Habitek (Cetirizine Dihydrochloride)

Habitek is indicated for the symptomatic treatment of several common allergic disorders.

• Relief of sneezing, nasal congestion, and itchy or watery eyes caused by seasonal or perennial allergic rhinitis.
• Management of itching, redness, and swelling associated with chronic or acute urticaria (hives).
• Alleviation of hay‑fever symptoms such as nasal discharge and throat irritation.
• Short‑term use for occasional allergic reactions triggered by environmental allergens.
• Supportive treatment of mild allergic conjunctivitis when eye irritation is present.
• Adjunct therapy for patients experiencing intermittent allergic skin reactions not requiring systemic steroids.

Like other second‑generation antihistamines, cetirizine may cause side effects, most of which are mild, dose‑related, and transient, and typically resolve without medical intervention.

Common

• Mild drowsiness or feeling of fatigue.
• Dry mouth or throat.
• Headache.
• Nausea or stomach discomfort.
• Transient dizziness.
• Mild insomnia.
• Temporary visual disturbances such as blurred vision.

Serious

• Signs of an allergic reaction such as rash, swelling, or difficulty breathing.
• Rapid or irregular heartbeat, especially in patients with pre‑existing cardiac conditions.
• Marked elevation of liver enzymes (rare).
• Severe skin reactions such as Stevens‑Johnson syndrome.
• Significant drop in blood pressure.
• Persistent vomiting or diarrhea leading to dehydration.

When using Habitek, certain precautions should be considered to ensure safe and effective use, especially in specific patient groups.

• Do not exceed the recommended daily dose; higher doses increase the risk of sedation.
• Caution in patients with impaired kidney function, as cetirizine is primarily excreted renally.
• Use with care in individuals with a history of cardiac arrhythmias.
• Avoid driving or operating machinery if you experience drowsiness.
• Pregnant or breastfeeding women should consult a healthcare professional before use.
• Elderly patients may be more sensitive to central nervous system effects.

Cetirizine can interact with other medicines; understanding which combinations to avoid or monitor helps maintain therapeutic benefit.

Avoid

• Alcohol, because it may increase drowsiness.
• First‑generation antihistamines, which can add to sedation and anticholinergic effects.
• Monoamine oxidase inhibitors (MAOIs), due to potential additive central nervous system effects.
• Ritonavir or other strong CYP3A4 inhibitors (though cetirizine is not heavily metabolized, caution advised).

Use with caution

• Sedating CNS depressants such as benzodiazepines or opioids.
• Theophylline, as cetirizine may slightly increase its plasma levels.
• Certain antifungal agents (e.g., ketoconazole) that affect hepatic metabolism.
• Antacids containing aluminum or magnesium, which may reduce absorption.
• St. John’s wort, a CYP inducer, may lower cetirizine levels.