Loratadine (Claritin) is a drug used to relieve symptoms of allergies such as sneezing, runny nose, redness, or itchy eyes, nose, or throat, etc. Learn about its uses, dosage, drug warnings, side effects, precautions, drug interactions, and more.
Loratadine (Claritin) is an over-the-counter medicine used to relieve the symptoms of hay fever (allergy to dust, pollen, or other substances in the air), upper respiratory tract allergies, and other allergies such as sneezing, itching, watery eyes, and runny nose. It can also be used to relieve itching from hives. However, Loratadine does not prevent hives or treat severe allergic reactions like anaphylaxis. The drug Loratadine in the form of tablets or capsules should not be used in children under six years of age. Whereas in cases of liquid or chewable tablets, it should not be used in children under two years of age without a doctor's advice
Loratadine is an antihistamine and is also available in combination with Pseudoephedrine (Sudafed, others). The monograph always includes only the information on Loratadine, so if you are taking a combination product (Loratadine and Pseudoephedrine), read the details mentioned on the package label, or you can ask the physician or pharmacist for more information.
Loratadine (Claritin) belongs to the class of drugs called antihistamines. Antihistamines work by blocking or reducing the effects of the natural chemical histamine, which is a substance in the body that causes allergic symptoms of sneezing, itching, watery eyes, runny nose, etc.
Usage of Loratadine: The drug can be used as an over-the-counter drug to self-treat some allergic symptoms but the directions on the product packaging should be read properly before that. If the doctor has prescribed the drug, it is important to follow all the instructions given by the doctor.
Loratadine is used in the treatment of the following conditions-
1. Hay Fever or Allergic Rhinitis - A type of inflammation in the nose, and Loratadine is used to relieve nasal and non-nasal symptoms that occur when the immune system overreacts to allergens in the air.
2. Urticaria - Otherwise called hives that cause red, itchy welts due to a skin reaction. It is considered chronic hives if the welts persist for more than six weeks. Loratadine is used to treat skin hives and itching in people with chronic skin reactions.
3. Physical Urticaria - A condition in which allergic skin rashes (red allergic skin lesions and pruritus) are produced by,
Contact with chemicals.
Contact with plants.
4. Serious Allergic Reaction (Anaphylaxis) - It is a potentially life-threatening allergic reaction, which could occur within seconds or minutes of exposure to something you are allergic to.
5. Upper Respiratory Allergies -
Runny nose or stuffy nose.
Itchy and watery eyes.
Itching of the nose or throat.
Swelling around the eyes.
Loratadine should not be taken if a person is allergic to Desloratadine (Clarinex) or Loratadine. It is important to inform doctors about any drug allergies before starting the drug.
Some chewable dosage forms of Loratadine also contain phenylalanine which is not indicated in cases of phenylketonuria (PKU). This is a birth defect that leads to the accumulation of phenylalanine in the body.
The drug should also be precisely taken in cases of asthma, liver, or kidney diseases. The doctor should be informed prior to any such condition.
The drug should not be taken if the allergy test of an individual is pending as the drug may lead to false reports.
In cases of epilepsy or history of seizures as it may cause it as one of the side effects.
Allergic rhinitis is an allergic reaction to allergens such as pollen grains (the most common one). It is also known as hay fever. It is studied that almost 30 % of the world population may have allergic rhinitis. Other than pollen the allergens are dust mites, animal dander, cat saliva, or molds.
The Common Symptoms of the Disease Are:
A runny nose.
Stuffy nose which may also cause difficulty in breathing.
An itchy nose causing irritation.
Sneezing which can be very frequent.
Sore or scratchy throat which causes discomfort.
Watery and itchy eyes particularly along with continuous sneezing.
Dark circles under the eyes due to disturbed sleep.
Frequently occurring headaches.
Eczema: it is a type of symptom where there is extremely dry, itchy skin that can blister and weep.
Urticaria (also known as hives) which lead to the formation of itchy, raised welts on the skin. These can be pink, red, or flesh-colored which may even sometimes sting or hurt.
Excessive fatigue and weakness.
