Side effects of stopping zyrtec


What are antihistamines?

Antihistamines are medicines that help stop allergy symptoms. These symptoms include:

  • itchy eyes
  • sneezing
  • runny nose or congestion
  • skin rashes such as hives.

They are normally taken by mouth. They come in tablets, capsules, chewable tablets, and liquids. Many people buy them over the counter (OTC) at a store. You can also get them through a prescription from your doctor.

Antihistamines are generally considered safe for most people. This includes adults, children over the age of 2, and older people. If you are pregnant or breastfeeding, ask your doctor if antihistamines are safe for you. Ask your doctor if you can take antihistamines if you have a chronic disease or condition. This includes heart disease, diabetes, or high blood pressure.

Path to improved health

You can take antihistamines different ways, depending on your symptoms. Some people take them only when they have symptoms. Others experience symptoms every day, so they take the antihistamine every day. Sometimes people take them before they are going to be exposed to something they are allergic to. This could include an animal (such as cats or dogs) or certain kinds of plants or flowers.

There are many different brands of antihistamines that you can buy over the counter. Some work in different ways. For example, some are designed to work for 4 to 6 hours. Others last for 12 to 24 hours. Make sure you read the label carefully. Follow the directions for how often to take the antihistamine.

Ask your doctor which OTC antihistamine is best for you based on your symptoms.

Why did my doctor give me a prescription when I could buy an over-the-counter antihistamine?

Compared to OTC medicines, prescription antihistamines are less likely to have side effects. These can include drowsiness, dry mouth, or blurry vision. They may be better for some people, including:

  • Older people.
  • Children during school hours.
  • People who work with machinery or drive cars.

Things to consider

Like most medicines, antihistamines can cause side effects. The most common include:

  • drowsiness
  • dizziness
  • dry mouth
  • blurry vision
  • decreased appetite
  • feeling nervous, irritable, or excited.

Some types of antihistamines can cause sleepiness. Do not drink alcohol when taking antihistamines.

Can I take my prescription antihistamine with other medicines?

You shouldn’t take prescription antihistamines if you also are taking certain other prescription medicines. These include erythromycin (an antibiotic) or certain medicines used to treat fungal infections. These include itraconazole or ketoconazole. When your doctor gives you a prescription, always ask if it’s safe to use with the other medicines you’re taking. Your pharmacist can also tell you what is safe to take. If you aren’t sure, ask the pharmacist or your doctor before taking another medicine.

Can I share my prescription antihistamines with friends who have allergies?

No. You should never share a prescription medicine with another person. Your doctor has examined you and has picked a medicine that is right only for your problem. Some antihistamines can cause serious side effects if they are given to people who are taking another medicine, or who should not take antihistamines for another reason.

Questions to ask your doctor

  • Do I need an antihistamine?
  • Can I take one over the counter, or do I need a prescription?
  • Which over-the-counter type of antihistamine is the best for my symptoms?
  • What are the side effects of this type or brand?
  • Is there anything I should avoid doing while I’m taking an antihistamine?
  • How long should I take it?

The short answer? Yes, you can take both Zyrtec and Benadryl. However, when it comes to treating sneezing, coughing, and watery eyes, it’s important to understand the side effects of OTC medications and what’s really going on with your body in the first place, says Kara Wada, M.D., assistant professor of allergy and immunology at Ohio State University Wexner Medical Center in Columbus.

So before you go too far down the road of self-treatment, visit a board-certified allergist/immunology doctor to confirm that your symptoms are indeed due to allergies (for a quick take, try our quiz). Then you and your doctor can come up with a comprehensive approach to symptom prevention and management, says Dr. Wada.

Back to the meds at hand: “While you can double up on Zyrtec and Benadryl, there is an increased risk of side effects, especially sedation, when you use both. Plus, taking two medications likely signals the need for better strategies,” Dr. Wada says. Clearly, these two allergy pills aren’t doing the trick for you.

