Cetirizine (ZYRTEC®) Available Over-the-Counter

Emily M. Ambizas, Pharm.D., CDM

More than 50 million Americans suffer from allergic disease. It is the sixth most common chronic disease in the United States. Allergic rhinitis (AR) affects approximately 40 million people, up to 30% of adults and 40% of children.^1-2 Although there is no cure for this condition, treatment modalities are aimed at controlling the symptoms of AR, including sneezing, rhinorrhea, pruritus, and nasal congestion.

Unlike many other diseases, AR is not life-threatening; however, it can greatly affect a person's quality of life, disrupting daily functioning and sleep.³ As an increasing number of patients become more actively engaged in their health care needs, they will more likely self-diagnose and treat their allergic rhinitis when presenting to their pharmacist. This provides opportunities for pharmacists to have a greater impact on patient care. When managing AR, there are three major areas of focus: environmental control, pharmacotherapy, and immunotherapy.² Recognizing the role of pharmacists in assisting with the management of AR, an evidence-based pharmacotherapy guideline has been developed by Allergic Rhinitis and its Impact on Asthma (ARIA) in conjunction with the World Health Organization (WHO) entitled "Management of Allergic Rhinitis Symptoms in the Pharmacy".⁴

Pharmacists should first assess the patient's presenting history and symptoms, determining whether self management or referral to a physician is appropriate. When selecting an appropriate medication regimen, the pharmacist must consider efficacy, safety, and cost. Categories of medications available without a prescription includes antihistamines, decongestants, mast-cell stabilizers, and combination products, which help to relieve the symptoms of AR.

Until 2002, the only antihistamines available without a prescription were the first generation antihistamines, brompheniramine, chlorpheniramine, dimenhydrinate, diphenhydramine, and doxylamine, which are associated with high rates of sedation as well as anticholinergic adverse effects. In addition, these agents commonly require frequent dosing, 3-4 times daily, making adherence difficult. In November 2002, the FDA approved the Rx-to-OTC Switch of loratadine (Claritin®), the first second-generation antihistamine available without a prescription. The second-generation antihistamines, when compared to their predecessors, are associated with much lower rates of sedation, often being referred to as the non-sedating antihistamines. The ARIA guidelines recommend the use of these agents over the older agents due to their lower incidence of adverse effects.⁴

Pharmacists and allergy sufferers now have another second generation agent to recommend or choose without the need of a prescription – cetirizine (ZYRTEC®). The FDA has approved all forms of certirizine to be available behind the counter or over-the-counter.⁵ It is indicated for the temporary relief of symptoms due to hay fever or other respiratory allergies such as runny nose, sneezing, itchy, watery eyes, itchy throat or nose in persons 2 years of age and older. Cetirizine HCl 5 mg/pseudoephedrine HCl 120 mg (ZYRTEC-D®), in addition to the above indications, is also approved to relieve nasal congestion and pressure, as well as reducing swelling of the nasal passages and restoring freer breathing through the nose in adults and children 12 years and older. Cetirizine also carries the indication for relief of itching due to hives in persons 6 years of age and older. Cetirizine chewable tablets and tablets are approved for adults and children six years of age and older. The syrup is approved for adults and children 2 years of age and older.⁵

When deciding which agent to recommend to a patient, numerous factors must be considered. Although both loratadine and cetirizine have been shown to be efficacious in relieving the symptoms of allergic rhinitis, cetirizine appears to be superior over loratadine when compared in head-to-head studies. In these studies, cetirizine demonstrated a quicker onset of action and greater improvement in symptom scores when compared to loratadine.^6-9 Both agents are well tolerated, although cetirizine is associated with a risk of sedation at recommended doses. Cetirizine may be considered a mildly sedating antihistamine when compared to other second generation agents. It has been shown that somnolence related to cetirizine use is dose related, occurring in 6% of subjects receiving placebo, 11% of subjects receiving cetirizine 5 mg and in 14% of patients receiving cetirizine 10 mg.⁶ When compared to loratadine, somnolence is more prevalent; however, subjects did not discontinue treatment because of this effect.^6-9

Cetirizine was to be marketed as two distinct products for each dosage form. One product carries the indication and directions for treating symptoms of hay fever and other respiratory allergies. The second product carries the indication and directions for the relief of itching due to hives.⁵ However, at the time of this writing, ZYRTEC® syrup is the only dosage form to be marketed as two distinct products: Children's Zyrtec Allergy Syrup and Children’'s ZYRTEC® Hives Relief Syrup.

The cost of cetirizine for over-the-counter sales is approximately $20 for a one month supply.¹⁰ Although this switch may affect how insurers treat other second-generation antihistamines (increasing co-payments and requiring prior authorizations), one hopes it will be cost-effective for the patient despite this barrier. Since loratadine switched to non-prescription status, it has been shown to be cost-effective for patients, insurers and society.¹¹

References

1. American Academy of Allergy, Asthma and Immunology. Allergic Disorders: Promoting Best Practices. http://www.theallergyreport.com/reportindex.html Accessed: December 10, 2007
2. Berger WE. Overview of allergic rhinitis. Ann Allergy Asthma Immunol. 2003;90(Suppl 3): 7-12.
3. Schatz M. A survey of the burden of allergic rhinitis in the USA. Allergy. 2007: 62 (Suppl 85): 9-16.
4. Management of Allergic Rhinitis Symptoms in the Pharmacy. Allergic Rhinitis and Its Impact on Asthma (ARIA). Available at: http://www.whiar.org. Accessed: December 18, 2007.
5. FDA. FDA Approves Zyrtec for Nonprescription Use in Adults and Children. http://www.fda.gov/bbs/topics/NEWS/2007/NEW01750.html Accessed: December 10, 2007
6. Day JH, Briscoe M, Rafeiro E, et al. Comparative onset of action and symptom relief with cetirizine, loratadine, or placebo in an environmental exposure unit in subjects with season allergic rhinitis: confirmation of a test system. Ann Allergy Asthma Immunol. 2001; 87:474-81.
7. Meltzer EO, Weiler JM, Widlitz MD. Comparative outdoor study of the efficacy, onset and duration of action, safety of cetirizine, loratadine, and placebo for seasonal allergic rhinitis. J Allergy Clin Immunol. 1996;97:617-26.
8. Day JH, Briscoe MP, Clark RH, et al. Onset of action and efficacy of terfenadine, astemizole, cetirizine, and loratadine for the relief of symptoms of allergic rhinitis. Ann Allergy Asthma Immunol. 1997;79:163-72.
9. Day JH, Briscoe M, Widlitz MD. Cetirizine, loratadine, or placebo in subjects with seasonal allergic rhinitis: Effects after controlled ragweed pollen challenge in an environmental exposure unit. J Allergy Clin Immunol. 1998;101:638-45.
10. Available at www.drugstore.com. Accessed on August 25, 2008.
11. Sullivan PW. Switching prescription drugs to over the counter: consumers may benefit financially in examples from the US. BMJ. 2005;330(7496):904-5.