Cetirizine vs. Loratadine — What's the Difference?

Cetirizine, commonly known by the brand name Zyrtec, is an antihistamine that reduces the effects of natural histamine in the body. It's known for its quick onset, typically beginning to work within an hour of ingestion, which is beneficial for rapid relief of allergy symptoms such as sneezing, itching, watery eyes, and runny nose. On the other hand, loratadine, known as Claritin, also treats the same symptoms but may take longer to take effect, usually about one to three hours after intake.

One notable difference between cetirizine and loratadine is their sedative effects. Cetirizine is slightly more sedating than loratadine, making it more likely to cause drowsiness. This can be an advantage for those who need help sleeping due to symptoms, but a disadvantage for those who need to remain alert. Loratadine is generally considered non-sedating and is preferred by people who need to avoid drowsiness during the day.

In terms of duration of action, both cetirizine and loratadine are long-acting antihistamines, typically providing relief for 24 hours, allowing for once-daily dosing. This makes them convenient for daily use, compared to first-generation antihistamines, which often require multiple doses throughout the day.

When comparing efficacy, both drugs are similarly effective for allergic rhinitis and hives, but individual responses can vary. Some users find that cetirizine may be more effective for severe symptoms, while others prefer loratadine for its milder side effects profile.

Both medications are available over-the-counter (OTC) and are widely used. The choice between cetirizine and loratadine may often come down to personal preferences regarding speed of action and potential for drowsiness.