Here’s how they work: Zyrtec is a long-acting antihistamine that’s taken once a day. Benadryl is a short-acting (about 4-to-6 hours max) one that may provide some additional relief. However, Benadryl often causes drowsiness and/or the jitters (yes, opposite reactions), so it’s not a great choice if you have to work, drive, or operate machinery.

When patients need additional allergy control, “I tend to recommend using a second long-acting allergy medication in the same class as Zyrtec, such as Claritin and Allegra. They both have a greater potential to last longer and are going to cause fewer side effects than Benadryl,” she says.

Dr. Wada suggests taking Zyrtec in the morning without food and a second same-class drug in the evening on especially uncomfortable days when allergy symptoms are flaring. However, she does caution that if someone needs to double up on OTC medications to get relief, it’s best to see a doctor. There may be other types of medications that can target your symptoms better.

For instance, a steroid nasal spray such as Flonase, Nasocort, or Rhinocort may be more effective in controlling nasal allergies than an oral medication alone, says Susan Besser, M.D., a family internist at Mercy Medical Center in Baltimore. “For itchy watery eyes, try an eye drop such as Naphcon A or Zaditor,” suggests Dr. Besser.

For severe allergies, shots are an option but they take a few years to work (you have to build immunity), so you’ll need symptom relief in the meantime.

Bottom line? When it comes to finding the best allergy medication for your needs, Dr. Wada says it usually requires a fair amount of trial and error. About 1 in 10 people will experience sedation with Zyrtec, so other drugs might be a better fit. What works great for you, may not for your friend. And taking them consistently is key: It can take two-to-four weeks of regular use to see their full effect. And remember: Always consult your doctor before starting a new OTC medication regime.

I Got Off Zyrtec and Flonase After 3o Years and My Vertigo is 100% Better


  • Jean Wolf and Dr. Patrick Baker

    I started coming to Baker Chiropractic and Wellness a little more than two years ago. I was experiencing pain with head movement of any kind. I had also been having periods of vertigo over the previous few years.

    After speaking with my regular doctor about the neck pain and if there was a connection between it and the vertigo, I was not satisfied with her solution of taking medications. That is when I decided to give chiropractic care a try. I was nervous about having someone work with my neck, but something needed to be done about the pain.

    Treatment started with an exam and X-ray. I was actually listened to as I explained what was happening with my neck. It was so refreshing to talk with someone who cared and understood. The X-rays showed the curve in my neck was basically non-existent. He promised that chiropractic treatments could help me. Over the past two years, it really has.

    The chiropractic adjustments and treatments started bringing relief to my pain right away. These were combined with recommended home exercises which I still do twice a day. Each follow-up X-ray showed improvement in the curvature of my neck. I was experiencing more neck motion with less pain.

    Since starting chiropractic care, there have been no new episodes of vertigo. If I am feeling any change in ear pressure, I let them know at adjustment time. It really helps. I used to experience an average of three headaches a month. Since starting treatment, I have only had a few headaches in the last two years.

    An unexpected benefit of chiropractic care has been a huge improvement in my allergies. After moving to Ohio 30 years ago, I started having really bad allergies every spring and fall. It was so bad that I had to use a prescription antihistamine like Zyrtek and Flonase nasal spray. Often I would develop a sinus or ear infection as well. The medications were able to stop the allergy symptoms, but they left me feeling tired all the time. I have not had to take a single antihistamine or use nasal spray in the last two years! I would not say my allergies have completely disappeared, but they have decreased to the point where I can actually live without medication except an occasional decongestant. I have not had any sinus or ear infections either. I no longer have to dread months of feeling like I am living in a medicine fog.

    The quality of my life has improved so much since coming to Baker Chiropractic and Wellness. No matter how I am feeling each time I go, I always leave feeling better. I encourage anyone who is suffering to give them a try. I highly recommend them!*

    Jean Wolf

    *Please note, there is no guarantee of specific results with our care and results may vary. Please contact us to discuss your specific condition.


