Clarinase (Antihistamine)

What is Clarinase?

Clarinase is a Pharmacy Only Medicine widely used to manage symptoms of hay fever and the common cold. It combines a non-drowsy antihistamine with a systemic nasal decongestant to provide dual-action relief from respiratory allergies.

Compared to single-ingredient antihistamines, this combination targets both allergic responses and sinus swelling. It works by blocking histamine receptors to stop allergy symptoms while simultaneously stimulating alpha-adrenergic receptors to constrict blood vessels in the nasal passages, clearing congestion.

Generic Names:

• Loratadine/pseudoephedrine: The standard chemical name for this combination medication used in medical literature globally.

Global Brand Names:

Clarinase is a widely recognized brand for this combination, though it is sold under various names internationally.

• Clarinase (佳利連絲): The primary brand available in Hong Kong pharmacies, offered in 12-hour Repetabs and 24-hour formulations.
• Claritin-D: The most famous brand name for this specific active ingredient combination in the United States and North America.

These names all refer to the same medication. It's important to note that while the active ingredient is the same, different countries may have different regulations and available medication formulations.

What is Clarinase used for?

Clarinase is used to relieve:

• Nasal and sinus congestion
• Sneezing
• Runny nose (rhinorrhea)
• Itchy and watery eyes

How do you use Clarinase?

Availability:

• Extended-release tablets (12-hour and 24-hour formulations)

Dosage Information:

• Adults and children 12 years and older: One tablet twice daily (12-hour formulation) or one tablet once daily (24-hour formulation).

Suitability:

• Adults: Yes.
• Elderly: Yes, but with caution due to increased sensitivity to decongestants.
• Children under 12: No, safety data is insufficient.

Who cannot take Clarinase?

Allergies and unsuitability:

• Rare, but possible allergic reactions to loratadine or pseudoephedrine.

Conditions where the drug should not be used:

• Active or recent use of Monoamine Oxidase Inhibitors (MAOIs)
• Severe hypertension (high blood pressure)
• Severe coronary artery disease
• Narrow-angle glaucoma
• Urinary retention
• Hyperthyroidism

Common side effects include insomnia, dry mouth, headache, dizziness, and mild fatigue. Because it contains a decongestant component, some users may also experience nervousness or a temporary increase in heart rate. Less common but more severe adverse effects related to pseudoephedrine include palpitations, cardiac arrhythmias, and increased blood pressure.

In rare cases, severe skin reactions or hypersensitivity reactions like rashes and swelling may occur. Exceeding the recommended dosage sharply increases the risk of cardiovascular complications and central nervous system overstimulation, requiring immediate medical attention.

• Avoid taking within 14 days of Monoamine Oxidase Inhibitor (MAOI) therapy to prevent a severe hypertensive crisis.
• Check with a doctor if you have hypertension, diabetes, or ischemic heart disease to reduce the risk of cardiovascular complications.
• Do not crush, chew, or break the tablets to prevent releasing the drug all at once and risking a dangerous overdose.
• Avoid using alongside other sympathomimetic decongestants or diet pills to prevent dangerous increases in blood pressure.

Storage information:

• Keep in a cool, dry place below 25°C or 30°C (refer to specific manufacturer packaging).
• Keep the medication in its original blister pack to protect it from moisture.
• Store securely out of the reach of children.

Handling instructions:

• Swallow the tablet whole with a full glass of water.
• Do not crush, chew, or break the sustained-release tablets before swallowing.

Where is Clarinase available in Hong Kong?

In Hong Kong, Clarinase is classified as a "Pharmacy Only Medicine". This means that while no doctor's prescription is needed, it must be purchased at a registered pharmacy under the direct supervision of a registered pharmacist.

You can legally obtain this medication at registered community pharmacies and dispensary counters within major chain drug stores (such as Mannings and Watsons) that clearly display the "Rx" logo.