Loratadine: Uses, Dosage, Side Effects, and More
1. Drug Name
Generic Name: Loratadine
Brand Name(s):
- Pakistan: Clarityne
- India: Lorfast, Loridin
- United States: Claritin, Alavert
- United Kingdom: Clarityn
2. Pharmacological Class
Class: Antihistamine
Subclass: Second-generation H1 antagonist
3. Mechanism of Action
Loratadine works by selectively blocking peripheral histamine H1 receptors. This action helps to prevent the symptoms associated with allergic reactions, such as sneezing, runny nose, and itching, without causing significant drowsiness.
4. Indications
Primary Indications:
- Allergic rhinitis (hay fever)
- Chronic idiopathic urticaria (hives)
Off-label Uses:
- Allergic conjunctivitis
- Pruritus (itching) due to other causes
5. Dosage and Administration
Standard Dosage:
- Adults and children 6 years and older: 10 mg once daily.
- Children 2-5 years: 5 mg once daily.
Route of Administration: Oral (tablets, syrup, disintegrating tablets).
Special Populations:
- Pediatric: Dose adjustment required for children under 6 years.
- Geriatric: Use with caution, start at a lower dose.
6. Pharmacokinetics
Absorption: Rapidly absorbed after oral administration.
Distribution: Widely distributed in the body, highly bound to plasma proteins.
Metabolism: Extensively metabolized in the liver to active metabolite desloratadine.
Excretion: Excreted primarily in urine and feces.
Half-life: Approximately 8 hours (loratadine), 27 hours (desloratadine).
7. Contraindications
Loratadine is contraindicated in patients with a known hypersensitivity to loratadine or any of its components. Caution should be used in patients with severe hepatic impairment.
8. Warnings and Precautions
Use with caution in patients with hepatic impairment. Although loratadine is less sedating than first-generation antihistamines, patients should be advised to avoid engaging in activities requiring mental alertness until they know how the drug affects them.
9. Side Effects
Common Side Effects: Headache, drowsiness, fatigue, dry mouth.
Serious Side Effects: Severe allergic reactions, including rash, itching, swelling, and difficulty breathing.
10. Drug Interactions
Major Interactions: Ketoconazole, erythromycin, and cimetidine can increase loratadine levels.
Moderate Interactions: Other CNS depressants may enhance sedative effects.
Minor Interactions: Minimal interactions with food or other drugs.
11. Pregnancy and Lactation
Pregnancy Category: Category B - No proven risk in humans, but use only if clearly needed.
Breastfeeding Considerations: Loratadine is excreted in breast milk, use with caution. Consult your doctor before use.
12. Patient Counseling Information
Key Points for Patients:
- Take loratadine exactly as directed. Do not exceed the recommended dose.
- Avoid alcohol and other sedatives while taking loratadine.
- Inform your doctor about any other medications you are taking to avoid potential interactions.
Administration Tips:
- Take with or without food.
- If using disintegrating tablets, allow them to dissolve on the tongue without water.