    Generic Name: Cetirizine Hydrochloride

    Drug Class:

    Table of Contents

    • Overview
    • How to Take It
    • Side Effects
    • Warnings & Precautions
    • Drug Interactions
    • Dosage & Missing a Dose
    • Storage
    • Pregnancy or Nursing
    • More Information


    Zyrtec (Cetirizine Hydrochloride) is an antihistamine used to relieve hay fever and seasonal allergy symptoms, including runny nose; sneezing; and red, itchy, tearing eyes. It also may be used to treat itching and hives that result from certain skin conditions.

    It works by blocking histamine that your body makes during an allergic reaction.

    This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

    This information is for educational purposes only. Not every known side effect, adverse effect, or drug interaction is in this database. If you have questions about your medicines, talk to your health care provider.

    How to Take It

    Follow the directions for using this medicine provided by your doctor. It usually is taken once a day.

    Side Effects

    Side effects that may occur while taking this medicine include:

    • dry mouth, nose and throat
    • insomnia
    • drowsiness
    • upset stomach
    • diarrhea
    • headache
    • dizziness

    Contact your doctor immediately if you experience:

    • difficulty urinating
    • nervousness
    • anxiety
    • difficulty breathing
    • shaking or tremors
    • difficulty swallowing
    • restlessness
    • seizures
    • irregular or unusually fast heartbeat

    Warnings & Precautions

    • Talk to your doctor if you are allergic to Hydroxyzine or Levocetirizine; or if you have any other allergies.
    • DO NOT use this medication if you are allergic to Cetirizine.
    • Get medical help right away if you experience seizures.
    • This medicine may impair your reactions and thinking. Use caution if you are performing any activities that require you to be alert.
    • Alcoholic beverages can increase the effects of this medicine and should be avoided.
    • Get for medical help immediately if you experience breathing difficulties, rash, swelling or itching on the tongue, face, or throat), or severe dizziness.
    • Contact your doctor immediately if symptoms do not improve or if they get worse. If you have a fever, call your doctor right away.
    • For an overdose, seek medical attention immediately. For non emergencies, contact your local or regional poison control center at 1-800-222-1222.

    Drug Interactions

    Before taking any new medicine, either prescription or over-the-counter, check with your doctor or pharmacist. This includes supplements and herbal products.

    Dosage & Missed Dose

    Zyrtec should be taken once daily. It comes in 5 mg and 10 mg tablets, 1 mg/ml syrup, and 5 mg and 10 mg chewable tablets, which may be taken with water.

    Take your next dose as soon as you remember. If it is time for your next dose, skip the missed dose and go back to your regular schedule. Do not double doses or take extra medicine to make up for the missed dose.


    Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (preferably not in the bathroom). Throw away any medication that is outdated or no longer needed.


    If you plan on becoming pregnant, discuss with your doctor the benefits and risks of using this medicine during pregnancy. Tell your doctor if you are pregnant or plan to become pregnant while taking this medication. Cetirizine can pass into breast milk and may harm a nursing baby. Do not use Zyrtec while breast feeding without first consulting with your doctor.

    More Information

    For more information, talk to your doctor, pharmacist or health care provider, or you can visit this website, for additional information from the manufacturer of this drug.


    How Is Drug-Induced Hair Loss Treated?

    It’s important to review any medications you take, and discuss their potential side effects with your doctor and pharmacist. When hair loss does occur from a drug you’re taking, there is a good chance that the hair will grow back on its own after you stop taking the medication. If stopping the drug does not improve hair thinning, you may need to be treated with finasteride (Propecia) or minoxidil (Rogaine), medications that slow hair loss and can stimulate new hair growth.

