Loratadine: Uses, Dosage & Side Effects
Non-drowsy second-generation antihistamine for allergic rhinitis, hay fever and chronic urticaria
Loratadine is one of the most widely used second-generation antihistamines worldwide, providing effective 24-hour relief from allergic symptoms with a very low risk of drowsiness. Available over the counter in most countries as both tablets and syrup, loratadine is used by adults and children to treat seasonal and perennial allergic rhinitis (hay fever), allergic conjunctivitis, and chronic idiopathic urticaria (hives). This comprehensive guide covers its mechanism of action, proper dosing, potential side effects, drug interactions, and important safety information based on international guidelines from the WHO, EMA, and FDA.
Quick Facts: Loratadine
Key Takeaways
- Loratadine is a second-generation, non-drowsy antihistamine that effectively relieves symptoms of allergic rhinitis (sneezing, runny nose, itchy eyes) and chronic hives, with effects lasting a full 24 hours from a single dose.
- The standard adult dose is 10 mg once daily (one tablet or 10 ml of syrup); children weighing 30 kg or less take 5 mg (5 ml syrup) once daily. Dose reduction is needed for severe liver impairment.
- Clinical studies show loratadine does not significantly impair driving ability or potentiate the effects of alcohol at recommended doses, making it one of the least sedating antihistamines available.
- Loratadine is extensively metabolised in the liver via CYP3A4 and CYP2D6 to its active metabolite desloratadine; drugs that inhibit these enzymes may increase loratadine levels, though clinical studies have not shown increased side effects.
- Loratadine should be avoided during pregnancy and breastfeeding unless recommended by a healthcare provider, and patients with severe liver disease should use a reduced dose.
What Is Loratadine and What Is It Used For?
Loratadine belongs to the class of second-generation antihistamines, also referred to as non-sedating antihistamines. First introduced in the late 1980s, it was one of the earliest non-drowsy alternatives to older antihistamines like diphenhydramine and chlorphenamine. Loratadine rapidly became one of the most widely used allergy medications globally and remains among the most recommended over-the-counter options for allergy symptom relief. It is included on the WHO Model List of Essential Medicines, reflecting its established safety profile and clinical importance in healthcare systems worldwide.
Loratadine is indicated for the relief of symptoms associated with allergic rhinitis, both seasonal and perennial. Seasonal allergic rhinitis, commonly known as hay fever, is triggered by outdoor allergens such as tree, grass, and weed pollens that are released during specific times of the year. Perennial allergic rhinitis, on the other hand, is caused by year-round exposure to indoor allergens such as house dust mites, pet dander, cockroach allergens, and mould spores. Symptoms treated by loratadine include sneezing, runny nose (rhinorrhoea), nasal congestion, itchy nose and throat, and red, watery, itchy eyes (allergic conjunctivitis).
In addition to allergic rhinitis, loratadine is widely used for the treatment of chronic idiopathic urticaria (CIU), also known as chronic spontaneous urticaria (CSU). This condition is characterised by recurrent episodes of hives — itchy, raised wheals on the skin — that persist for six weeks or longer without an identifiable external cause. The European Academy of Allergy and Clinical Immunology (EAACI), the Global Allergy and Asthma European Network (GA2LEN), the European Dermatology Forum (EDF), and the World Allergy Organization (WAO) jointly recommend second-generation H1-antihistamines, including loratadine, as first-line pharmacological treatment for chronic urticaria.
Loratadine is available as conventional tablets (10 mg) and as an oral syrup (1 mg/ml), making it suitable for both adults and children. In many countries, it is also available as orodispersible (rapidly disintegrating) tablets and in combination products with pseudoephedrine for additional relief of nasal congestion. The syrup formulation is particularly useful for children aged 2 years and older who cannot swallow tablets, though the tablet formulation is generally recommended for children from 6 years of age.
How Loratadine Works
Loratadine exerts its therapeutic effect through selective and potent antagonism of peripheral histamine H1 receptors. When the body encounters an allergen to which it has been sensitised, immune cells — primarily mast cells and basophils — undergo degranulation and release histamine along with other inflammatory mediators. Histamine then binds to H1 receptors present on blood vessels, smooth muscle, sensory nerve endings, and various other tissues, triggering the classical symptoms of an allergic reaction: vasodilation (leading to nasal congestion and skin flushing), increased vascular permeability (causing tissue swelling and rhinorrhoea), smooth muscle contraction (in the airways), mucus secretion, and stimulation of itch-sensing nerve fibres.
