Cetirizine dosage, forms, and strengths

Cetirizine is an over-the-counter (OTC) non-drowsy antihistamine used to relieve upper respiratory allergy and hay fever symptoms such as sneezing, runny nose, itchy or watery eyes, itchy nose, and itchy throat. People probably know cetirizine better as Zyrtec, its original brand name. Cetirizine is also effective at treating itchy skin due to hives (urticaria) at lower doses. Lower-dose cetirizine is sometimes packaged as “Hives Relief.” A prescription-only injection is sold as a generic or under the brand name Quzyttir. Cetirizine prescription eye drops, sold under the brand name Zerviate, are prescribed to relieve itchy eyes due to allergic conjunctivitis. As an antihistamine, cetirizine blocks the actions of chemicals called histamines that produce the symptoms of an allergic reaction when triggered by allergens. 

Cetirizine forms and strengths

Nonprescription cetirizine is taken orally as a capsule, tablet, chewable tablet, orally disintegrating tablet (ODT), or oral solution. Prescription cetirizine is administered as an oral solution, eye drops, or intravenous injection.

• Capsules: 10 milligrams (mg)

• Tablets: 5 mg, 10 mg

• Chewable tablets: 5 mg, 10 mg

• Orally disintegrating tablets: 10 mg

• Oral solution: 1 mg per milliliter (mL)

• Eye drops: 0.24% (2.4 mg of cetirizine)

• Intravenous injection: 10 mg/mL

Cetirizine dosage for adults

Cetirizine is a nonprescription drug used to treat upper respiratory allergy symptoms and hives in adults and children older than six. Prescription cetirizine eye drops are approved by the Food and Drug Administration (FDA) to treat itchy eyes due to allergic conjunctivitis.

Cetirizine dosage for upper respiratory allergies and hay fever

The most common use of OTC cetirizine is for occasional relief of allergies, seasonal allergies, and hay fever. Cetirizine relieves allergic rhinitis, sneezing, itchy eyes, watery eyes, and itchy nose and throat. Adults will typically take 10 mg per day by mouth. A doctor may suggest a lower dose for people with kidney disease, liver disease, or older than 65 years old. 

• Standard adult dosage for allergies or hay fever: 10 mg taken once daily by mouth as needed

• Maximum adult dosage for allergies or hay fever: 10 mg per day

Cetirizine dosage for hives

Cetirizine hydrochloride Hives Relief products come in 5 mg doses, usually tablets or chewable tablets. The recommended dose is 5 mg, but people can take two 5 mg tablets if necessary. Cetirizine relieves the itching associated with hives but will not prevent hives or an allergic reaction.

• Standard adult dosage for hives: 5–10 mg taken once daily by mouth as needed

• Maximum adult dosage for hives: 10 mg per day

Cetirizine dosage for allergic conjunctivitis

Cetirizine eye drops can only be purchased with a prescription. The drops are used to relieve eye itching caused by allergic conjunctivitis.

• Standard adult dosage for allergic conjunctivitis: One drop (2.4 mg cetirizine) placed in each affected eye twice daily and administered eight hours apart

• Maximum adult dosage for allergic conjunctivitis: Two drops (4.8 mg cetirizine) per day

Cetirizine dosage for children

Children as young as six can take over-the-counter cetirizine at standard adult doses. Although oral cetirizine is FDA-approved for children younger than six, caregivers should first talk to a pediatrician or other healthcare professional. Prescription cetirizine oral solution is the most appropriate medication for children between six months and five years to treat allergy symptoms and chronic hives. Cetirizine eye drops can be prescribed to children as young as two. The FDA has approved cetirizine injections for children as young as six months old. 

Cetirizine children’s dosage for hayfever

• Standard pediatric dosage for allergies or hay fever in children six to 11 months old: 2.5 mg taken once daily by mouth as needed

• Standard pediatric dosage for allergies or hay fever in children 12 to 23 months old: 2.5-5 mg taken once daily by mouth as needed

• Standard pediatric dosage for allergies or hay fever in children two to five years old: 2.5-5 mg taken once daily by mouth as needed

• Standard pediatric dosage for allergies or hay fever in children and adolescents six years or older: 5-10 mg taken once daily by mouth as needed

Cetirizine children’s dosage for hives

• Standard pediatric dosage for hives in children six months to five years of age: 2.5 mg taken once daily by mouth or as an IV injection 

• Standard pediatric dosage for hives in children six to 11 years of age: 5–10 mg taken once daily by mouth or as an IV injection 

• Standard pediatric dosage for hives in adolescents 12 years of age and older: 5–10 mg taken once daily by mouth or 10 mg administered once daily as an IV injection 

Cetirizine children’s dosage for allergic conjunctivitis

• Standard pediatric dosage for allergic conjunctivitis in children between 2 and 17 years of age: One drop (2.4 mg cetirizine) placed in each affected eye twice daily and administered eight hours apart

Cetirizine dosage restrictions

Although the FDA has not mandated dosage restrictions or reductions, adults with renal impairment, hepatic impairment or who are older than 65 should talk to a healthcare provider before taking cetirizine. It’s recommended that these people take lower doses, usually 5 mg per day rather than 10 mg per day. Children younger than six years old with liver or kidney problems should not take cetirizine. Cetirizine should also never be taken by people who have had allergic reactions to the drug or to a similar antihistamine called hydroxyzine. 