    One technique may help prevent hair loss during chemotherapy. It’s called scalp hypothermia, and it involves placing ice packs on the scalp a few minutes before — and for about a half-hour after — chemotherapy treatment. Cooling the scalp reduces blood flow to the hair follicles, making it harder for the chemotherapy drugs to get into the follicular cells. Cooling also reduces biochemical activity, making the hair follicles less susceptible to damage from chemotherapy drugs. One concern with this technique is the risk of cancer recurrence in the scalp, as perhaps this area did not receive the full dose of medication due to cooling vasoconstriction.

    After chemotherapy treatment, the hair usually grows back in very quickly, but it may change in texture. In rare cases, the hair will stay thin even after treatment has been stopped. Minoxidil can help regrow hair that is slow to return. Some chemotherapy patients wear a wig or hat to hide their hair loss until their hair grows back.

    Hair Loss in Men and Women: Diagnosis and Treatment Options

    Hair Loss in Men and Women: Diagnosis and Treatment Options

    Alopecia commonly referred to as hair loss is a condition that affects the majority of the population. It is more prevalent in males; about 30% of men experience hair loss by the age of 30, 50% by the age of 50 and increases 80% by the age of 70. It is less prevalent in females and about 40-50% of women experience hair loss by the age of 70.

    1. Anagen (Growth phase): Hair growth is stimulated by the nourishment of hair follicles via blood supply. This phase lasts for 2 to 6 years.
    2. Catagen (Transition phase): Hair follicles detach from the nourishing blood supply. This phase lasts for 1 to 2 weeks.
    3. Telogen (Resting phase): The hair dies and falls out without nourishment. This phase lasts for 5 to 6 weeks.

    During a normal hair growth cycle, 80-90% follicles are in the growth phase. Around 75 follicles shed hair each day and the same number enter a new growth phase to maintain the balance between growth and loss. This balance can be disrupted due to multiple reasons which ultimately results in hair loss:

    • Hormonal changes: Menopause, pregnancy, polycystic ovary syndrome
    • Physiologic stress: Surgery, trauma, fever, and infections
    • Chronic illnesses: Thyroid disorders, diabetes, lupus, rheumatoid arthritis, anorexia, HIV etc.
    • Diet: Rapid weight loss, strict vegetarian diet, protein deficiency etc.
    • Local trauma: Tinea capitis (fungal infection of the scalp), compulsive hair pulling
    • Genetics: Presence of HLA genes (HLA-DRB1*0401 and DQB1*0301)

    Hair loss can be categorized into different types depending on etiology. Identifying the correct hair loss type is important to determine appropriate treatment. The different types of hair loss are:

    • Androgenetic alopecia (AGA): Hereditary hair loss with gradual onset. It is the most common type of hair loss and accounts of 95% of all hair losses. It affects both males and females. Males experience loss of the frontal hairline whereas females experience thinning of the central scalp. A variety of commercial and compounded medications are available for treating AGA.
    • Alopecia areata: Autoimmune condition with an abrupt onset. It occurs in any hair-bearing area and results in patchy or complete hair loss. It can occur at any age and is due to genetic factors and/or stress. The immune system attacks the hair follicles resulting in hair loss usually in clumps. The most common treatment options include corticosteroids (injections into the scalp, topical and oral formulations) and topical immunotherapy.
    • Anagen effluvium: Hair loss that occurs during the growth phase of the hair growth cycle and results in rapid shedding of hair. It is usually a side effect of chemotherapy and radiation. It is a reversible condition and hair grows back 1-3 months after discontinuing the offending agent.
    • Telogen effluvium: Hair loss that occurs during the resting of the hair growth cycle and results in rapid shedding of the hair. It usually occurs due to metabolic/hormonal disturbances. Treating the underlying condition can reverse the condition and promote regrowth of hair.
    • Cosmetic hair damage: Hair loss that occurs due to broken/damaged hair. It occurs due to tight braiding, constant bleaching and hair treatment with chemicals.
    • Trichotillomania: Psychiatric illness characterized by pulling out hair from the scalp, eyebrows and other areas of the body. It is a mental disorder and the patient should be appropriately referred to and managed by a psychiatrist.
    • Tinea capitis: Superficial fungal infection of the scalp which results in hair loss. It is contagious and very common in children. Mild cases are treated with topical antifungals. Oral antifungals and a short course of steroids can be added to therapy for severe and/or resistant infections.