Unwillingness to perform daily routine works.
There are two types of allergic rhinitis, which are seasonal and perennial.
Seasonal allergies usually occur during the spring season and are generally in response to outdoor allergens like pollen.
Perennial allergies can occur anytime in response to indoor substances like pet dander or dust mites.
Cold weather or temperatures.
Lifestyle Changes to Avoid Hay Fever:
There are some important points that should be kept in mind to prevent Hay fever in day-to-day life:
1. While Outside the House:
It is advised not to cut grasses or even walk on grasses.
Vaseline can be applied around the nostril to trap pollen.
Preventing the trap of pollen into the eyes by wearing wrap-around glasses.
After coming back from outside it is important to take shower and wash the clothes to prevent pollen contact.
2. While Inside the House:
The house should be cleaned and vacuumed regularly.
The windows and doors should be closed as much as possible.
Fresh flowers should not be kept in the house.
Smoking should be avoided or passive smoking should also be avoided as it worse the symptoms.
Before Taking the Drug:
Histamine is a natural chemical substance of the body that causes symptoms of allergy. Mast cells are histamine-storing cells, and they release histamine to attach to other cells with receptors for histamine on their surfaces. This released histamine starts stimulating the cells to release chemicals that are associated with allergy, including hives, itching, and redness.
Loratadine is an FDA-approved long-acting drug that is used for the treatment of allergies as it blocks the H1 type of histamine receptor and it prevents cell activation with H1 receptors by histamine. Unlike some other antihistamines, Loratadine is a non-sedating drug that does not enter the brain from the blood. Therefore, it does not cause drowsiness when taken at recommended doses.
Onset Of Action:
The time required for Loratadine to start acting varies until the person is recommended with daily dosing. It generally starts working within 1 to 3 hours and reaches its peak at approximately after 8 to 12 hours of taking the drug. The duration of action is at least 24 hours, so it is meant to be taken once a day.
Avoid taking this medicine after it expires. The listed expiration dates for over-the-counter medicines like Loratadine (Claritin) is typically around two and a half years after manufacturing, or you can verify the expiry date printed on the back of the pack before taking medicine.
Information to Be Given to the Doctor: Before starting the drug, it is essential to inform the doctor about a few important points:
Drug Allergies: The presenceof any previous drug allergy should be informed before starting the drug to prevent any complications or side effects.
Diseases: The history of any kidney or liver disease should be informed to the healthcare professionals as it may affect the metabolism of excretion of the drug.
Phenylketonuria: Some tablets of Loratadine may contain phenylalanine which may worsen the condition of phenylketonuria. Thus it is important to inform the doctor about the disease.
Pregnancy or Breastfeeding: Inform the doctor about any of the two conditions before starting the drug.
The Doses Depend on the Individual:
The dose of Loratadine also depends on the body weight and age of the individual. Children between the age of 6 to 12 can take Loratadine tablets only when their body weight is more than 30 kgs. In cases of children less than 6 years or body weight less than 30 kgs, it is advised to give liquid Loratadine. Even in cases of people suffering from liver diseases, the dose should be less than normal.
Preparations and Doses:
Loratadine is available in the following preparations.
Loratadine Usual Dosage for Adults:
Loratadine Usual Dosage for Children:
Loratadine is available as a syrup (liquid), a tablet, and disintegrating (dissolving) tablet. It is taken once a day orally with or without food. Use it exactly as directed on the package label, and ask your doctor or pharmacist to explain any part you do not understand.
Do not take more or less of it or for a longer time than recommended by the doctor. If you take more than directed, you may experience drowsiness.
Try to avoid using this medication if you come to see the safety seal is open or torn and also, store this drug at room temperature away from moisture and heat.
The drug should not be prescribed to children less than two years of age. In children older than two years, the drug should be given strictly according to the doctor’s advice as it may be fatal.
The dose of the drug for children should be depending on the age and the body weight of the child.
You should swallow the whole pill and do not crush, chew, or break the regular tablet. Before swallowing the chewable tablet, it must be chewed.