By competitively blocking H1 receptors, loratadine prevents histamine from initiating this cascade of events, effectively reducing or eliminating the allergic symptoms. A key advantage of loratadine over first-generation antihistamines is its limited ability to cross the blood-brain barrier. This selectivity for peripheral H1 receptors, rather than central nervous system receptors, is what accounts for its non-sedating profile at recommended doses. Positron emission tomography (PET) studies have confirmed that loratadine at 10 mg occupies less than 30% of brain H1 receptors, well below the 50% threshold associated with subjective drowsiness.
Beyond its direct H1 receptor antagonism, loratadine has been demonstrated to possess additional anti-allergic properties. It inhibits the release of histamine and leukotrienes from mast cells, reduces eosinophil chemotaxis (the directed migration of eosinophils to sites of allergic inflammation), and decreases the expression of intercellular adhesion molecule-1 (ICAM-1) on epithelial cells. These anti-inflammatory effects contribute to the reduction of both the early-phase allergic response (occurring within minutes of allergen exposure) and the late-phase response (occurring 4–24 hours later), providing comprehensive allergic symptom control throughout the dosing interval.
Pharmacokinetics
Loratadine is rapidly absorbed after oral administration, with peak plasma concentrations reached within 1 to 1.5 hours. It can be taken with or without food, as food does not significantly affect its overall bioavailability, though it may slightly delay the time to peak plasma concentration. Once absorbed, loratadine undergoes extensive first-pass metabolism in the liver, primarily via cytochrome P450 enzymes CYP3A4 and, to a lesser extent, CYP2D6. The major active metabolite produced is desloratadine (also known as 3-hydroxydesloratadine after further metabolism), which itself is a potent H1 receptor antagonist and is available as a separate pharmaceutical product.
The elimination half-life of loratadine is approximately 8.4 hours, while desloratadine has a significantly longer half-life of approximately 28 hours. This prolonged activity of the active metabolite is a key reason why loratadine provides effective symptom relief for a full 24-hour period, allowing convenient once-daily dosing. Approximately 40% of the administered dose is excreted in the urine and 42% in the faeces over a 10-day period, as both the parent compound and its metabolites. Notably, loratadine does not require dose adjustment in patients with kidney impairment, but patients with severe hepatic impairment should use a reduced dose owing to the drug's dependence on liver metabolism.
What Should You Know Before Taking Loratadine?
Contraindications
Loratadine is contraindicated in individuals with a known hypersensitivity to loratadine or to any of the excipients in the specific formulation being used. Cross-reactivity with desloratadine (the active metabolite of loratadine, marketed separately) is possible, so patients who have experienced an allergic reaction to desloratadine-containing products should also avoid loratadine. Hypersensitivity reactions, while extremely rare, can manifest as skin rash, urticaria (paradoxically), angioedema, or in very rare cases, anaphylaxis.
Unlike cetirizine, loratadine does not have a specific contraindication related to severe renal impairment, since it is primarily metabolised in the liver rather than excreted unchanged by the kidneys. However, patients with severe liver disease represent a distinct population of concern, as impaired hepatic metabolism can lead to significantly elevated plasma levels of loratadine and its metabolites, increasing the risk of adverse effects.
Warnings and Precautions
Patients with severe hepatic impairment (Child-Pugh C) should use loratadine with caution and at a reduced dose. The recommended approach is to initiate treatment at 10 mg every other day (or 5 mg daily where such strength is available), as the area under the concentration-time curve (AUC) for loratadine is approximately doubled in patients with chronic liver disease. In moderate hepatic impairment, standard dosing may be appropriate, but clinical monitoring is advisable, and patients should consult their healthcare provider.
If you are scheduled to undergo allergy testing, particularly skin prick tests (SPT) or intradermal tests, you must inform your doctor or allergist that you are taking loratadine. Antihistamines suppress the histamine-mediated wheal-and-flare response that these tests rely on to identify allergen sensitivities. Loratadine should be discontinued at least 48 hours (2 days) before allergy testing, though some allergists may recommend a longer washout period of up to 7 days, depending on the specific tests planned and the individual patient's response.