    Androgenetic alopecia:

    It is the most common type of hair loss and the difference in pattern between males and females is demonstrated below.

    1. Male-pattern hair loss: Loss of the frontal hairline.
    2. Female-pattern baldness: Thinning of the central scalp.

    The exact mechanism of hair loss in not known, however, there is a relation between the levels of dihydrotestosterone (DHT) and hair loss, especially in males.

    DHT results in the shortening of the growth phase resulting in smaller hair follicles. This process is known as miniaturizing hair. Over a period of time, the hair follicles get smaller and smaller which ultimately result in very few visible hair.

    Due to the identified role of DHT in hair loss, a lot of the treatment options target DHT to promote hair growth. AGA is diagnosed by examining the scalp and ordering blood tests to identify underlying causes such as abnormal hormonal levels, iron deficiency anemia and thyroid problems.

    Treatment options:

    1. Minoxidil: It increases blood flow to the hair follicles and prolongs the anagen (growth) phase to promote hair growth. It is FDA approved for treating androgenetic alopecia and is commercially available as Rogaine in a 2% solution and 2 and 5% foam formulation. Within 2 months the hair begins to shed less and in 4 to 8 months new hair should begin to grow. Its effectiveness is dose dependent and higher strength formulations cause more hair growth. Results are seen as early as 2 months. High strength formulations are not available commercially as it is not soluble in the standard liquid base. However, it can be compounded at a specialty pharmacy in a cream or lotion base once prescribed by the provider. Commercially available products are only effective in 30-40% people. Majority of the population will require high strength minoxidil or combination products to experience optimal results.

      Directions: Apply to a clean and dry scalp and allow 2-4 hours for the drug to penetrate the scalp. The scalp should be free of cuts or opening, applying over here can result in the absorption of the drug into the bloodstream. The effectiveness of minoxidil stabilizes after 12 to 18 month of use. It has to be continued indefinitely as discontinuation results in the loss of newly grown hair.

      Side effects: Itching, irritation, dryness, and hypertrichosis. Avoid in pregnancy and patients less than 18 years of age.

    2. Finasteride/Dutasteride: They are 5-The image inhibitor and prevent testosterone from breaking down into DHT, which is the hormone responsible for male pattern baldness. They are commonly used to treat Benign prostatic hyperplasia (BPH) and urinary incontinence in males at higher doses. Finasteride is FDA approved for treating hair loss at a lower dose and is commercially available under the brand name Propecia. It works synergistically with other ingredients to promote hair growth and can be compounded topically in combination with minoxidil and other drugs discussed below. Avoid using oral and topical finasteride together as it can increase the risk of side effects. It is not effective in most women and may require alternate agents.

      Side effects: Weakness and dizziness are commonly seen. With higher doses, patients can experience erectile dysfunction and decreased sex drive. It is not safe to use in pregnant women, including touching the pill.

    3. Spironolactone: It decreases the production of hormones such as androgens which are responsible for causing AGA. It is used as add on agent for female-pattern baldness when minoxidil is ineffective. It can be administered orally or in combination with other products such as minoxidil topically.

      Side effects: Dizziness, sleepiness, breast tenderness, and elevated potassium levels. It is not safe to use in pregnant women.

    4. Latanoprost: It acts as a prostaglandin which is a naturally occurring substance in the body which plays a role in hair growth. It is FDA approved for treating glaucoma and eyelash alopecia. Studies show that if applied topically to the scalp it can stimulate hair growth and significantly increase hair density. Effects are seen as early as 24 weeks of treatment. It is often compounded in combination with minoxidil.