Always measure liquid medicine with the dosing syringe or medicine cup and if you do not have any of these dose-measuring devices, ask your pharmacist for one.
On taking an oral rapidly disintegrating tablet-
Before removing the tablet from the blister package, study the package directions to follow it.
Do not break the tablet.
Do not push the tablet through the foil, as you can damage the tablet.
After the tablet is removed from the blister package, immediately place it on the tongue and close the mouth.
The tablet gets dissolved quickly and can be swallowed with or without water.
Do not use Loratadine to treat bruised hives that are of unusual color and do not itch. It is better to consult a doctor if hives do not improve within three days of treatment or if it lasts for more than 6 weeks.
If you develop any of the following symptoms on taking Loratadine to treat hives, get emergency medical help-
Loss of consciousness.
Swelling of the tongue.
Swelling in and around the mouth.
The above-mentioned are symptoms of anaphylaxis which is a life-threatening allergic reaction. If the doctor suspects these symptoms, then he may prescribe an Epinephrine injector (EpiPen).
Loratadine produces some side effects which need to be handled as the drug is necessary for the suppression of allergic effects. Some of the symptoms are-
Sleepiness or Drowsiness: Although Loratadine is a non-drowsy anti-inflammatory, if it leads to sleepiness in a patient, it should be avoided. Other anti-inflammatory actions should be taken.
Headaches: In such cases, it is important to consume a lot of fluids and rest. If the headache is severe, painkillers can be taken on the advice of a pharmacist.
It is important to take the missed dose as soon as you remember it, but if it is almost time for the next dose, you can skip the missed dose and start continuing with the regular dosing schedule. In order to compensate for a missed one, do not take a double dose.
1. Do not alter the dosage by yourself; only a doctor can determine if your dose needs to be altered.
2. Do not take more than the recommended amount while using this product because taking more than the recommended amount may cause drowsiness.
3. Seek medical help right away when you become allergic to this medication.
4. If pregnant or planning to get pregnant, ask the doctor before taking the medication.
5. Always tell your physician if you are breastfeeding a baby. It is not expected to harm an unborn baby, but it can pass into breast milk, and it is considered compatible with breastfeeding.
6. Keep it out of children's reach and do not give this medicine to children younger than 2 years old. Before giving a child cough or cold medicine, it is better to ask a doctor. When cough and cold medicines are misused in very young children, it can lead to death.
7. Tell your doctor what medications, vitamins, nutritional supplements, and herbal products you are taking or planning to take.
8. Follow restrictions on food, beverages, or other activities along with the drug when instructed by the doctor.
The symptoms of overdose of Loratadine include drowsiness, headache, and fast or pounding of the heartbeat.
The symptoms of overdose of Loratadine include drowsiness, headache, and fast or pounding of the heartbeat.
It is not recommended to consume or prescribe two types of antihistamines together as both of them may function differently and may produce different side effects. It is advised to stop one antihistamine before starting the other one.
A. Side Effects in Children:
Side Effects on Children Between 2–5 Years of Age Receiving Oral Solution-
Epistaxis - Bleeding from the nose.
Stomatitis - Inflammation inside the mouth, making it difficult to eat, talk, etc.
Tooth disorder - Damage to the tooth surface, leading to cavities.
Pharyngitis - Swelling between the voice box and tonsils.
Side Effects on Children Between 6–12 Years of Age Receiving Oral Solution-
Upper respiratory tract infections.
Conjunctivitis - Infection or allergy on the outer membrane of the eyeball.
Dysphonia (hoarseness of the voice).
Hyperkinesia - Children marked by hyperactivity and inability to concentrate.
Side Effects on ≥12 Years of Age Receiving Conventional or Orally Disintegrating Tablets-
Somnolence - Feeling of drowsiness and ready to fall asleep.
B. Side Effects in Adults:
Most Common Side Effects-
The most common side effects of Loratadine include,
If you come across these symptoms, consult a doctor.
Serious Side Effects-
The serious side effects caused by Loratadine are,
Uneven heart rate.
Swelling of lips, throat, and tongue.
Swelling of ankles or lower legs.