The syrup formulation of loratadine contains various excipients that may be relevant for certain patients. These include sugars (such as maltitol and sorbitol) and sweeteners that may not be suitable for individuals with hereditary fructose intolerance or rare sugar malabsorption disorders. Patients with these conditions should consult a healthcare provider or pharmacist before using the syrup formulation and may be better served by the tablet form. The syrup may also contain propylene glycol and sodium benzoate; while the amounts are generally small, patients with sensitivities to these excipients should be aware of their presence.
Loratadine is not recommended for children under 2 years of age. For children aged 2 to 6 years, the syrup formulation should be used as it allows for accurate weight-based dosing. Children weighing 30 kg or less should take 5 ml (5 mg) once daily. Always use the measuring device provided with the product — household teaspoons are not accurate enough for medication dosing.
Pregnancy and Breastfeeding
Loratadine should not be taken during pregnancy unless specifically recommended by a healthcare provider after careful assessment of the benefits and risks. While animal reproductive studies have not demonstrated teratogenic effects at doses many times higher than the human therapeutic dose, there are limited well-controlled studies in pregnant women. Available observational data from pregnancy registries and epidemiological studies have not identified a clear association between loratadine use in pregnancy and an increased risk of major birth defects, spontaneous abortion, or adverse maternal or fetal outcomes. Nevertheless, as a precautionary measure, it is recommended to avoid loratadine during pregnancy, particularly during the first trimester.
Loratadine and its active metabolite desloratadine are excreted in human breast milk, achieving concentrations that are approximately equivalent to plasma levels. Given this excretion profile, breastfeeding mothers should not use loratadine without first consulting a healthcare provider. If antihistamine therapy is essential during lactation, the prescriber will weigh the benefits of breastfeeding and the need for allergy treatment to determine the most appropriate course of action. Some clinical guidelines suggest that loratadine, given its well-established safety profile and minimal sedative properties, may be among the preferred antihistamines if treatment is necessary during breastfeeding, but this determination should be made by a qualified healthcare professional on a case-by-case basis.
Driving and Operating Machinery
In controlled clinical studies examining psychomotor performance and driving ability, loratadine at the recommended dose of 10 mg did not cause clinically significant sedation or impair the ability to perform tasks requiring alertness. This is a key distinction from first-generation antihistamines (such as diphenhydramine and chlorphenamine), which cross the blood-brain barrier readily and cause substantial drowsiness and psychomotor impairment. At the standard recommended dose, loratadine is not expected to make you drowsy or less alert, and most patients can continue driving and operating machinery as normal.
However, it is important to acknowledge that individual responses to any medication can vary. Drowsiness, although uncommon, has been reported as a side effect by some loratadine users, particularly during the first few days of treatment. You are personally responsible for assessing whether you are fit to drive or perform tasks requiring concentration after taking loratadine. If you experience any degree of drowsiness, you should refrain from driving or operating machinery until you feel fully alert. Concurrent use of alcohol or other central nervous system depressants, while not shown to be significantly potentiated by loratadine in clinical studies, may theoretically increase the risk of drowsiness in susceptible individuals.
How Does Loratadine Interact with Other Drugs?
One of the important pharmacological characteristics of loratadine, distinguishing it from cetirizine, is its extensive hepatic metabolism via the cytochrome P450 enzyme system, primarily through CYP3A4 and to a lesser extent CYP2D6. This metabolic pathway means that loratadine is susceptible to pharmacokinetic interactions with drugs that inhibit or induce these enzymes. However, an important clinical reassurance comes from the fact that in controlled studies, even when loratadine plasma concentrations were significantly increased by enzyme inhibitors, no clinically meaningful changes in adverse effect profile, QTc interval, or other safety parameters were observed.
The lack of clinically significant consequences from elevated loratadine levels is partly attributable to the drug's wide therapeutic index and the fact that its principal metabolite, desloratadine, is itself pharmacologically active. Thus, even when the parent compound accumulates due to enzyme inhibition, the overall pharmacological effect remains within safe and therapeutic bounds. Despite this reassuring data, it is nonetheless important to inform your doctor or pharmacist about all medications you are taking, including prescription medicines, over-the-counter products, and herbal or dietary supplements.
