicity of 10–25 % with antihistamine and antipyretic premedication (Prymula R et al. Lancet 2009). Patients with confirmed drug or vaccine allergy are managed individually by an allergist.
4 pairs found. Sorted from critical to minor.
Mechanism
Loratadine causes minimal QT prolongation at standard doses, but with CYP3A4 blockade by amiodarone, loratadine levels rise, potentially amplifying cardiac effects in predisposed patients.
Symptoms
QT prolongation on ECG. Dizziness, syncope, palpitations. Rarely: polymorphic ventricular tachycardia (torsades de pointes). Risk is higher with hypokalaemia, hypomagnesaemia, bradycardia, and ischaemic heart disease.
Management
Standard loratadine 10 mg/day is kept. In patients with prior QT prolongation, hypokalaemia, or bradycardia below 60 bpm, switch to cetirizine (minimal QT effect). Check ECG every 3–6 months on the combination.
Mechanism
Loratadine rarely causes sedation at standard doses. With diazepam, mild additive CNS depression is possible, especially in older patients.
Symptoms
Sedation, fatigue, slowed reactions, impaired coordination. In older patients: fall and fracture risk. Driving and operating machinery: accident risk.
Management
On standard loratadine (10 mg/day) with intermittent diazepam (e.g. for anxiety), no adjustment needed. In older patients and on long-term benzodiazepine therapy, watch for sedation signs. For anxiety disorders, consider alternatives to diazepam: buspirone or CBT.
Mechanism
Loratadine is a second-generation antihistamine with minimal blood-brain barrier penetration. With opioids, mild additive CNS depression is possible, especially in older patients.
Symptoms
Sedation, fatigue, slowed reactions, impaired coordination. In older patients: fall and fracture risk. Driving and operating machinery: accident risk.
Management
No dose adjustment needed. In older patients and palliative care, watch for sedation signs. Loratadine is preferred over cetirizine or chlorpheniramine on concurrent opioid therapy — minimal sedation. With marked sedation, stop the antihistamine.
Mechanism
Paracetamol and loratadine are metabolised by different pathways. No direct pharmacokinetic interaction.
Symptoms
The combination usually causes no specific symptoms. Each drug's individual side effects remain.
Management
No dose adjustment needed. The combination is standard in symptomatic formulations for acute respiratory infections and allergy.
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FDA category B. Considered a preferred antihistamine in pregnancy alongside cetirizine. Large cohort studies have not identified an increased risk of congenital malformations.
Passes into breast milk in negligible amounts. Compatible with breastfeeding per LactMed.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
Loratadine is evaluated for the following indications with varying evidence strength: Allergic rhinitis (evidence tier A), Chronic urticaria (evidence tier A), Non-allergic rhinitis (evidence tier F). See the full indication matrix with dosing and citations above on this page.
Common side effects of Loratadine (≥ 1 in 100): Headache, Dry mouth, Fatigue (rare). See the Safety section for uncommon and serious reactions.
FDA category B. FDA category B. Considered a preferred antihistamine in pregnancy alongside cetirizine. Large cohort studies have not identified an increased risk of congenital malformations.
Passes into breast milk in negligible amounts. Compatible with breastfeeding per LactMed.
Loratadine is contraindicated in: Hypersensitivity to loratadine or desloratadine. Full list in the Safety section.
second-generation H1 blockers do not work in URI. The 2015 Cochrane review confirmed the null effect on 5,099 participants. Short-course nasal decongestants and saline rinses help cold symptoms.
ARIA clearly separates allergic and non-allergic rhinitis. In vasomotor, idiopathic, infectious, and medication-induced rhinitis, systemic H1 blockers do not work – histamine is not the key mediator in pathogenesis.
CDC, ACIP, and WHO do not support this practice. Antihistamines do not prevent anaphylaxis. In selected RCTs, antihistamine and antipyretic premedication reduced vaccine immunogenicity by 10–25 %.
in viral or bacterial conjunctivitis, systemic antihistamines do not work. AAO recommends symptomatic treatment for viral and topical antibiotics for bacterial cases.