Cetirizine vs Fexofenadine: How These Popular Antihistamines Compare for Allergy Relief

Allergic rhinitis is highly prevalent globally, with estimates indicating 10-30% of people worldwide are affected. Chronic urticaria is less common but still impacts around 1% of the general population. While chronic urticaria often resolves within 2-5 years, symptoms linger longer than 5 years in approximately 20% of patients.

Cetirizine and fexofenadine are two widely used second-generation antihistamines that can relieve the bothersome symptoms of these allergy disorders. As histamine receptor antagonists, they prevent histamine from binding to receptors, thereby blocking its effects in the body.

While both cetirizine and fexofenadine have demonstrated efficacy and safety for allergic conditions, there are some notable differences between these two medications. This article compares key factors healthcare providers and patients should consider when choosing between cetirizine vs. fexofenadine.

1. Mechanism of Action

Both cetirizine and fexofenadine work by blocking histamine receptors to prevent allergy symptoms, but their mechanisms have some key differences.

Cetirizine

Cetirizine belongs to the second generation of antihistamines, and its primary mechanism of action is to reduce the effects of histamine in the body.

Cetirizine selectively targets histamine receptors, preventing histamine from exerting its effects. By doing so, cetirizine effectively alleviates cold or allergy symptoms such as:

• Sneezing
• Itching
• Watery eyes
• Runny nose

It also addresses allergic reactions, itching, and swelling associated with chronic urticaria (hives). The drug is indicated for various allergic conditions, including:

• Perennial and seasonal allergic rhinitis
• Chronic idiopathic urticaria
• Allergic asthma
• Physical urticaria
• Atopic dermatitis

Cetirizine is a non-drowsy antihistamine, but it may cause drowsiness in some individuals, particularly at higher doses.

Fexofenadine

Fexofenadine is an antihistamine that works selectively on histamine-1 receptors in the body, excluding the central nervous system. These receptors, known as peripheral histamine receptors, are crucial in allergic responses.

By binding to these receptors, fexofenadine prevents histamine from exerting its effects, reducing allergy symptoms such as:

• Watery eyes
• Runny nose
• Sneezing
• Itching

Fexofenadine is mainly known for its low likelihood of causing drowsiness compared to some older antihistamines.

2. Dosage and Administration

When it comes to dosage and administration, cetirizine and fexofenadine have some similarities but also key differences depending on patient age and formulation.

Cetirizine

Cetirizine is commonly prescribed for allergic rhinitis and urticaria, with specific dosages for different age groups.

In adults, the usual dose for both conditions is 5 to 10 mg orally once daily, with a maximum daily dose of 10 mg.

Geriatric patients are advised to start with 5 mg orally once a day. Pediatric doses vary, with infants aged 6 months to 2 years starting at 2.5 mg orally once a day and older children ranging from 5 to 10 mg once daily.

The drug can be taken with or without food, and capsules should be consumed with a glass of water. Storage requirements include protecting the oral solution from light.

Caution is advised for patients with hypersensitivity to the active component or related antihistamines. Safety and efficacy have not been established for children under 6 months (prescription formulations) and 6 years (over-the-counter formulations).

Patients are cautioned about potential drowsiness and advised to avoid driving or operating machinery until the full effects of the drug are observed. Any allergic reactions should be promptly reported.

Fexofenadine

Fexofenadine is another antihistamine commonly used for allergic rhinitis and urticaria, with different dosages for adults and children.

The usual adult dose for both conditions is 180 mg orally once a day or 60 mg twice daily, with a maximum daily dose of 180 mg.

Pediatric doses vary by age, with infants aged 6 months to 2 years receiving 15 mg orally twice a day and those aged 2 to 11 years receiving 30 mg orally twice daily.

The oral suspension may be used in infants, tablets, and oral dissolving tablets in children aged 6 to 11 years, and gel-coated tablet formulations are limited to those 12 years and older.

Oral dissolving tablets should be taken on an empty stomach without chewing, and the oral suspension should be shaken well before administration. Patients should report any signs of an allergic reaction promptly.

3. Efficacy in Allergy Symptoms

The efficacy of cetirizine and fexofenadine in treating allergic rhinitis has been extensively studied, with various research articles providing insights into their effectiveness and safety.

A study comparing fexofenadine and cetirizine for allergic rhinitis treatment found that both antihistamines demonstrated similar efficacy and safety profiles. The study included 176 patients, and the two groups had no significant differences in effectiveness or safety parameters. The results confirmed the efficacy and safety of fexofenadine in treating allergic rhinitis, providing valuable information for clinicians and patients seeking relief from allergy symptoms.

Another study focused on the comparative efficacy of cetirizine and fexofenadine in treating chronic idiopathic urticaria (CIU). The research, involving 116 patients, concluded that cetirizine showed a therapeutic advantage over fexofenadine in treating CIU. The response to treatment, as judged by symptom-free status, partial improvement, or no improvement, favored cetirizine over fexofenadine. The study also reported mild side effects with no significant differences between the antihistamines.

Additionally, a study evaluating the 24-hour activity of cetirizine and fexofenadine in the skin demonstrated that cetirizine exhibited better duration of action and consistency in antihistaminic activity than fexofenadine. The study involved 26 healthy volunteers and found that cetirizine provided a longer duration of inhibition of histamine-induced skin reactivity compared to fexofenadine, with better consistency in activity. No serious adverse events were reported during the study.

