Lortadine

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Medically reviewed

Laura Arias

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Lortadine

Property Description
Active Ingredient Loratadine
Form Tablet, Oral Solution, Syrup
Pharmacological Class Second-Generation H1-Antihistamine
General Purpose Relief of Allergic Symptoms
Origin Synthetic (Piperidine derivative)

Lortadine is a medication whose active ingredient is Loratadine, which is chemically defined as a synthetic tricyclic piperidine derivative. This compound is fundamentally classified as a second-generation H1-antihistamine, a pharmacological category designed to counteract the effects of histamine released during allergic episodes.


Classification and Core Action

This medication is recognized as a non-sedating agent, a distinction supported by pharmacological studies. It achieves this profile by operating primarily as a peripheral H1-receptor antagonist, which means its mechanism of action targets receptors located outside the central nervous system. This focused action prevents histamine from binding to these peripheral receptors, which is the root cause of many physical allergy symptoms.


Composition and Available Forms

The therapeutic benefit of Lortadine comes solely from Loratadine, establishing it as a single-ingredient product intended for the oral route of administration. Loratadine is supplied in several common dosage forms to accommodate patient needs, including the conventional tablet, a liquid oral solution or syrup, and an orally disintegrating tablet (ODT). These different preparations contain the same active substance. The availability of forms such as the oral solution facilitates use in both adults and pediatric patients, ensuring proper systemic delivery of the active compound.

Regulatory References

  1. NIH/MedlinePlus Loratadine Drug Information

What side effects are possible with Lortadine?

Adverse Reactions and Safety Profile

Loratadine's safety profile is generally characterized by common, mild side effects, with a low incidence of serious adverse events.

Common and Less Common Reactions

The most frequently reported adverse reactions, categorized as Common (ge 1% to <10%) in clinical trials, include headache, somnolence (drowsiness/sedation), fatigue, and dry mouth. Nervousness and increased appetite are classified among the less common reactions.

Serious and Clinically Significant Adverse Reactions

Regulatory documents highlight hypersensitivity reactions as serious, very rare (<0.01%) adverse reactions. These include anaphylaxis and angioedema (swelling of the face, tongue, or throat). Other very rare, serious events documented in post-marketing surveillance are convulsion/fit, tachycardia (rapid heartbeat), palpitations, and abnormal hepatic function.

Safety Restrictions and Precautions

Contraindications include known hypersensitivity to loratadine or its components. The drug should be discontinued for approximately 48 hours before allergy skin testing, as antihistamines can suppress positive test reactions.

Caution is required in specific populations: patients with severe liver or kidney impairment may require a lower dose to avoid increased exposure and potential adverse effects, particularly somnolence. Due to the potential for drowsiness or reduced alertness, caution is advised when operating machinery or driving until the individual's response to the medication is known.

Overdose and Emergency Response

Overdose and When to Seek Help

Official regulatory information describes specific manifestations and required actions in cases of Loratadine overdosage.

Overdose is documented to present with signs that include somnolence (drowsiness), tachycardia (rapid heartbeat), and headache, alongside the potential for increased occurrence of anticholinergic symptoms.


Mandated Emergency Actions

Upon suspicion of overdosage, official labeling mandates that individuals seek immediate medical attention or contact a Poison Control Center right away.

Management is focused on symptomatic and supportive care. Procedures that may be initiated include the administration of activated charcoal as a slurry with water, and gastric lavage may be considered. General symptomatic and supportive measures must be instituted and maintained for as long as necessary.


Regulatory Notes on Treatment and Monitoring

Domain Statement
Antidote Status No specific antidote is officially documented.
Monitoring Medical monitoring of the patient is required to be continued after emergency treatment.
Dialysis Loratadine is not removed by haemodialysis, and removal by peritoneal dialysis is not known.

Certain patient groups, including the elderly and those with hepatic or renal impairment, may be at increased risk for somnolence if the recommended dose is exceeded.

Therapeutic Uses of Lortadine

Main Uses and Benefits of Loratadine

Loratadine is a second-generation antihistamine used primarily to manage symptoms associated with upper respiratory allergies and certain skin conditions. Unlike earlier antihistamines, it is designed to be long-acting and is generally associated with a lower incidence of drowsiness.

