Loratadine

Loratadine is an antihistamine medication used to treat symptoms of allergies, such as runny nose, sneezing, itching, and watery eyes. It is available over-the-counter and by prescription in some countries. Loratadine works by blocking the action of histamine, a chemical produced by the body in response to an allergen. By blocking histamine, loratadine helps to alleviate allergy symptoms.

Loratadine is well absorbed from the gastrointestinal tract after oral administration. The peak plasma concentration is achieved within 1 to 2 hours after ingestion. Loratadine is highly bound to plasma proteins, with an approximate binding of 97%. It is distributed throughout the body, including the central nervous system, but has limited ability to cross the blood-brain barrier.Loratadine undergoes extensive first-pass metabolism in the liver, mainly by the cytochrome P450 enzyme CYP3A4. It is metabolized to an active metabolite called desloratadine, which has a longer half-life than loratadine and is responsible for the majority of the drug's antihistaminic effect. Loratadine and its metabolites are eliminated primarily through the urine, with about 80% of the dose excreted in the urine within 10 days after administration

Tmax of Loratadine is approximately 1 to 2 hours after oral administration.

Cmax of Loratadine after a single oral dose 13.5 ng/mL.

Loratadine shows common side effects like Headache, Dry mouth, Fatigue or drowsiness, Nausea, Stomach upset, Nervousness, Difficulty sleeping and Skin rash or itching.

Loratadine is available in Film coated tablet.

Loratadine is available in India, Germany, Canada, France.

Loratadine is a second-generation antihistamine that works by blocking the action of histamine, a chemical mediator that is released in response to an allergen or an immune trigger. Histamine binds to H1 receptors on target cells, causing a cascade of reactions that lead to the production of allergy symptoms, such as itching, sneezing, runny nose, and watery eyes.

Loratadine is available in the form of film coated tablets.

Loratadine is an effective and well-tolerated antihistamine that can provide rapid relief of allergy symptoms. Loratadine is a widely used medication that provides a number of benefits for people suffering from allergies and related conditions.

Loratadine is approved for use in the following clinical indications

Seasonal allergies: Loratadine is commonly used to treat seasonal allergies, such as hay fever, which are caused by exposure to outdoor allergens such as pollen and mold spores.

Year-round allergies: Loratadine can also be used to treat year-round allergies, such as allergic rhinitis, which are caused by indoor allergens such as dust mites, pet dander, and mold.

Urticaria (hives): Loratadine can be used to relieve the symptoms of urticaria, a skin condition characterized by red, itchy, and swollen hives that can be caused by an allergic reaction or other triggers.

Allergic conjunctivitis: Loratadine can also be used to relieve the symptoms of allergic conjunctivitis, an inflammation of the eyes caused by an allergic reaction to an irritant such as pollen, dust, or pet dander.

Oral: Administer with water 1 hour before or 2 hours after intake of food or fruit juices.

Allergic rhinitis

Adult: For symptomatic relief of allergic rhino-conjunctivitis (seasonal allergic rhinitis and perennial allergic rhinitis): As conventional tab: 10 mg once daily. Limit treatment to the period of exposure to allergens. Seasonal allergic rhinitis: Discontinue treatment after the symptoms have resolved, reinitiate treatment if symptoms reappear. Perennial allergic rhinitis: Treatment may be continued during allergen exposure periods.

Oral

Urticaria

Adult: As conventional tab: 20 mg once daily. Treatment duration may vary depending on the type, duration, and course of the complaints.

Child: 6-11 years weighing at least 20 kg: As orodispersible tab and oral solution: 10 mg once daily. ≥12 years Same as adult dose.

Loratadine is available in the dosage strength of

• 10 mg.

Loratadine is available in the form of tablets.

• Dosage Adjustment for Pediatric Patients

Seasonal allergic rhinitis:

Child: 6-11 years weighing at least 20 kg and Children ≥12 years and Adolescents:

Oral: Refer to adult dosing

Take after eating and with a full glass of water to decrease gastric upset.

Hypersensitivity: It should not be used in patients who have a known hypersensitivity or allergy to Loratadine or any other antihistamine drugs.

While loratadine is generally considered safe and well-tolerated, there are some important warnings and precautions to keep in mind when using this medication. These include:

Allergic reactions: If you experience symptoms of an allergic reaction, such as difficulty breathing, swelling of the face, lips, tongue or throat, or a skin rash, stop using loratadine immediately and seek medical attention.

Kidney or liver disease: If you have kidney or liver disease, speak with your healthcare provider before using loratadine, as these conditions may affect the way the drug is metabolized and eliminated from your body.

Central nervous system depression: Loratadine is generally non-sedating, but in rare cases, it may cause drowsiness or impair cognitive function. If you experience any of these symptoms, avoid driving or operating heavy machinery.

Elderly patients: Elderly patients may be more susceptible to the side effects of loratadine, so they should use the medication with caution and under the guidance of a healthcare provider.

Other medications: Loratadine may interact with other medications, including prescription drugs, over-the-counter products, and herbal supplements. Speak with your healthcare provider or pharmacist before using loratadine if you are taking any other medications.