In a randomized, double-blind, placebo-controlled study focusing on seasonal allergic rhinitis, cetirizine and fexofenadine were compared regarding their response to treatment between 5 and 12 hours postdose. The study involved 599 subjects exposed to ragweed pollen. Cetirizine demonstrated greater relief of symptoms than fexofenadine at 12 hours postdose and over the 5- to 12-hour postdose period. The results emphasized cetirizine's effectiveness in relieving seasonal allergic rhinitis symptoms during the specified time frame.

Overall, these studies collectively support the efficacy and safety of cetirizine and fexofenadine in treating allergic rhinitis and related conditions, providing valuable information for healthcare professionals and individuals seeking appropriate antihistamine treatment options.

4. Side Effects

When considering side effects, both Cetirizine and Fexofenadine are typically well tolerated but have potential safety profile differences.

Cetirizine

Serious side effects:

Incidence not known

• Drowsiness
• Relaxed and calm
• Sleepiness or unusual drowsiness

Other side effects:

Rare

• Acid or sour stomach
• Belching
• Burning, crawling, itching, numbness, prickling, "pins and needles," or tingling feelings
• Change or loss of taste
• Feeling hot
• Headache
• Heartburn
• Increased sweating
• Indigestion
• Stomach discomfort, upset, or pain

Incidence not known

• Bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site

Nervous system:

Very common

• Somnolence (up to 14.3%)
• Headache (up to 14%)

Common

• Dizziness

Frequency not reported

• Altered sense of taste, paresthesia, hypertonia, tremor, abnormal coordination/incoordination, ataxia, hyperesthesia, hyperkinesia, hypoesthesia, migraine, paralysis, twitching, parosmia, taste loss/perversion

Gastrointestinal:

Common

• Dry mouth, nausea, diarrhea, vomiting, abdominal pain

Uncommon

• Dyspepsia

Frequency not reported

• Tongue disorder, constipation, flatulence, increased salivation, aggravated tooth caries, eructation, gastritis, hemorrhoids, melena, rectal hemorrhage, stomatitis/ulcerative stomatitis, tongue discoloration/edema, enlarged abdomen

Fexofenadine

Serious side effects:

Rare

• Chest tightness
• Feeling of warmth, redness of the face, neck, arms, and occasionally, upper chest
• Large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
• Shortness of breath, difficult or labored breathing

Other side effects:

More common

• Vomiting

Less common

• Back pain
• Body aches or pain
• Chills
• Coughing
• Diarrhea
• Difficulty with moving
• Dizziness
• Ear congestion
• Earache
• Fever
• Headache
• Joint pain
• Loss of voice
• Muscle aching or cramping
• Muscle pains or stiffness
• Nasal congestion
• Nausea
• Pain in arms or legs
• Pain or tenderness around eyes or cheekbones
• Painful menstrual bleeding
• Redness or swelling in the ear
• Ringing or buzzing in ears
• Runny or stuffy nose
• Sleepiness or unusual drowsiness
• Sneezing
• Sore throat
• Stomach upset
• Swollen joints
• Unusual feeling of tiredness or weakness
• Viral infection (such as cold and flu)

Rare

• Nervousness
• Rash
• Sleeplessness
• Terrifying dreams
• Trouble sleeping

5. Cost

The costs of these two popular antihistamines are relatively comparable. Here’s a breakdown.

Cetirizine

The cost for a cetirizine oral tablet of 10 mg is approximately $11 for a supply of 30 tablets, depending on the pharmacy. Prices for other formulations, such as oral liquid and chewable tablets, vary.

For instance, the oral liquid is priced from $19.16 for 118 milliliters, and chewable tablets range from $39.13 to $49.88 for 30 tablets. Printable coupons and discount cards, like the Drugs.com Discount Card, can offer savings of up to 80% for cash-paying customers.

Fexofenadine

The cost for fexofenadine oral tablet 180 mg is around $10 for a supply of 5 tablets, with varying prices for other formulations such as oral suspension and 60 mg tablets.

For example, the oral suspension costs $17.47 for 118 milliliters. Printable coupons and discount cards, such as the Drugs.com Discount Card, can provide significant savings like cetirizine.

Wrap Up

Cetirizine and fexofenadine are both effective and commonly used second-generation antihistamines for treating allergy symptoms associated with conditions like allergic rhinitis and chronic idiopathic urticaria. While research shows comparable efficacy overall, some studies give cetirizine an advantage for urticaria and a longer duration of action.

Dosage and administration vary, with cetirizine being administered once or twice daily based on age, while fexofenadine is typically taken twice daily, although there is also an option for single-day dosing at 180mg. Side effects are generally mild, but cetirizine is more likely to cause drowsiness, while fexofenadine is less sedating.

In terms of cost, a 30-day supply of cetirizine 10mg tablets is approximately $11, comparable to $10 for 5 fexofenadine 180mg tablets. So while subtle differences exist in aspects like efficacy and side effect profiles, both provide affordable options for managing allergy symptoms.

FAQs on Cetirizine and Fexofenadine

How long does it take for cetirizine to work?

Cetirizine starts working within 1-3 hours with maximum effect seen after 3-6 weeks of daily use. The drowsiness side effect tends to decrease over time as the body adjusts.

Can cetirizine be taken long-term?

Yes, cetirizine is approved for long-term daily use. It is not addictive, but for safety reasons should not be taken in larger amounts or more often than prescribed.

Is there an over-the-counter version of cetirizine?

Yes, Zyrtec (cetirizine) is available over-the-counter without a prescription in 10 mg tablets for adults and syrup form for children over 2 years old. The dose and usage are the same.

How long does it take for fexofenadine to work?

Fexofenadine starts working within 1-3 hours, with maximum relief of symptoms within 12-24 hours. It works for a full 24 hours.