Relief of Allergic Rhinitis

Loratadine is frequently used to treat the symptoms of allergic rhinitis, which includes both seasonal allergies (such as hay fever) and perennial allergies (caused by year-round triggers like dust mites or pet dander). It helps alleviate a variety of symptoms caused by the body's immune response to allergens, including:

  • Sneezing: Reducing the frequency and severity of sneezing fits.
  • Rhinorrhea: Managing a runny nose by decreasing mucus production.
  • Nasal Congestion: Helping to relieve the feeling of a blocked or stuffy nose.
  • Itching: Addressing itchiness in the nose or throat.
  • Ocular Symptoms: Reducing redness, itching, and watery discharge from the eyes.

Management of Chronic Urticaria

In addition to respiratory symptoms, loratadine is utilized in the treatment of chronic idiopathic urticaria, also known as chronic hives. In this context, the medication helps to:

  • Reduce Wheals: Decrease the number and size of raised, red itchy bumps on the skin.
  • Alleviate Itching: Provide relief from the persistent skin irritation and pruritus associated with hives.

Mechanism and Benefits

The primary benefit of loratadine is its ability to block the action of histamine, a natural substance in the body that triggers allergic reactions. Because it does not readily cross the blood-brain barrier, it provides relief from allergy symptoms for up to 24 hours with a reduced likelihood of affecting central nervous system functions, such as alertness or coordination, compared to first-generation alternatives.

Regulatory References

  1. NIH MedlinePlus overview

Eligibility and Restrictions for Use

Who Can and Cannot Use Loratadine

The eligibility profile for using Loratadine is determined by regulatory agencies based on age, physiological status, and contraindications. The medicine is primarily authorized for use in adults and adolescents 12 years of age and older, and in children between 2 and 11 years of age.


Absolute Exclusions and Restrictions

Classification Population or Condition
Contraindicated Individuals with a known hypersensitivity (allergy) to loratadine or any excipients.
Contraindicated Breastfeeding women, as the substance is excreted into human milk.
Not Recommended Children under 2 years of age, as safety and efficacy are not established in this group.
Not Recommended Pregnant women, generally advised as a precautionary measure.

Conditional Use Requirements

Regulatory documents advise that use must be conditional for patients with severe hepatic impairment (severe liver disease), which may necessitate an adjustment to the dose frequency. Caution is also advised in cases of severe renal impairment. Furthermore, the medicine must be discontinued for at least 48 hours prior to allergy skin testing to prevent interference with results.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The official interaction profile for Loratadine is determined by its metabolic pathway and specific procedural constraints, as documented in regulatory sources.

Interaction Type Regulatory Finding
Pharmacokinetic Metabolism involves Cytochrome P450 enzymes ( CYP3 A4 and CYP2 D6). Co-administration with inhibitors of these enzymes may increase Loratadine plasma concentrations due to reduced clearance.
Pharmacodynamic Formal studies document no potentiating effects on psychomotor performance when taken with alcohol. Potential for additive anticholinergic symptoms with other agents having this property exists.

Official Interaction Statements

  • Co-administration with substances such as Ketoconazole, Erythromycin, and Cimetidine substantially increases the systemic exposure of Loratadine, a result of reduced metabolic clearance.
  • Administration must be discontinued for a minimum of 48 hours prior to conducting skin tests for allergies to prevent a procedural interaction that interferes with the diagnostic results.
  • Ingestion of food increases the overall systemic bioavailability of the drug while simultaneously delaying the time it takes to reach peak plasma concentration.
  • Systemic exposure is documented to be increased in patients with severe hepatic impairment and chronic renal impairment, a condition noted in regulatory labeling.

Connection to the overall interaction profile The official documents primarily establish a pharmacokinetic profile vulnerable to CYP3 A4 and CYP2 D6 inhibition, which formally alters drug exposure, alongside a mandatory procedural constraint related to allergy testing.