Swelling of hands, feet, and arms.
Difficulty in breathing and swallowing.
Swelling of the eyes and face.
If you notice any of these symptoms, stop using the medicine, call your doctor immediately and get medical help right away. All these are not a complete list of side effects, and this drug causes some other side effects.
For the Doctors:
Loratadine is a piperidine histamine H1- receptor antagonist with some anti-allergic properties but does not have sedative effects. Loratadine is approved by the FDA (The United States Food and Drug Administration) to treat and relieve allergic rhinitis (hay fever) and allergic skin known as urticaria. Loratadine is a second-generation antihistamine that is used in a variety of conditions such as watery eyes, runny nose, sneezing, and pruritus. Loratadine can be used as a prescribed medicine or as an over-the-counter drug in both generic and branded forms. The drug can be administered accordingly to children above the age of two, adults, and older patients.
Like all the second-generation antihistamines, Loratadine is selective in nature for peripheral H1 receptors. It does not penetrate through the blood-brain barrier to the central nervous system and also has a poor affinity for CNS H1 receptors. This leads to a lack of CNS depressant quality in the drug and prevents symptoms such as sedation, drowsiness, and impaired psychomotor functions.
Mechanism of Action:
Loratadine is a second-generation, long-acting tricyclic antihistamine that is non-sedating in nature. The drug has selective antagonist properties to peripheral histamine H1 receptors. Loratadine inhibits the H1 receptors which are primarily located on the respiratory smooth muscles, vascular endothelial cells, the gastrointestinal tract, and the immune cells of the body. Unlike the first-generation antihistamines such as Diphenhydramine, Loratadine is a competitive histamine antagonist which does not cross the blood-brain barrier. Hence Loratadine does not affect the brain or neurons of the central nervous system which apparently prevents daytime drowsiness or sedation.
Loratadine binds to different receptors of histamine on the tissues and leads to a decrease in vascular permeability (prevents edema and flushing), decreases the smooth muscle tone (bronchodilation), and decreases the activation of peripheral nociceptive receptors. If the second generation Loratadine is given in higher concentration, it inhibits the histamine release from the mast cells and the basophils which leads to reduction of ICAM-1 expression in epithelial cells and thus inhibits the type 1 hypersensitivity reaction. Loratadine can be called an “inverse agonist” as compared to a histamine antagonist and can reduce the severity of histamine-mediated symptoms in the body. Loranatide possesses a rapid onset of action as it works within 1 hour to 3 hours of administration and reaches its peak effect within 8 hours to 12 hours. The elimination of the drug occurs through both the fecal and renal routes.
Loratadine can be absorbed rapidly and achieves peak plasma concentration within 1 hour to 2 hours and its metabolite achieves peak plasma concentration in 3 hours to 4 hours.
In case of rapid dissolve formulation, the pharmacokinetic parameters of Loratadine are: Cmax = 2.56 ng/mL, Tmax = 1.14 hrs and AUC = 6.14 ng x hr/mL.
In cases of conventional formulation, the pharmacokinetic parameters of Loratadine are: Cmax = .11 ng/mL, Tmax = 1.00 hr, and AUC = 4.64 ng x hr/mL.
The Volume of Distribution: For Loratadine, the volume of distribution is 120 L/kg.
Protein Binding: Loratadine has a protein binding affinity of up to 97 % to 99 % to the plasma proteins.
Loratadine undergoes first-pass metabolism in the liver and is primarily metabolized by CYP3A4, CYP2D6, CYP1A1, and CYP3A5. CYP3A4 and CYP2D6 are responsible for metabolizing Loratadine to descarboethoxyloratadine. This metabolite of Loratadine is four times more pharmacologically active than Loratadine.
The descarboethoxyloratadine is first glucuronidated by UGT2B10 and then hydroxylated by CYP2C8 to form 3- hydroxy desloratadine. At last, the glucuronidation of 3-hydroxy desloratadine facilitates excretion.
Route of Elimination:
It is observed that over a period of 10 days, 40 % of Loratadine is excreted in the urine and 42 % can be excreted out in the feces. The elimination half-life for Loratadine is approximately 10 hours and for descarboethoxyloratadine, it is 20 hours.