    5. Corticosteroids: It is a steroid hormone which decreases the inflammation and suppresses the immune system. It is often used in conjunction with minoxidil to decrease the inflammation and irritation with higher strengths. It is commonly used to treat in alopecia areata as injected, topical, oral or any combination of the three formulations.

      Side effects: Topical formulation redness and thinning of the skin. Oral formulations are associated with weight gain, high blood sugars, swelling of legs, glaucoma etc.

    6. Progesterone: It is a hormone produced by both men and women which competes with 5-alpha reductase and prevents the conversion of testosterone to DHT. As you get older, progesterone decreases causing increased production of DHT which results in hair loss. Progesterone can be administered orally or topically compounded to stimulate hair growth.

      Side effects: Acne, insomnia, breast tenderness, fluid retention, headaches, depression. These are commonly seen with oral or high doses. The lower dose and topical formulations are generally well tolerated.

    7. Estrogen: Estrogen is directly associated with hair growth. Higher levels of estrogen are associated with thicker, fuller hair. Low estrogen levels during menopause or after pregnancy cause hair to enter the resting phase resulting in hair loss. Estrogen supplementation is a good treatment option for women suffering from AGA due to low estrogen levels. Depending on the severity and presence of other conditions it can be prescribed as an oral or topical agent. Along with hair loss, it can also help with post-menopausal symptoms such as hot flashes, difficulty sleeping, and decreased sex drive.

      Side effects: Slightly increased risk of breast cancer, increased risk of blood clots, heart disease, and stroke. These side effects are seen with higher oral doses. The lower doses and topical formulations are generally well tolerated.

    8. Azelaic acid: It is a scavenger of oxy radicals and inhibits 5-alpha reductase preventing the conversion of testosterone to DHT. It decreases the free fatty acid content of the skin surface lipids to help maximize the absorption of minoxidil. Hence, it can be used alone or in combination with minoxidil topically.

      Side effects: Burning, itching, tingling, redness, irritation of the skin.

    9. Tretinoin (Retinoic acid): It improves the absorption of minoxidil into the scalp by acting as a skin peel and increasing the permeation of minoxidil to the lower layers of the skin where hair follicles are located. It also promotes vascular proliferation which is important for hair regrowth. It is compounded in combination with minoxidil topically to increase hair growth by up to 100%.

      Side effects: Burning, stinging, irritation, peeling and crusting of the skin.

    10. Transplant: Surgical treatment option for hair loss. The healthy follicles from other parts of the scalp are transplanted to the bald area. It is considered a cosmetic procedure and is mostly not covered by the insurance and can be very expensive.

      Side effects: Bleeding, infection, swelling of the scalp.

    11. Platelet-rich plasma (PRP): It increases the blood supply to the hair follicle and triggers hair growth. It consists of three treatments in 4-6 week periods followed by maintenance treatment every 4-6 months. It is divided into three steps:

      1. Patient’s blood is drawn and put in the centrifuge for 10 minutes
      2. Blood separates into three layers platelet-poor plasma, platelet-rich plasma, and red blood cells
      3. Platelet-rich plasma is then injected into the scalp

      Side effects: Injury to blood vessels or nerves while injecting, infection, calcification and scar tissue at the injection site.

    12. Cetirizine: It is a second generation anti-histamine and also inhibits prostaglandin D2 which has some role in hair loss. Some studies have shown that using 1% topical cetirizine showed significant improvement in hair growth. The anti-inflammatory properties of cetirizine can also help with scalp inflammation and irritations.

    13. Biotin: It is a vitamin which has proven benefits for hair growth and is only effective if the patient is biotin deficient. It has no role on the DHT levels. It can be ingested orally or compounded topically to facilitate hair growth.

