[Edaily Reporter NA EUN-KYUNG ] During seasonal transitions, when the temperature difference between morning and evening widens, more people complain of sneezing, a clear runny nose, and itchy noses and eyes. While it’s easy to mistake these symptoms for a cold, if they recur at specific times or in specific places without a fever or body aches, it could be allergic rhinitis.

Allergic rhinitis occurs when the immune system overreacts to allergens such as pollen, dust mites, mold, and animal dander. When histamine released during this reaction binds to receptors in the nasal mucosa, symptoms such as sneezing, a runny nose, and itching appear. Antihistamines, commonly referred to as allergy medications, block the action of histamine to reduce these symptoms.

Common allergy medications readily available at pharmacies include “Zyrtec Tablets,” “Allershot Soft Capsules,” and “Allegra 120 mg Tablets.” Although all are second-generation antihistamines, they differ in active ingredients, dosage forms, the degree of drowsiness they cause, and dosage instructions.

Zyrtec Tablets by Korea UCB Pharmaceuticals and AllerShot Soft Capsules by GCGreen Cross Corporation(006280)both contain 10 mg of cetirizine hydrochloride. Mirae Pharmaceutical’s Notec tablets and Jeil Health Science’s Jeil Algi-Sseti soft capsules also contain the same active ingredient and dosage. Cetirizine is used to treat allergic rhinitis, conjunctivitis, hives, and itchy skin.

Adults and children aged 6 and older generally take 10 mg once daily before bedtime. Since drowsiness, fatigue, and dry mouth may occur depending on the individual, it is advisable to avoid driving or operating dangerous machinery after taking it for the first time. Drowsiness may be exacerbated if taken with substances that depress the central nervous system, such as alcohol or sleeping pills.

The most noticeable difference between Zyrtec and AllerShot is their dosage form. Zyrtec comes in tablet form, while AllerShot is a soft gel capsule. Since the active ingredient in soft capsules is already dissolved in a liquid, the disintegration process may be simpler than that of tablets. As the basic efficacy expected from a 10 mg cetirizine single-ingredient product is the same, if you do not have a particular preference for a specific formulation or brand, you can compare package sizes and prices to choose the relatively more affordable option.

HANDOK Inc.(002390)Allegra 120 mg tablets contain fexofenadine hydrochloride. Fexofenadine is known to cause relatively less drowsiness than cetirizine because less of it crosses the blood-brain barrier.

Allegra 120 mg tablets are taken once daily before a meal by adults and adolescents aged 12 and older. As a general rule, they should be taken with water rather than other beverages such as juice or coffee. In particular, grapefruit, orange, and apple juices can reduce the absorption of fexofenadine in the body, so it is best to avoid taking them together. Antacids containing aluminum or magnesium may also interfere with the absorption of fexofenadine. If you are taking heartburn medication or antacids, consult your pharmacist; generally, it is recommended to leave an interval of about 2 hours between doses.

There are also products containing loratadine. A representative product is Bayer Korea’s Claritin tablets, and Floradin soft capsules ( DongwhaPharm(000020)) and Lorashot soft capsules ( Aprogen Biologics(003060)) also contain 10 mg of loratadine. The difference is that Claritin comes in tablet form, while Floradin and Lorashot are soft capsules. Loratadine is also known to cause less drowsiness than cetirizine.

Adults generally take a 10 mg single-ingredient loratadine tablet once a day. Even though loratadine is known to cause relatively less drowsiness, individual responses vary, so you should monitor your body’s reaction after taking it for the first time.

In cases of severe nasal congestion accompanied by a runny nose, people may seek combination medications such as Actiphed tablets ( SamilPharmaceutical(000520)). Actiphed tablets contain the antihistamine triprolidine along with pseudoephedrine, which constricts blood vessels in the nasal mucosa. While these tablets can help relieve nasal congestion, they may cause drowsiness, palpitations, insomnia, and increased blood pressure. Therefore, people with high blood pressure, heart disease, thyroid disorders, glaucoma, or benign prostatic hyperplasia should consult a healthcare professional before taking them.

Taking two or more allergy medications with different active ingredients does not proportionally increase their effectiveness. Since many cold remedies also contain antihistamines, taking them alongside allergy medication can result in overlapping ingredients and may actually worsen side effects such as drowsiness or dry mouth.

While antihistamines are effective at reducing sneezing, a runny nose, and itching, they may not be sufficiently effective for nasal congestion. If symptoms persist or interfere with sleep and daily life, it is better to visit a healthcare provider to determine the exact cause rather than continuously switching medications. If symptoms are accompanied by yellow nasal discharge, fever, or facial pain, there is a possibility that another condition, such as an infection or sinusitis, is present.