Loratadine has not been shown to potentiate the effects of alcohol in clinical studies. Unlike first-generation antihistamines, which markedly enhance alcohol-induced sedation and psychomotor impairment, loratadine at the recommended dose of 10 mg did not demonstrate additive effects with alcohol on performance measures. Nevertheless, as a general precaution, moderate alcohol consumption is advisable while taking any medication.
| Interacting Substance | Type | Effect | Clinical Advice |
|---|---|---|---|
| Ketoconazole | CYP3A4 inhibitor | Increases loratadine AUC by approximately 300%. No increase in adverse effects or QTc changes observed. | No dose adjustment required per labelling, but monitor for increased side effects. Consider alternative antifungal if available. |
| Erythromycin | CYP3A4 inhibitor | Increases loratadine plasma levels by approximately 40%. No ECG changes or increase in adverse events observed. | Generally safe to use concurrently. Monitor for drowsiness or other unusual effects. |
| Cimetidine | Non-selective CYP inhibitor | Increases loratadine AUC by approximately 100%. No clinical signs of increased toxicity observed. | Monitor for increased side effects. Consider alternative H2 antagonist (e.g. ranitidine or famotidine) if concerned. |
| Fluoxetine | CYP2D6 inhibitor | May moderately increase loratadine levels through inhibition of CYP2D6-mediated metabolism. | Clinical significance is generally low. Monitor for increased drowsiness. |
| Rifampicin | CYP3A4 inducer | May decrease loratadine plasma levels through enzyme induction, potentially reducing efficacy. | Monitor for reduced allergy symptom control. Dose increase may be needed under medical supervision. |
| Alcohol | Pharmacodynamic | Clinical studies showed no significant potentiation of alcohol effects at 10 mg dose. | Moderate consumption generally acceptable. Exercise caution with heavy alcohol use. |
| Other CNS depressants | Pharmacodynamic | Theoretical additive sedation, though loratadine has minimal CNS activity at recommended doses. | Monitor for increased drowsiness when combined with benzodiazepines, opioids, or other sedating medications. |
Important Considerations
It is worth emphasising that the pharmacokinetic interactions described above, while leading to measurable increases in loratadine plasma concentrations, have not translated into clinically significant adverse outcomes in controlled studies. The FDA and EMA product labelling for loratadine notes the interactions with ketoconazole, erythromycin, and cimetidine but does not mandate dose adjustments for these combinations. This distinguishes loratadine from some other antihistamines (such as the now-withdrawn terfenadine and astemizole) where CYP3A4 inhibition led to dangerous cardiac arrhythmias.
Patients taking multiple medications metabolised by CYP3A4 or CYP2D6 should nonetheless mention their loratadine use to their healthcare provider, particularly when starting a new medication. This is especially important for patients on potent CYP3A4 inhibitors such as itraconazole, voriconazole, clarithromycin, ritonavir, and other protease inhibitors used in HIV therapy, where the magnitude of loratadine level increases may be substantial even if the clinical consequences have been reassuring in studied combinations.
What Is the Correct Dosage of Loratadine?
Loratadine should always be taken exactly as described in the patient information leaflet or as directed by your healthcare provider, pharmacist, or nurse. The medication is taken once daily, as its combined pharmacological activity (parent drug plus active metabolite desloratadine) provides effective symptom relief for a full 24-hour period. Loratadine can be taken at any time of day, with or without food. However, for optimal allergy relief, particularly in seasonal allergic rhinitis, taking it at the same time each day helps maintain consistent plasma levels.
| Patient Group | Dose | Formulation | Frequency |
|---|---|---|---|
| Adults & adolescents (>30 kg) | 10 mg | Tablet or 10 ml syrup | Once daily |
| Children 6–12 years (>30 kg) | 10 mg | Tablet or 10 ml syrup | Once daily |
| Children 2–12 years (≤30 kg) | 5 mg | 5 ml syrup | Once daily |
| Severe liver impairment | 10 mg | Tablet or 10 ml syrup | Every other day |
| Renal impairment | 10 mg | Tablet or 10 ml syrup | Once daily (no adjustment needed) |
| Elderly | 10 mg | Tablet or 10 ml syrup | Once daily (no adjustment needed) |
Adults
The standard adult dose of loratadine is 10 mg once daily, taken as a single tablet or 10 ml of the oral syrup formulation. Loratadine tablets should be swallowed whole with water, though the syrup can be taken without additional fluids. The onset of symptomatic relief typically occurs within 1 to 3 hours after oral administration, with peak antihistaminic activity reached within 8 to 12 hours. The effect persists for at least 24 hours, supporting the convenient once-daily dosing regimen.
