LEVOCETIRIZINE

What is levocetirizine?

Levocetirizine is an antihistamine medication that relieves allergy symptoms such as a runny nose, sneezing, redness, and itchiness of the eyes caused by hay fever and hives. The recommended dose is typically 5 mg once daily or 2.5 mg once daily for children ages six to 11. It is very similar to cetirizine in its chemical structure but may cause less drowsiness.

How can levocetirizine help alleviate certain long COVID symptoms? 

Histamine is a chemical our immune system releases that causes allergy symptoms. Cells in our body called mast cells release histamine, and in some patients, after COVID, they may release too much, leading to a prolonged inflammatory response.

Long COVID is believed to be caused by a persistent hyper-inflammatory state that results in symptoms such as fatigue, arthralgia, myalgia, shortness of breath, chest pain, and rash. Two types of drugs can block histamine in the body: H1- and H2-antihistamines. Levocetirizine is an H1-antihistamine that is believed to reduce the inflammatory effects associated with long COVID.

Montelukast, a leukotriene receptor antagonist commonly used for seasonal allergies and asthma, is believed to have a synergistic effect when combined with levocetirizine. Montelukast works by blocking substances in the body that cause inflammation and allergic diseases. The combination of levocetirizine can result in a more robust anti-inflammatory response.¹

What evidence supports levocetirizine’s use for long COVID?

While studies have shown improvement in long COVID symptoms with other antihistamine combinations, few studies have looked at the efficacy of levocetirizine alone for long COVID symptoms. For an active COVID infection, a study with 53 COVID patients ranging from mild to severe infection who were given levocetirizine 5 mg and montelukast 10 mg daily for 14 days in combination with standard care found that most patients experienced symptom resolution within seven days. In addition, no patients exhibited long COVID symptoms greater than three months.¹

Cetirizine has also been studied in hospitalized COVID patients and was found to reduce inpatient mortality and progression of pulmonary symptoms.² Levocetirizine may have similar effects based on their chemical similarity. More studies are needed to determine the benefit of long COVID.

What should you be aware of when taking levocetirizine?

Because it is less sedating and a newer drug on the market, levocetirizine can be more expensive than over-the-counter cetirizine. Both medications share very similar side effect profiles. Levocetirizine can cause fatigue, diarrhea, drowsiness, and constipation. For those with reduced kidney function, half (2.5 mg) of the typical dose is suggested.

References:

1)      May BC, Gallivan KH. Levocetirizine and montelukast in the COVID-19 treatment paradigm. Int Immunopharmacol. 2022 Feb;103:108412. doi: 10.1016/j.intimp.2021.108412

2)     Hogan RB, Cannon T, Rappai M, Studdard J, Paul D, Dooley TP. Dual-histamine receptor blockade with cetirizine – famotidine reduces pulmonary symptoms in COVID-19 patients. Pulm Pharmacol Ther. 2020 Aug;63:101942. doi: 10.1016/j.pupt.2020.101942