    A variety of topical products can be compounded to meet your needs. Some examples are:

    • Minoxidil (high strength)
    • Minoxidil/Finasteride topical solution
    • Minoxidil/Finasteride/Azelaic acid/Progesterone/Tretinoin topical solution
    • Fluocinonide/Azelaic acid/Minoxidil/Tretinoin shampoo
    • Latanoprost/Finasteride topical foam
    • Minoxidil/Finasteride/Spironolactone topical foam
    • And many more!!!

    Medical Editor: John P. Cunha, DO, FACOEP

    Last reviewed on RxList 10/25/2018

    Zyrtec (cetirizine hydrochloride) is an antihistamine that treats symptoms, such as itching, runny nose, watery eyes, and sneezing from hay fever (allergic rhinitis) and other allergies, such as allergies to molds and dust mites. Zyrtec is available in generic form and over-the-counter (OTC). Common side effects of Zyrtec include:

    • drowsiness,
    • fatigue,
    • tired feeling,
    • dizziness,
    • dry mouth,
    • sore throat,
    • cough,
    • nausea,
    • constipation, or
    • headache.

    In children, side effects of Zyrtec include:

    • stomach pain and
    • vomiting.

    The side effect of sleepiness may occur when taking Zyrtec, so do not drive a car or operate potentially dangerous machinery.

    Zyrtec is available as regular tablets and chewable tablets (5 mg and 10 mg) and syrup (1 mg/mL). It is available as an over-the-counter (OTC) drug, so no prescription is needed. Zyrtec may interact with other medicines that make you sleepy (such as other cold or allergy medicine, narcotic pain medicine, sleeping pills, muscle relaxers, and medicine for seizures, depression, or anxiety). Tell your doctor all medications and supplements you use. Zyrtec should be used during pregnancy only if clearly needed, and it is not recommended for nursing mothers.

    Our Zyrtec (cetirizine hydrochloride) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

    This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

    Cetirizine for hay fever

    This leaflet is about the use of cetirizine for hay fever.

    This leaflet has been written for parents and carers about how to use this medicine in children. Our information sometimes differs from that provided by the manufacturers, because their information is usually aimed at adult patients. Please read this leaflet carefully. Keep it somewhere safe so that you can read it again.

    Name of drug

    Common brands: Benadryl® Allergy, Piriteze, Zirtek

    Why is it important for my child to take this medicine?

    Hay fever is an allergic reaction to pollen. The body releases a chemical called histamine, which causes symptoms such as sneezing, runny nose and itchy, watery eyes. Cetirizine blocks the effects of histamine and so reduces the symptoms of hay fever.

    People get hay fever at different times of the year depending on the type of pollen they are allergic to. Your child should take cetirizine regularly during their allergy season when the pollen count is high, which will help to keep symptoms under control.

    What is cetirizine available as?

    • Tablets: 10 mg
    • Liquid medicine: 5 mg in 5 mL; sugar free versions are available

    When should I give cetirizine?

    Cetirizine is usually given once or twice each day.

    • Once a day: it can be given in the morning or the evening.
    • Twice a day: give once in the morning and once in the evening. Ideally, these times are 10–12 hours apart, for example some time between 7 and 8 am, and between 7 and 8 pm.

    Give the medicine at about the same time(s) each day so that this becomes part of your child’s daily routine, which will help you to remember.

    How much should I give?

    Your doctor will work out the amount of cetirizine (the dose) that is right for your child. The dose will be shown on the medicine label.

    It is important that you follow your doctor’s instructions about how much to give.

    How should I give it?

    Tablets should be swallowed with a glass of water, milk or juice. Your child should not chew the tablet.

    You can crush the tablet and mix it with a small amount of soft food such as yogurt, jam or mashed potato. Make sure your child swallows it straight away, without chewing.

    Liquid medicine: Measure out the right amount using a medicine spoon or oral syringe. You can get these from your pharmacist. Do not use a kitchen teaspoon as it will not give the right amount.

    When should the medicine start working?

    Cetirizine starts to work within 30 – 60 minutes after being taken.

    What if my child is sick (vomits)?