For patients self-treating with over-the-counter loratadine, it is recommended to consult a healthcare provider if symptoms do not improve after 7 days of use, or if symptoms worsen. If continuous treatment is needed for longer than 3 months, a medical evaluation should be sought to investigate whether the symptoms have an underlying cause requiring different management. There is no established maximum duration of loratadine use, and many patients with chronic conditions such as perennial allergic rhinitis or chronic urticaria use the medication for extended periods under medical supervision.
Children
Dosing in children is based on body weight rather than age alone. Children weighing 30 kg or less should take 5 mg (equivalent to 5 ml of syrup) once daily. Children weighing more than 30 kg take the full adult dose of 10 mg (equivalent to 10 ml of syrup or one tablet) once daily. The tablet formulation is generally recommended for children aged 6 years and older, while the syrup is preferred for younger children (aged 2 to 5 years) who may have difficulty swallowing tablets.
Loratadine is not recommended for children under 2 years of age due to insufficient data on safety and efficacy in this age group. For children between 2 and 6 years, the syrup formulation should always be used with the calibrated measuring device provided in the packaging. Household spoons vary significantly in volume and should never be used for medication dosing, as this can lead to under- or overdosing.
Elderly
No dose adjustment is required for elderly patients. Pharmacokinetic studies in healthy elderly volunteers have not demonstrated clinically significant differences in the absorption, distribution, metabolism, or elimination of loratadine compared to younger adults. The standard dose of 10 mg once daily is appropriate for elderly patients, provided there is no significant hepatic impairment that would warrant dose reduction. Elderly patients should, however, be monitored for drowsiness, as age-related changes in pharmacodynamic sensitivity may occasionally increase susceptibility to sedative effects.
Missed Dose
If you forget to take a dose of loratadine, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to compensate for a missed one. Missing a single dose of loratadine is unlikely to cause a significant return of symptoms, as the active metabolite desloratadine has a long half-life of approximately 28 hours, providing some residual antihistaminic activity.
Overdose
In the event of an overdose, or if a child has accidentally ingested loratadine, contact your local poison control centre or seek immediate medical attention. Symptoms of loratadine overdose may include headache, rapid heartbeat (tachycardia), and drowsiness. In clinical overdose experience, no serious adverse outcomes have been reported with loratadine, and the drug has a wide margin of safety. Treatment of overdose is generally supportive and symptomatic, as there is no specific antidote. Activated charcoal may be considered if the ingestion is recent (within 1 hour) and the amount consumed is substantially above the therapeutic dose.
If you suspect a loratadine overdose, particularly in a child, contact your local poison control centre or emergency services immediately. While serious complications are uncommon, rapid heartbeat and drowsiness may occur and require medical monitoring.
What Are the Side Effects of Loratadine?
Like all medicines, loratadine can cause side effects, although not everyone experiences them. Loratadine is considered one of the best-tolerated antihistamines available, with an overall adverse event profile that is similar to placebo in most clinical trials. The following side effects have been reported during clinical studies and post-marketing surveillance. Side effects are categorised by frequency according to the standard MedDRA convention used by regulatory agencies worldwide.
It is important to note that many of the side effects listed below, particularly the common ones such as headache and drowsiness, occur at rates only slightly higher than those observed with placebo in clinical trials. This means that some individuals may attribute symptoms to loratadine that are actually unrelated to the medication. However, if you experience any persistent or bothersome symptoms while taking loratadine, you should consult your healthcare provider.