Cetirizine dosage for pets

According to Plumb’s Veterinary Manual, veterinarians may use cetirizine to treat itching (pruritus) in dogs or cats due to hives, atopic dermatitis, or insect bites. It has also been used to treat inflamed nasal and sinus passages in cats. Dosages haven’t been standardized, but the Merck Veterinary Manual suggests the following dosages:

• Standard cetirizine dosage for dogs: 1 mg/kg or 10–20 mg per dog given by mouth as a tablet or syrup every 12 to 24 hours as needed

• Standard cetirizine dosage for cats: 1 mg/kg or 5 mg per cat given by mouth as a tablet or syrup every 12 to 24 hours as needed

How to take cetirizine

Nonprescription cetirizine is relatively uncomplicated to take. Simply take a tablet or capsule once per day if needed. Oral cetirizine can be taken with or without food. Eye drops are a bit more complex to get right. Always take this medicine as directed on the package label, package insert, or as instructed by a doctor. Cetirizine should be stored at room temperature and out of the reach of children and pets.

Tablets and capsules

• Swallow the tablet or capsule whole with a full glass of water. Do not chew, crush, or break it.

• Chewable tablets can be taken with or without water. Chew the chewable tablet thoroughly before you swallow it. You may also let the chewable tablet melt slowly in your mouth.

• Orally dissolving tablets can be taken with or without water. Allow the tablet to dissolve in the mouth fully.

Oral solution or syrup

• Measure the liquid medicine with a marked measuring spoon, oral syringe, or medicine cup. A measuring device should come with the medicine. If you don’t have one, ask the pharmacist.

Eye drops

• Wash your hands before administering the drops.

• Take out any contact lenses before administering cetirizine eye drops.

• To avoid infection, do not touch the tip of the bottle to the eye or eyelid.

• If using single-use containers, use them immediately after removing them from the foil wrapping.

• The single-use containers can be used to dose both eyes.

• When applying drops, pull down on the lower eyelid and put the drop in the pocket between the eye and the eyelid. 

• Discard the single-use containers after dosing the eyes. Do not save for later use even if there’s medicine left over.

• Store the single-use containers in the original foil wrapping.

Intravenous injections

• Cetirizine injections are only administered by a healthcare professional.

• Sleepiness is a common side effect of cetirizine injections. Be cautious about driving after an injection.

Cetirizine dosage FAQs

How long does it take cetirizine to work?

Cetirizine is fast-acting. People should start feeling relief of symptoms in 20 to 60 minutes. Cetirizine reaches its peak concentrations in the bloodstream about one hour after being taken.

How long does cetirizine stay in your system?

The effects of cetirizine last for at least 24 hours. With a half-life of about eight hours, it will take almost two days for a dose of cetirizine to be eliminated from the body.

What happens if I miss a dose of cetirizine?

Over-the-counter cetirizine is rarely taken on a schedule but instead taken as needed. Don’t take more than one dose a day. If a dose is missed, take it when remembered as long as it’s the only dose taken that day.

Cetirizine eye drops should be taken twice per day, eight hours apart. If a dose is forgotten, take it when remembered unless it’s almost time for the next dose. If that’s the case, take the missed dose, but do not take a second dose that day. If it’s not almost time for the next dose, take the missed dose, but then take the next dose eight hours later. Do not use extra medicine or take extra doses to compensate for a missed dose.

How do I stop taking cetirizine?

Cetirizine can be stopped at any time without causing withdrawal symptoms. 

People should stop taking cetirizine if they are allergic to the drug. If cetirizine is discontinued, people can take other over-the-counter and prescription antihistamines such as Benadryl (diphenhydramine) and Claritin (loratadine). People taking cetirizine eye drops can choose from several over-the-counter antihistamine eye drops. Most contain the antihistamine ketotifen as their active ingredient.

Can you overdose on cetirizine?

Too much cetirizine typically causes sleepiness in adults. Signs that a young child has overdosed on cetirizine include restlessness and irritability, drowsiness, and sleepiness. If too much cetirizine is taken or a child gets into this medicine, call a poison helpline or get immediate medical attention. 

What interacts with cetirizine?

Cetirizine should not be taken with the Monoamine Oxidase Inhibitor (MAOI) isocarboxazid (Marplan). Combining cetirizine with other drugs that slow down the brain will worsen the sedative effects of cetirizine. These include alcohol, opioids, barbiturates, sleeping aids, benzodiazepines, and other antihistamines.

Is it safe to take cetirizine during pregnancy?

The effects of cetirizine on women who are pregnant have not been studied. However, animal studies have shown no risks to the fetus or the pregnancy. Pregnant women should get medical advice from a doctor before taking cetirizine.

Is it safe to take cetirizine while breastfeeding?

The FDA does not recommend the use of cetirizine in women who are breastfeeding. Animal studies indicate that cetirizine is present in breast milk. Large doses or continued use may interfere with lactation or make the nursing infant drowsy.

What are the side effects of cetirizine?

As an OTC drug, cetirizine does not commonly cause adverse effects. The most common side effect is drowsiness. Other common side effects include abdominal pain, fatigue, and dry mouth. The most serious side effects are allergic reactions to the drug, including anaphylaxis

Sources

• Cetirizine, Drugs and Lactation Database

• Cetirizine, StatPearls

• Cetirizine drug summary, Prescriber’s Digital Reference

• Cetirizine hydrochloride capsules drug information, NIH National Library of Medicine

• Cetirizine hydrochloride (Hives Relief) tablets drug information, NIH National Library of Medicine

• Cetirizine hydrochloride oral solution drug information, NIH National Library of Medicine

• Cetirizine hydrochloride oral solution prescribing information, NIH National Library of Medicine

• Cetirizine tablets drug information, NIH National Library of Medicine

• Children’s Zyrtec Allergy cetirizine hydrochloride syrup drug information, NIH National Library of Medicine

• Children’s Zyrtec Allergy cetirizine hydrochloride tablet, orally disintegrating drug information, NIH National Library of Medicine

• Quzyttir prescribing information, NIH National Library of Medicine

• Zerviate prescribing information, NIH National Library of Medicine