How to choose the right allergy medication this spring

When allergic rhinitis becomes more severe, nasal steroid sprays, which are generally available by prescription, may offer better symptom control than oral antihistamines.

Jung Jae-hoon

The author is a pharmacist and food writer.

As this year’s pollen season arrived earlier than usual, many allergy sufferers are reaching for over-the-counter medications to manage symptoms. Among these, oral antihistamines are the most commonly used treatments for mild allergic rhinitis, offering relief from sneezing, runny nose, nasal and eye itchiness and watery eyes. However, their effectiveness in easing nasal congestion tends to be limited.

An oak tree with new leaf growth also shows pollen hanging amongst the branches at a park in Richardson, Texas, Thursday, March 21, 2024. [AP/YONHAP]

When selecting an antihistamine, health experts emphasize focusing less on efficacy and more on potential side effects. Antihistamines are generally classified into two groups: first generation and second generation. While both types are similarly effective in treating allergic rhinitis, they differ significantly in terms of side effects.

The primary distinction lies in how the drug interacts with the brain. First-generation antihistamines cross the blood-brain barrier, increasing the likelihood of drowsiness and sedation. These side effects can impair cognitive function, posing risks for students and individuals who drive or operate machinery. Some people may try to take first-generation antihistamines at night to help with sleep, while relying on second-generation options during the day. However, experts advise against this practice, as it can cause lingering drowsiness into the following day.

First-generation antihistamines may also dry out nasal passages and the mouth, sometimes excessively, by thickening mucus. This can lead to increased discomfort rather than relief. Long-term or frequent use of these medications has also been linked to a heightened risk of dementia, which is another reason second-generation antihistamines are generally recommended.

That said, not all second-generation antihistamines are completely free from sedative effects. For example, cetirizine may cause drowsiness in roughly one out of 10 users. Loratadine can also induce drowsiness when taken at higher doses, while fexofenadine typically does not produce such side effects, even at increased dosages. Even if a product is labeled as “non-drowsy,” individual reactions may vary, so caution is still advised.

For optimal results, oral antihistamines should be taken before exposure to allergens. Individuals who experience seasonal symptoms during high-pollen periods are encouraged to take these medications daily throughout the season. For those with milder symptoms, taking antihistamines as needed may be sufficient, given their relatively quick onset of action.

When allergic rhinitis becomes more severe, nasal steroid sprays, which are generally available by prescription, may offer better symptom control than oral antihistamines. These corticosteroid sprays need to be used consistently over a longer period to be effective.

There is currently no cure for allergic rhinitis. However, understanding how allergy medications work — along with their side effects — can help reduce symptoms and improve daily comfort.

Translated from the JoongAng Ilbo using generative AI and edited by Korea JoongAng Daily staff.