Cetirizina para alergias
Piriteze, Zirtek,
Revisado por Sid DajaniÚltima atualização por Michael Stewart, MRPharmSLast updated 12 de janeiro de 2023
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Cetirizine relieves allergic symptoms.
Cetirizine is called a non-drowsy antihistamine; however, it can still cause drowsiness in a few people.
Make sure your reactions are normal before you drive, or before using tools or machines.
At a glance
Cetirizine is an antihistamine used to relieve allergy symptoms like hay fever or hives.
It works by blocking histamine, a chemical that causes allergy symptoms.
Common side effects include feeling tired, dizzy, headache, and dry mouth.
Although non-drowsy, it can cause sleepiness, so avoid driving if affected.
Avoid or limit alcohol intake as it can increase drowsiness.
Always check with a doctor or pharmacist if you are pregnant, have kidney problems, or are taking other medicines.
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Video picks for Medicamentos para alergia
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Visão Geral
Tipo de medicamento | Um anti-histamínico (não causa sonolência) |
Usado para | Allergies, such as hay fever and some allergic skin reactions |
Também chamado (Reino Unido) | Allacan®; Benadryl® Allergy; Piriteze® Allergy; Pollenshield® Hayfever; Sentanase® Allergy; Ziralton® Allergy; Zirtek®; Zirtek® Allergy |
Também chamado (EUA) | All Day Allergy®; Alleroff®; Wal-Zyr®; Zyrtec®; Zyrtec® Allergy |
Disponível como | Capsules, tablets and oral liquid medicine |
What is cetirizine used for?
Voltar ao conteúdoCetirizine is a type of antihistamínico that is used to relieve symptoms of allergies such as rinite alérgica ou urticaria (hives).
It is available on prescription from a doctor or dentist, or to buy without a prescription from pharmacies and other shops.
Cetirizine comes as tablets, capsules, and liquid medicine. Liquid formulations are usually suitable for younger children, although cetirizine is not recommended for children under 2 years old.
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How does cetirizine work?
Voltar ao conteúdoCetirizine works by blocking the effects of histamine - a chemical that is released when your body is exposed to substances such as pollen, pet fur, house dust, detergents, or insect bites.
Histamine causes allergy symptoms such as sneezing, itching, watery eyes, skin rashes, and a runny nose. By blocking histamine, cetirizine helps relieve these symptoms.
Side effects of cetirizine
Voltar ao conteúdoCommon side effects of cetirizine include:
Feeling tired or sleepy.
Tontura.
Boca seca.
Dor de cabeça.
Enjoo (náusea).
Dor de estômago.
Children may also experience additional side effects such as:
Diarreia.
Dor de garganta.
Nose irritation.
A full list of the side effects which can be associated with your medicine can be found in the manufacturer's printed information leaflet supplied with the medicine.
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How to manage cetirizine side effects
Voltar ao conteúdoCetirizine side effects (these affect fewer than 1 in 10 people) | O que posso fazer se passar por isso? |
Feeling tired, sleepy, or dizzy | Não dirija e não use ferramentas ou máquinas enquanto estiver afetado. Não beba álcool |
Boca seca | Tente mascar chiclete sem açúcar ou chupar balas sem açúcar |
Dor de cabeça | Beba bastante água e peça ao seu farmacêutico que recomende um analgésico adequado. Se as dores de cabeça continuarem, fale com o seu médico |
Feeling sick, stomach (abdominal) pain | Mantenha refeições simples - evite alimentos gordurosos ou picantes |
Diarrhoea (in children) | Beba bastante água |
Sore throat, nose irritation (in children) | Speak with a doctor if troublesome |
If you experience any other symptoms which you think may be due to cetirizine, speak with your doctor or pharmacist for further advice.
Who should not take cetirizine?
Voltar ao conteúdoTo make sure that this is the right treatment for you (or your child), before you (or they) start taking cetirizine it is important that you discuss the treatment with a doctor or pharmacist if:
Você está grávida, tentando ter um bebê ou amamentando.
You/they have any kidney problems. If so, the recommended dose will be reduced.
You/they have epilepsy.
You/they have a rare inherited blood disorder called porphyria.
You/they are taking or using any other medicines. This includes any medicines being taken which are available to buy without a prescription, as well as herbal and complementary medicines.
You/they have ever had an allergic reaction to another antihistamine, or to any other medicine.
How to take cetirizine
Voltar ao conteúdoRead the leaflet in your medicine pack before starting treatment.
Take cetirizine exactly as directed on the label or by your doctor or pharmacist.
Recommended doses of cetirizine are:
For adults and for children aged over 12 years: 10 mg taken once a day.
For children aged 6-11 years: 5 mg taken twice daily.
For children aged 2-5 years: 2.5 mg taken twice daily.
If using liquid medicine for a child, measure doses carefully using the bottle instructions.
Cetirizine can be taken with or without food. Swallow tablets with water if needed.
If you miss a dose, take the next one when due. Do not take two doses at the same time.
Obtendo o máximo do seu tratamento
Voltar ao conteúdoMost people only need cetirizine for a short time. Stop taking it once your symptoms improve.
Although it is a “non-drowsy” antihistamine, it can still cause sleepiness in some people. If this happens, do not drive, cycle, or use tools or machinery.
Be careful with alcohol, as it can increase drowsiness and side effects.
Tell your doctor or healthcare provider you are taking cetirizine before any surgery, medical treatment, or allergy tests.
Check with a pharmacist before taking other medicines, as some can increase side effects when combined with cetirizine.
How to store cetirizine
Voltar ao conteúdoMantenha todos os medicamentos fora do alcance e da vista das crianças.
Armazene em local fresco e seco, longe de calor e luz diretos.
Perguntas frequentes
Voltar ao conteúdoHow long does cetirizine take to work?
Cetirizine usually starts working within 30–60 minutes. It can help relieve allergy symptoms such as sneezing, itching, and watery eyes fairly quickly, with full effect within a few hours.
How long does cetirizine last?
A single dose of cetirizine usually lasts around 24 hours. This is why it is typically taken once daily for ongoing allergy relief.
Can you take cetirizine every day?
Yes, cetirizine can be taken daily if needed for allergies. However, it is usually used for short-term symptom relief. Speak to a doctor or pharmacist if you need it for long periods.
Can cetirizine make you sleepy?
Yes, although it is classed as a non-drowsy antihistamine, cetirizine can still cause drowsiness in some people. If this happens, avoid driving or using machinery.
Can you take cetirizine with alcohol?
It’s best to avoid or limit alcohol while taking cetirizine. Alcohol can increase drowsiness and make side effects like dizziness more likely.
Can you take cetirizine while pregnant?
Cetirizine can sometimes be used in pregnancy, but only if advised by a doctor. Always check with a healthcare professional before taking it.
Informações importantes sobre todos os medicamentos
Voltar ao conteúdoInformações importantes sobre todos os medicamentos
Se você comprar qualquer medicamento, verifique com um farmacêutico se é seguro tomá-lo com seus outros medicamentos.
Nunca tome mais do que a dose prescrita. Se suspeitar que você ou outra pessoa possa ter tomado uma overdose deste medicamento, vá ao departamento de acidentes e emergências do hospital local. Leve o recipiente com você, mesmo que esteja vazio.
Este medicamento é para você. Nunca o dê a outras pessoas, mesmo que a condição delas pareça ser a mesma que a sua.
Não guarde medicamentos vencidos ou indesejados. Leve-os à sua farmácia local, que se encarregará de descartá-los para você.
Se você tiver alguma dúvida sobre este medicamento, pergunte ao seu farmacêutico.
Relatar efeitos colaterais de um medicamento ou vacina
Se você sentir efeitos colaterais, pode relatá-los online através do Yellow Card website.