    • If your child is sick less than 30 minutes after having a dose of cetirizine, give them the same dose again.
    • If your child is sick more than 30 minutes after having a dose of cetirizine, you do not need to give them another dose. Wait until the next normal dose.

    If your child is sick again, seek advice from your GP, pharmacist or hospital. They will decide what to do based on your child’s condition and the specific medicine involved.

    What if I forget to give it?

    If you normally give it once a day in the morning

    • Give the missed dose when you remember during the day.

    If you normally give it once a day in the evening

    • If you remember before bedtime, give the missed dose. If you remember after this, you do not need to wake your child up to give them the missed dose. You can give the missed dose in the morning.

    If you normally give it twice a day

    • If you remember up to 4 hours after you should have given a dose, give your child the missed dose. For example, if you usually give a dose at about 7 am, you can give the missed dose at any time up to 11 am. If you remember after that time, do not give the missed dose. Wait until the next normal dose.

    What if I give too much?

    Cetirizine is generally a safe drug, and you are unlikely to do harm if you give your child an extra dose of cetirizine by mistake. If you are worried that you may have given your child too much, contact your doctor or local NHS services (111 in England and Scotland; 0845 4647 in Wales). Have the medicine packet with you if you telephone for advice.

    Are there any possible side-effects?

    We use medicines to make our children better, but sometimes they have other effects that we don’t want (side-effects).

    Side-effects you must do something about

    If your child gets palpitations (they may feel a fluttery feeling in chest or say that their heart is racing), contact your doctor straight away or take your child to hospital.

    Other side-effects you need to know about
    • Your child may feel sleepy, drowsy or sluggish after taking cetirizine. This can last for a few hours, so it may be better to give cetirizine in the evening rather than the morning.
    • Your child may get a dry mouth. Eating citrus fruits (e.g. oranges) or taking sips of water may help.
    • Your child’s eyesight may be blurred (fuzzy).
    • Your child may have constipation (difficulty doing a poo, or doing a poo less often than usual). Encourage them to drink plenty of fluid and to eat foods that contain fibre (e.g. wholemeal foods, fruit and vegetables). If this is still a problem after 2 weeks, contact your doctor.
    • Your child may find that they urinate (do a wee) less often, or have difficulty doing a wee.
    • Your child may feel light headed and faint (dizziness). Encourage them not to stand up too quickly, and to sit or lie down if they feel dizzy.
    • They may get headaches when they first start taking cetirizine.

    There may, sometimes, be other side-effects that are not listed above. If you notice anything unusual and are concerned, contact your doctor. You can report any suspected side-effects to a UK safety scheme at

    Can other medicines be given at the same time as cetirizine?

    • You can give your child medicines that contain paracetamol or ibuprofen, unless your doctor has told you not to.
    • Check with your doctor or pharmacist before giving any other medicines to your child. This includes herbal or complementary medicines.

    Is there anything else I need to know about cetirizine?

    • If your child continues to get symptoms of hay fever, contact your doctor. They may consider other treatments.
    • Symptoms of eczema and asthma may get worse during the hay fever season. If this happens, contact your doctor.

    General advice about medicines

    • Try to give medicines at about the same times each day, to help you remember.
    • Only give this medicine to your child. Never give it to anyone else, even if their condition appears to be the same, as this could do harm.
    • If you think someone else may have taken the medicine by accident, contact your doctor for advice.
    • Make sure that the medicine you have at home has not reached the ‘best before’ or ‘use by’ date on the packaging. Give old medicines to your pharmacist to dispose of.

    Where should I keep this medicine?

    • Keep the medicine in a cupbord, away from heat and direct sunlight. It does not need to be kept in the fridge.
    • Make sure that children cannot see or reach the medicine.
    • Keep the medicine in the container it came in.

    Who to contact for more information

    Your doctor, pharmacist or nurse will be able to give you more information about cetirizine and about other medicines used to treat hay fever.

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