Mechanism of Action

The mechanism of Loratadine is defined by its action as a selective inverse agonist at peripheral Histamine boldsymbolH1 receptors. The molecule binds to the receptor, stabilizing it in an inactive conformation. This molecular interaction restricts the H1 receptor's availability for the endogenous mediator, histamine, thereby suppressing the initiation of histamine-driven cellular signaling. This action directly affects vascular tissue by interrupting the signal cascade that normally increases capillary permeability and vasodilation in the microvasculature. By modifying these early molecular steps, the drug restricts the functional consequences of elevated mediator activity on vascular tissue, reducing the potential for fluid extravasation across the vessel wall. Furthermore, Loratadine exhibits limited blood-brain barrier penetration due to its physicochemical properties. Consequently, its mechanistic activity is primarily restricted to peripheral H1 receptors, avoiding significant engagement of central H1 pathways.

Dosage and Administration Information

Loratadine is an antihistamine used to temporarily relieve symptoms caused by hay fever or other upper respiratory allergies, such as sneezing, runny nose, and itching of the eyes, nose, or throat.

Take this medication exactly as directed on the label or by your healthcare provider. Do not take more of it, take it more often, or take it for a longer period than instructed, as taking more than directed may cause drowsiness.

Administration

Loratadine is available in several oral dosage forms, including tablets, capsules, orally disintegrating tablets (ODT), chewable tablets, and liquid/syrup. All forms can be taken once daily with or without food.

  • Tablets/Capsules: Swallow the tablet or capsule whole with a drink of water. Do not cut, chew, or crush extended-release forms.
  • Orally Disintegrating Tablets (ODT): Follow the package directions to remove the tablet and immediately place it on your tongue. The tablet will dissolve quickly and can be swallowed with or without water. Do not push the tablet through the foil packaging.
  • Liquid/Syrup: Use the dosing syringe, spoon, or cup provided with the medication to measure the dose accurately. Do not use a household teaspoon to measure liquid medicine.
  • Chewable Tablets: Chew or crush the tablet completely before swallowing.

General Dosage Guidance

Patient Group Recommended Dosage Maximum Daily Dose
Adults and Children 6 years and older 10 mg once daily 10 mg
Children 2 to under 6 years of age 5 mg once daily 5 mg

Consumers with kidney or liver disease should consult a healthcare professional before use, as a different dosage may be necessary.

Missed Dose

If you miss a dose, take it as soon as you remember. If it is almost time for your next scheduled dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to compensate for a missed one.

Recent Clinical Evidence

Research Evidence / Overview of Studies

Clinical Trials and Research Findings

Studies have investigated the primary endpoints of various conditions, most notably allergic rhinitis (hay fever) and chronic idiopathic urticaria (hives). Research has examined the measurement of symptoms recorded in participants over observation periods, which often included assessments of sneezing, nasal discharge, and itching. Research has also investigated outcomes related to quality of life in participants over treatment courses.

  • Study 1 (Phase III RCT): A randomized, controlled trial enrolled adult participants to compare the drug against a placebo for the management of allergic symptoms. Studies explored the recorded measurements of reported pain and fatigue, sometimes in combination with other therapeutic agents.

  • Study 2 (Observational): A separate study involving older adult participants tracked subject discontinuation rates over a six-month period, providing data on the long-term use of the medication.


Symptom Measurements and Other Investigated Uses

Studies investigated the rate of change in temperature recorded in pediatric participants in the context of acute infections. Furthermore, researchers recorded the average duration of symptoms in participants, including those who received the drug, in studies focused on acute infections and the common cold.

Research has also investigated the use of Loratadine for bone pain associated with granulocyte-colony stimulating factor (G-CSF) therapy in specific oncology settings. This research focused on the drug's properties as an H1-antihistamine to modulate pain pathways thought to involve histamine release.


Research Context

Research has also investigated the drug in combination with other agents, such as intranasal corticosteroids, for allergic rhinitis. This section describes what was studied in research environments. Clinical decisions require consultation with a healthcare provider.

Frequently Asked Questions (FAQ)

Common questions about Lortadine (FAQ)

Q: How quickly does Lortadine usually start working?

Studies and official information indicate that the antihistaminic effects of Lortadine generally begin within 1 to 3 hours after a dose is taken. The onset of action is consistent across various official product documents.


Q: What is the expected duration of effect for a dose of Lortadine?

Official studies examining Lortadine's pharmacodynamics indicate the antihistaminic effect of a single dose lasts in excess of 24 hours. This duration of action is consistent with its authorized once-daily dosing.


Q: Can Lortadine be used for things other than allergies?