Inseguro sobre misturar medicamentos?
Verifique possíveis interações entre medicamentos, suplementos e alimentos antes de tomá-los juntos.
Perguntas frequentes
What is histamine and why does cetirizine block it?
Histamine is a chemical your body releases when it encounters substances like pollen, pet fur, or insect bites. It causes common allergy symptoms such as sneezing, itching, watery eyes, skin rashes, and a runny nose. Cetirizine works by blocking the effects of histamine which helps to relieve these symptoms.
Are there different forms of cetirizine available, and are they suitable for children?
Yes, cetirizine is available as capsules, tablets, and oral liquid medicine. The liquid formulations are usually a good option for younger children. However, cetirizine is not recommended for children under 2 years old.
What should I do if I forget to take a dose of cetirizine?
If you miss a dose of cetirizine, you should take the next one when it is due. It is important not to take two doses at the same time to make up for a missed dose.
Can I stop taking cetirizine once my allergy symptoms improve?
Yes, most people only need to take cetirizine for a short period. You can stop taking it once your allergy symptoms get better.
Is it safe to take cetirizine if I have kidney problems or epilepsy?
If you have any kidney problems, the recommended dose of cetirizine will need to be reduced. If you have epilepsy, it is important to discuss this with a doctor or pharmacist before starting treatment to make sure cetirizine is appropriate for you.
Should I tell my doctor or healthcare provider that I'm taking cetirizine before medical procedures or allergy tests?
Yes, you should inform your doctor or healthcare provider that you are taking cetirizine before any surgery, medical treatment, or allergy tests. This is an important step to ensure your safety and the effectiveness of any procedures or tests.
Leitura adicional e referências
- Manufacturer's PIL, Piriteze® Allergy Tablets (GSL); GlaxoSmithKline Consumer Healthcare, The electronic Medicines Compendium. Dated March 2022.
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About the authorView full bio

Michael Stewart, MRPharmS
Gerente de Revisão de Folhetos de Medicamentos – Contratado, Farmacêutico
BPharm (Hons), MRPharmS
Michael é um farmacêutico comunitário atuando nas Midlands e em South Yorkshire, com mais de 20 anos de experiência em aconselhamento sobre medicamentos e condições médicas. Ele tem uma sólida formação em treinamento em saúde, tendo produzido e ministrado cursos de treinamento para equipes de farmácia e funcionários de ambientes de cuidados residenciais, incluindo enfermeiros. Ele também contribuiu para conselhos consultivos de farmácia para o manejo de condições de baixa gravidade na comunidade.
About the reviewer

Sid Dajani
Sultan Dajani qualified at the London School of Pharmacy in 1994 and became the youngest elected member of the Royal Pharmaceutical Society council since its founding in 1842.
Histórico do artigo
As informações nesta página são escritas e revisadas por clínicos qualificados.
Próxima revisão agendada: 11 de jul de 2027
12 de janeiro de 2023 | Última versão

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