Common Side Effects in Adults (≥12 years)
May affect up to 1 in 10 people
- Drowsiness or somnolence
- Headache
- Increased appetite
- Difficulty sleeping (insomnia)
Common Side Effects in Children (2–12 years)
May affect up to 1 in 10 children
- Headache
- Nervousness or restlessness
- Fatigue or tiredness
Very Rare Side Effects
May affect up to 1 in 10,000 people
- Severe allergic reaction (anaphylaxis), including swelling of the face, lips, tongue, or throat
- Dizziness
- Seizures (convulsions)
- Irregular or rapid heartbeat (tachycardia, palpitations)
- Nausea
- Dry mouth
- Stomach upset (gastritis)
- Liver function abnormalities (hepatitis)
- Hair loss (alopecia)
- Skin rash
- Fatigue
Frequency Not Known
Cannot be estimated from available data
- Weight gain
Understanding Side Effect Frequency
The frequency categories above follow the convention used by the European Medicines Agency (EMA) and adopted by regulatory authorities worldwide. "Common" means that between 1 in 100 and 1 in 10 people may experience the effect; "very rare" means fewer than 1 in 10,000 people. It is reassuring that the vast majority of reported side effects for loratadine fall into the "very rare" category, reflecting the drug's established and favourable safety profile over decades of widespread global use.
In large-scale clinical trials comparing loratadine 10 mg to placebo, the incidence of drowsiness with loratadine was only marginally higher than with placebo (approximately 8% versus 6% in adult studies). This small difference underscores why loratadine is classified as a "non-drowsy" antihistamine, even though some individuals may occasionally experience mild sleepiness. The sedation rate with loratadine is substantially lower than with first-generation antihistamines such as diphenhydramine (where drowsiness affects up to 50% of users) and also lower than with cetirizine (where drowsiness is reported in approximately 10% of users).
When to Seek Medical Attention
While most side effects of loratadine are mild and transient, certain symptoms require immediate medical attention. Seek emergency medical help if you experience signs of a severe allergic reaction, including swelling of the face, lips, tongue, or throat; difficulty breathing or swallowing; or widespread skin rash with itching. You should also contact your healthcare provider promptly if you experience a rapid, irregular, or pounding heartbeat, as cardiac arrhythmias, although extremely rare with loratadine, require medical evaluation.
If you notice any side effects not mentioned in this guide, or if any of the listed side effects become severe or persistent, consult your doctor, pharmacist, or nurse. Reporting side effects to your national pharmacovigilance agency contributes to the ongoing monitoring of drug safety and helps ensure the benefit-risk balance of loratadine remains favourable. In the United Kingdom, adverse reactions can be reported through the Yellow Card Scheme; in the United States, through the FDA MedWatch programme; and in other countries, through the relevant national authority.
How Should You Store Loratadine?
Proper storage of loratadine ensures the medication retains its full potency and safety throughout its shelf life. Loratadine tablets should be stored at room temperature, ideally below 25°C (77°F), in a dry place away from direct sunlight and moisture. Keep the tablets in their original blister packaging until the time of use, as this provides the best protection against environmental factors that could degrade the medication.
The syrup formulation of loratadine requires slightly different storage considerations. The syrup should not be frozen and should be protected from light by keeping the bottle in its outer carton when not in use. Once the bottle has been opened, the syrup should be used within 1 month, after which it should be discarded even if there is remaining product. This is a precautionary measure to ensure microbiological safety and pharmaceutical stability of the oral solution.
Both formulations should be kept out of the sight and reach of children. Child-resistant closures on the syrup bottle provide an additional safety measure, but they are not a substitute for keeping the medication in a secure location. Do not use loratadine after the expiry date printed on the carton or blister pack. The expiry date refers to the last day of the indicated month.
Do not dispose of loratadine or any other medication by flushing it down the toilet or throwing it in household waste. Return unused or expired medication to a pharmacy for safe disposal. Many pharmacies participate in take-back programmes that ensure medications are disposed of in an environmentally responsible manner, preventing contamination of waterways and soil.
What Does Loratadine Contain?
Active Ingredient
The active pharmaceutical ingredient in all loratadine formulations is loratadine itself, a tricyclic piperidine compound with the chemical name ethyl 4-(8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-ylidene)-1-piperidinecarboxylate. Each standard tablet contains 10 mg of loratadine, while the syrup formulation contains 1 mg/ml (equivalent to 10 mg per 10 ml). Loratadine is a white to off-white powder that is practically insoluble in water but freely soluble in organic solvents such as acetone and methanol.
Tablet Formulation Excipients
The inactive ingredients in loratadine tablets vary by manufacturer but commonly include lactose monohydrate, maize starch (corn starch), magnesium stearate, and other standard pharmaceutical excipients. Patients with lactose intolerance should check the specific product's patient information leaflet or consult a pharmacist, as the lactose content per tablet is typically small (less than 100 mg) but may be relevant for individuals with severe intolerance or rare hereditary conditions of galactose intolerance or glucose-galactose malabsorption.