The clearance of loratadine after a single oral dose of 20 mg is 12 L/h/kg and for the 40 mg dose it is 9 L/h/kg. P-glycoprotein is involved in the clearance of many second-generation antihistamines including the Loratadine. P-glycoprotein does not participate in clearing the first-generation antihistamines which helps to explain their adverse effect on the central nervous system. It is noted that antihistamines with more affinity to P-glycoprotein have fewer adverse effects compared to other antihistamines.
Loratadine has very less adverse effects but some of the symptoms reported are drowsiness, insomnia (difficulty in sleeping), headache, fatigue, and rashes. Loratadine overdose can lead to symptoms such as tachycardia, agitation, headache, and drowsiness.
Prescription drugs, over-the-counter medicines, vitamins, and herbal products can interact with Loratadine (Claritin). It is important to tell the health care professional about all medicines that we take and any medicine you start or stop using. It is always important to look for the following drugs when you take Loratadine as it may cause drug interactions.
Amphetamine (it reduces the sedative and the stimulatory qualities of Loratadine).
Cocaine (it increases the anticholinergic properties of Loratadine).
Epinephrine (Loratadine increases the therapeutic efficacy of epinephrine when used in combination).
Ketorolac (the metabolism of ketorolac reduces when it is combined with Loratadine).
Ofloxacin (the excretion rate of ofloxacin reduces when it is combined with Loratadine and thus the serum concentration increases).
Phenytoin (the metabolism of phenytoin reduces when it is combined with Loratadine).
The following medications increase the blood concentration of Loratadine (Claritin) by inhibiting the elimination of Loratadine and result in increased adverse events from Loratadine. So, tell your doctor if you are taking any of these medications.
Cimetidine (it helps to reduce the excretion rate of Loratadine and thus results in higher serum levels).
Ketoconazole (it is used to treat fungal infections and should be avoided with Loratadine).
Caution should be taken while taking the following drugs as it reduces blood levels of Loratadine (Claritin).
St. John's wort.
Carbamazepine (the drug increases the metabolism of Loratadine when given together).
Clinical Trials for Loratadine:
A study about the onset of action of Loratadine and Fexofenatide in participants suffering from seasonal allergic rhinitis:
Objective of the Study: This study was done to determine the efficacy of the onset of action of the two drugs which are used over-the-counter. In this study, the participants underwent sensitization exposure to mountain cedar pollen which helps to create an allergic response.
Number of Participants: 255 participants enrolled in this study.
Primary Purpose: The primary purpose of the study is the treatment of the participants.
Results: The mean major symptom complex (MSC) helps to evaluate the treatment status of the participants.
Study about the efficacy and safety of Loratadine (10 mg once every day), Terfenadine (60 mg twice daily), and placebo for the treatment of seasonal allergic rhinitis. A total of 317 participants were given 10 mg Loratadine and Terfenadine 60 mg for one dose and two doses respectively or a placebo in a 14-day, double-blind, randomized study of seasonal allergic rhinitis.
Results: the Loratadine was superior to Terfenadine 60 mg and the placebo over the effect on allergic rhinitis.
Loratadine in Pregnancy: Loratadine can be prescribed to pregnant women as there are no adverse effects studied about the drug on the mother or the fetus.
Loratadine in Breastfeeding: Loratadine can be given during breastfeeding if the baby is healthy. It was proposed by the studies that only a very tiny amount of drug passes the breast milk.
Loratadine in Geriatric Patients:The drug is safe to use in the older population as it has no major side effects.
The common brandor trade names of Loratadine are,-
Ohm Allergy Relief.
QlearQuil All Day and Night.
Allergy Relief 24 Hour.
Allergy Relief Tablets.
Children's Allergy Relief 24 Hour.
Children's Claritin Allergy.
Claritin 24-Hour Allergy.
Claritin Hives Relief.
Dimetapp Children's ND Non-Drowsy Allergy.
Last reviewed at:
04 Jul 2022 - 17 min read
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