The official indication for Lortadine is primarily for the temporary relief of symptoms caused by hay fever or other upper respiratory allergies. It is also officially indicated for chronic idiopathic urticaria (commonly known as chronic hives).


Q: Is Lortadine a type of steroid or cortisone?

Lortadine is not a steroid or cortisone. According to regulatory documents, it is chemically classified as a second-generation H1-antihistamine, which belongs to a different pharmacological class.


Q: Can Lortadine be used to help with sinus pressure?

Official documents describe the drug’s purpose as providing relief for symptoms such as sneezing, runny nose, and itching of the eyes, nose, or throat due to allergies.


Q: Do studies suggest Lortadine is better taken in the morning or at night?

Lortadine is directed in official documents to be taken once daily. It may be taken either in the morning or at night, and with or without food, as guided by the prescribing information.


Q: How is the interaction between Lortadine and grapefruit juice described?

Official product information states that the ingestion of food, in general, increases the overall systemic bioavailability of the drug while simultaneously delaying the time it takes to reach peak plasma concentration. This descriptive profile applies broadly to food taken orally.


Q: Does Lortadine cause weight gain as a side effect?

Increased appetite is reported as a less common adverse reaction in clinical trials, according to official documents. While increased appetite is documented, the official information does not universally confirm weight gain as a common or guaranteed effect.


Q: Is there any research on Lortadine's potential impact on cognitive function?

Yes. Official reviews have examined the effects of Lortadine on cognitive and psychomotor functioning. Findings from these studies generally indicate that the effects are comparable to placebo, consistent with its classification as a non-sedating antihistamine.


Q: Is it normal to feel a bit restless after taking Lortadine?

Nervousness is listed in official safety documents as a less common adverse reaction reported in clinical trials. Restlessness, when experienced, is often associated with this documented nervous system effect.


Q: What does the research say about Lortadine's effect on driving ability?

Studies have investigated the drug's effect on actual driving performance, with results generally comparable to placebo. However, due to the potential for drowsiness, official documents advise caution when operating machinery or driving.


Q: Why are people told to stop taking Lortadine before an allergy skin test?

Official instructions advise discontinuing the drug for a minimum of 48 hours prior to an allergy skin test. This is a procedural requirement intended to prevent the antihistamine from interfering with the diagnostic results, as it can suppress or block positive skin test reactions.


Q: Has Lortadine been studied in people with kidney problems?

Yes. Pharmacokinetic studies have been conducted on subjects diagnosed with chronic renal impairment (long-term kidney problems). The data gathered from this research is used to determine recommendations for use in this population.


Q: What is the significance of the research evidence about Lortadine's long-term safety?

Research has included observational studies that tracked subject discontinuation rates over periods such as six months. This kind of research provides descriptive data on how the medication is tolerated during extended use.


Q: Can Lortadine affect the results of other medical tests?

The most explicit cautionary statement in official documents relates to the allergy skin test, where the drug must be discontinued to prevent interference with results. If other medical tests are scheduled, regulatory principles suggest informing the relevant healthcare professional about any medication use.


Q: Are there specific warning labels required for Lortadine in official sources?

Official product labeling includes specific warnings, such as advice to stop use and seek medical help if an allergic reaction occurs. Warnings also address the potential for drowsiness if more than the recommended amount is taken.


Q: Can Lortadine still be effective if I take it every day?

Yes. The drug is authorized for once-daily use, and official pharmacokinetic documentation indicates that its properties are generally not significantly altered by the duration of treatment. The documentation supports the drug's administration for chronic conditions.

How should Lortadine be stored and disposed of?

Storage Conditions

Loratadine must be stored at controlled room temperature, specifically between 20 C and 25 C (68 F and 77 F), with permitted short excursions up to 30 C (86 F). The product must be protected from excessive moisture and kept away from light. Storing the medication in a bathroom is prohibited, and the product must be kept from freezing.

Packaging and Handling

To ensure stability, the medication must remain in its original container and be kept tightly closed. Orally disintegrating tablets must be used immediately upon opening the individual blister pack. All forms of Loratadine must be stored out of the sight and reach of children.

Disposal Instructions

Unused or expired Loratadine must be discarded according to local regulations. Regulatory bodies advise using drug take-back programs or authorized collection sites as the preferred method of disposal. The product should not be flushed down the toilet or poured into a drain.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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