Syrup Formulation Excipients
The loratadine syrup formulation contains a variety of inactive ingredients designed to ensure stability, palatability, and appropriate pharmaceutical properties. These commonly include liquid maltitol (as a sweetener and vehicle), sorbitol (as a sweetener), propylene glycol (as a solvent and stabiliser), glycerol, phosphoric acid (pH adjuster), sodium benzoate (preservative), sucralose (artificial sweetener), fruit flavouring, disodium edetate (chelating agent), and purified water.
Patients with hereditary fructose intolerance should be aware that sorbitol is a source of fructose. Those with this condition should not use the syrup formulation without medical advice, and the tablet formulation may be a more suitable alternative. The sodium content of the syrup is less than 1 mmol (23 mg) per 5 ml dose, meaning it is essentially "sodium-free" and suitable for patients on sodium-restricted diets. The propylene glycol content is approximately 50 mg/ml (250 mg per 5 ml dose), which is within established safety limits for oral pharmaceutical preparations.
Frequently Asked Questions About Loratadine
Loratadine is a second-generation, non-drowsy antihistamine used to relieve symptoms of allergic conditions including seasonal allergic rhinitis (hay fever), perennial allergic rhinitis, and chronic idiopathic urticaria (hives). It helps with sneezing, runny nose, itchy or watery eyes, nasal congestion, and itching of the skin. Available over the counter in most countries, it comes as tablets (10 mg) and syrup (1 mg/ml) for use by adults and children from 2 years of age.
Loratadine is classified as a non-sedating antihistamine and at the recommended dose of 10 mg, clinical studies have not demonstrated significant sedation or impairment of driving ability compared to placebo. PET studies show that loratadine occupies less than 30% of brain H1 receptors, well below the threshold for drowsiness. However, occasional cases of mild drowsiness have been reported, particularly at the start of treatment. Compared to cetirizine, loratadine is generally considered less sedating.
Yes, loratadine can be taken once daily for ongoing allergy symptoms. For self-medication, consult a healthcare provider if symptoms persist beyond 7 days without improvement or if continuous use beyond 3 months is needed. Long-term safety data supports the use of loratadine for extended periods in conditions like perennial allergic rhinitis and chronic urticaria, under medical supervision. There is no evidence of tolerance (reduced effectiveness) developing with continued use.
Clinical studies have not demonstrated that loratadine at recommended doses potentiates the effects of alcohol. Unlike first-generation antihistamines, loratadine does not appear to enhance alcohol-induced sedation or psychomotor impairment. However, as with all medications, it is prudent to exercise caution, particularly with heavy alcohol consumption, as individual responses may vary.
Loratadine should not be taken during pregnancy unless recommended by a healthcare provider. While animal studies and observational data have not identified a consistent pattern of birth defects, there are limited well-controlled studies in pregnant women. Loratadine is also excreted in breast milk, so breastfeeding mothers should seek medical advice before use. If antihistamine treatment is necessary during pregnancy or breastfeeding, a healthcare provider can help determine the most appropriate option.
Both loratadine and cetirizine are second-generation antihistamines used for allergies and hives. Loratadine is generally considered less sedating than cetirizine at standard doses, as PET studies show lower brain H1 receptor occupancy. Cetirizine has a slightly faster onset of action. Loratadine is extensively metabolised in the liver (via CYP3A4 and CYP2D6), making it potentially more susceptible to drug interactions, while cetirizine is primarily excreted unchanged by the kidneys, requiring dose adjustment in renal impairment. Both are effective first-line treatments, and the choice depends on individual tolerance and concurrent medications.
Yes, loratadine is approved for children aged 2 years and older. The syrup formulation (1 mg/ml) is recommended for younger children. Children weighing 30 kg or less take 5 ml (5 mg) once daily, while those over 30 kg take 10 ml (10 mg) once daily. The tablet formulation (10 mg) is generally suitable from age 6. Loratadine is not recommended for children under 2 years. Always use the calibrated measuring device provided with the product for accurate dosing.
References & Sources
All information in this article is based on evidence-based international medical guidelines and peer-reviewed research. The following sources were consulted during the preparation and review of this content:
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