Allergy Relief

Key takeaways

• Allergy medicines split into two groups: antihistamine tablets that block histamine throughout the body, and nasal sprays that act locally on nasal tissue.
• The main tablet names are fexofenadine, levocetirizine, desloratadine and bilastine (nonsedating), plus older, sedating options like promethazine, hydroxyzine and cyproheptadine.
• The practical difference is sedation and speed: nonsedating tablets suit daytime use, while older antihistamines cause drowsiness but often work faster for sudden hives.
• Decongestant nasal sprays like oxymetazoline should not be used for more than a few days in a row: longer use causes rebound congestion that is worse than the original blockage.

How allergy medicines work

Antihistamines block the H1 receptor that histamine uses to trigger sneezing, itching, and swelling once your immune system reacts to a trigger like pollen or dust. Nasal corticosteroid sprays reduce inflammation directly in the nasal lining, which takes days of regular use to build to full effect. Decongestant sprays narrow blood vessels in the nose to open the airway quickly, but the effect is short and reverses with overuse.

Choosing between fexofenadine, fluticasone, azelastine, oxymetazoline, promethazine, hydroxyzine and cyproheptadine

• Fexofenadine is a nonsedating, once-daily antihistamine well suited to hay fever. Taking it with fruit juice can reduce how much the body absorbs, so water is the better choice.
• Fluticasone and budesonide are nasal corticosteroid sprays that reduce inflammation in the nose. They need daily use for several days before congestion improves, not just use during a flare.
• Azelastine is an antihistamine nasal spray that acts faster than a steroid spray, often within 15 to 30 minutes, though it can leave a bitter taste.
• Oxymetazoline is a decongestant spray that opens blocked nasal passages within minutes, but using it beyond 3 days in a row causes rebound congestion (rhinitis medicamentosa) that keeps you reaching for the bottle.
• Promethazine is an older, strongly sedating antihistamine used for severe itching or allergic reactions. It must not be given to children under 2 years old, since it can cause severe breathing depression at that age.
• Hydroxyzine is another older antihistamine used for hives and itching. It causes marked drowsiness, so it's often taken at night.
• Cyproheptadine treats hives and chronic itching and, as a side effect, tends to increase appetite.

Levocetirizine, desloratadine and bilastine are other nonsedating, once-daily antihistamines; the choice between them usually comes down to cost or personal response rather than a meaningful difference in effect.

Common questions

Which antihistamine won't make me drowsy?

Fexofenadine, levocetirizine, desloratadine and bilastine are all nonsedating at normal doses, unlike promethazine, hydroxyzine or cyproheptadine, which commonly cause sleepiness.

Can I use a decongestant spray every day?

No. Using oxymetazoline or a similar spray for more than a few days in a row triggers rebound congestion, where your nose gets more blocked once the spray wears off. A nasal steroid spray like fluticasone is the better choice for ongoing congestion.

Safety essentials

• Never give promethazine to a child under 2 years old: it carries a risk of severe respiratory depression at that age.
• Limit decongestant nasal sprays like oxymetazoline to a few days at a time to avoid rebound congestion.
• Sedating antihistamines (promethazine, hydroxyzine, cyproheptadine) affect alertness, so take care before driving or operating machinery.
• Seek urgent care for swelling of the face, lips, or throat, or difficulty breathing: these can signal a severe allergic reaction that antihistamines alone do not treat.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.