Pregnancy and breastfeeding: Although loratadine is generally considered safe during pregnancy and breastfeeding, speak with your healthcare provider before using loratadine if you are pregnant, planning to become pregnant, or breastfeeding.

Overall, loratadine is a safe and effective medication for the relief of allergy symptoms, but it is important to use it as directed and to speak with your healthcare provider if you have any concerns or questions about its use.

Loratadine may cause liver problems, and using it with substantial quantities of ethanol may increase that risk.

Loratadine is present in breast milk.

Concentrations of Loratadine in breast milk increase with supplementation. When used as a dietary supplement, the recommended dietary allowance of Loratadine is increased in breastfeeding patients compared to nonbreastfeeding patients. Doses of Loratadine for the treatment of dyslipidemias are greater than those used as a dietary supplement. Due to the potential for serious adverse reactions in the breastfed infant (including hepatoxicity), the manufacturer recommends that breastfeeding be discontinued when Loratadine is used for treatment of dyslipidemias.

There are no specific food warnings associated with the use of loratadine. However, taking loratadine with grapefruit juice may increase the levels of the drug in the bloodstream and increase the risk of side effects. Therefore, it is generally recommended to avoid consuming grapefruit or grapefruit juice while taking loratadine.

• Common Adverse effects:

Headache, Drowsiness or fatigue Dry mouth, Nausea, Stomach pain, Diarrhea, Increased appetite, Nervousness or agitation, Skin rash or itching.

• Less Common Adverse effects:

Cardiovascular effects such as increased heart rate, palpitations, and high blood pressure.

Respiratory effects such as thickening of bronchial secretions, which can make it difficult to breathe, especially in patients with asthma or COPD.

Skin reactions such as rash, hives, and itching.

Allergic reactions such as anaphylaxis, which is a severe and potentially life-threatening allergic reaction.

Gastrointestinal effects such as abdominal pain and diarrhea.

Fatigue, weakness, and headache.

• Rare Adverse effects

Allergic reactions: In rare cases, loratadine may cause an allergic reaction, which can be life-threatening. Symptoms of an allergic reaction may include difficulty breathing, swelling of the face, lips, tongue or throat, or a skin rash.

Liver injury: There have been rare reports of liver injury associated with the use of loratadine, including cases of hepatitis and elevated liver enzymes.

Seizures: Loratadine may lower the seizure threshold in some people, especially those with a history of seizures or epilepsy.

Cardiac events: There have been rare reports of cardiac events associated with the use of loratadine, including tachycardia, palpitations, and QT prolongation.

• Azole antifungals: Azole antifungal medications such as ketoconazole may also increase the levels of loratadine in the bloodstream, increasing the risk of side effects.
• Rifampicin and other strong CYP3A4 inducers: These medications may decrease the levels of Loratadine in the body, reducing its effectiveness.
• Cimetidine, a medication used to treat stomach ulcers, may increase the levels of loratadine in the bloodstream, increasing the risk of side effects.
• Rifampin, an antibiotic used to treat tuberculosis and other infections, may decrease the levels of loratadine in the bloodstream, decreasing its effectiveness.

The common side effects of Loratadine include the following :

Headache ,Dry mouth, Fatigue ,Nausea, Dizziness, Sleepiness ,Sore throat, Abdominal pain ,Diarrhea, Muscle pain.

The symptoms of Loratadine overdose are not well documented as overdose cases are rare. However, it is generally recommended to follow the prescribed dose of Loratadine, and in case of accidental overdose or intentional ingestion of a large amount of Loratadine, seek immediate medical attention.

Pharmacodynamic

Loratadine is a second-generation antihistamine that works by blocking the action of histamine, a substance produced by the body in response to allergens. Histamine causes the symptoms of allergy, such as sneezing, itching, and runny nose, by binding to histamine receptors in the body. Loratadine blocks the H1 histamine receptors in the body, preventing histamine from binding to them and reducing the allergic response.

Pharmacokinetics

• Absorption: Loratadine is rapidly absorbed after oral administration, with peak plasma concentrations reached within 1-2 hours. However, its absorption is reduced when taken with food or grapefruit juice.

• Distribution: Loratadine is extensively distributed throughout the body, including into breast milk. It is about 97% bound to plasma proteins, mainly albumin.

• Metabolism: Loratadine undergoes extensive hepatic metabolism to form its active metabolite, desloratadine, by the cytochrome P450 enzyme system, mainly CYP3A4 and CYP2D6. Desloratadine is responsible for most of the clinical effects of loratadine.

• Excretion: Loratadine and its metabolites are excreted primarily in the urine and feces. The elimination half-life of loratadine is approximately 8-14 hours, while that of desloratadine is 27 hours.

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1364710/
2. https://reference.medscape.com/drug/colestid-Loratadine -342452
3. https://go.drugbank.com/drugs/DB00375
4. https://www.sciencedirect.com/topics/medicine-and-dentistry/Loratadine
5. https://europepmc.org/article/med/6988203