Cetimax (Cetirizine 10 mg)
Second-generation antihistamine for allergy relief
Quick Facts About Cetimax
Key Takeaways About Cetimax
- Effective allergy relief: Cetimax (cetirizine 10 mg) provides 24-hour relief from symptoms of allergic rhinitis and chronic urticaria with a single daily dose
- Less sedating than older antihistamines: As a second-generation antihistamine, cetirizine causes significantly less drowsiness than first-generation options like diphenhydramine or chlorpheniramine
- Rapid onset: Effects typically begin within 20 to 60 minutes of taking the tablet, with peak plasma concentration reached in about 1 hour
- Available without prescription: Cetimax is an OTC medication in most countries, making it easily accessible for self-treatment of mild to moderate allergy symptoms
- Dose adjustment for kidney problems: Patients with moderate to severe renal impairment should use a reduced dose – consult your healthcare provider for guidance
What Is Cetimax and What Is It Used For?
Cetimax contains cetirizine dihydrochloride 10 mg, a potent and selective second-generation antihistamine that blocks peripheral H1 histamine receptors. It is used to relieve symptoms of allergic rhinitis (hay fever), perennial allergic rhinitis, and chronic idiopathic urticaria (hives) in adults and children aged 6 years and older.
Cetirizine, the active ingredient in Cetimax, belongs to the piperazine class of antihistamines and is the active carboxylic acid metabolite of hydroxyzine. Unlike first-generation antihistamines such as diphenhydramine and chlorpheniramine, cetirizine has been specifically designed to minimize crossing the blood-brain barrier, which results in significantly less sedation and cognitive impairment. This pharmacological advantage has made cetirizine one of the most widely prescribed and recommended antihistamines worldwide since its introduction in the late 1980s.
The mechanism of action of cetirizine involves selective and potent antagonism of peripheral histamine H1 receptors. When an allergen enters the body, the immune system triggers mast cells and basophils to release histamine, which then binds to H1 receptors on various tissues. This binding causes the hallmark symptoms of allergic reactions: vasodilation (leading to nasal congestion and skin redness), increased vascular permeability (causing runny nose and watery eyes), smooth muscle contraction (contributing to bronchoconstriction), and stimulation of sensory nerve endings (producing itching and sneezing). Cetirizine works by competitively blocking histamine from binding to these receptors, thereby preventing or reducing these allergic symptoms.
Beyond its antihistamine properties, cetirizine has also been shown to possess anti-inflammatory effects. Research published in peer-reviewed journals has demonstrated that cetirizine inhibits the migration and accumulation of eosinophils – a type of white blood cell heavily involved in allergic inflammation – during the late-phase allergic response. This dual action on both the immediate histamine-mediated response and the later inflammatory phase contributes to the comprehensive symptom relief observed with cetirizine therapy.
Cetimax is indicated for the following conditions:
- Seasonal allergic rhinitis (hay fever): Relief of sneezing, rhinorrhea (runny nose), nasal itching, and ocular symptoms (itchy, watery, red eyes) caused by outdoor allergens such as pollen from trees, grasses, and weeds
- Perennial allergic rhinitis: Year-round relief of nasal and ocular symptoms triggered by indoor allergens including house dust mites, pet dander, and mold spores
- Chronic idiopathic urticaria (hives): Reduction of itching (pruritus) and the number and size of wheals (hives) in patients with chronic urticaria of unknown cause
- Allergic skin conditions: Management of pruritus associated with various allergic dermatoses
Cetimax treats the symptoms of allergic reactions but does not cure the underlying allergy. If your symptoms persist or worsen despite regular use, or if you develop new symptoms, consult your healthcare provider for a comprehensive allergy evaluation. Allergen avoidance and, in some cases, allergen immunotherapy may be recommended as part of a long-term management strategy.
What Should You Know Before Taking Cetimax?
Before taking Cetimax, you should be aware of several important contraindications, warnings, and precautions. While cetirizine is generally well tolerated, certain individuals should avoid it or use it with caution, including those with severe kidney disease, epilepsy risk factors, or those who are pregnant or breastfeeding.
Contraindications
Cetimax should not be taken if you have any of the following:
- Hypersensitivity: Known allergy to cetirizine dihydrochloride, hydroxyzine, any piperazine derivatives, or any of the excipients in the tablet formulation
- Severe renal impairment: Patients with end-stage renal disease (creatinine clearance <10 mL/min) should not take cetirizine, as the drug is primarily eliminated through the kidneys and may accumulate to dangerous levels
- Hereditary conditions: Patients with rare hereditary problems of galactose intolerance, total lactase deficiency, or glucose-galactose malabsorption should not take this medicine if it contains lactose as an excipient
Warnings and Precautions
Talk to your doctor or pharmacist before taking Cetimax if you have any of the following conditions or situations:
- Renal impairment: Patients with moderate kidney disease (creatinine clearance 30–49 mL/min) should take a reduced dose of 5 mg once daily. Patients with mild renal impairment (creatinine clearance 50–79 mL/min) may not require dose adjustment but should be monitored
- Hepatic impairment: Although cetirizine undergoes minimal hepatic metabolism, patients with significant liver disease combined with renal impairment may require dose reduction
- Epilepsy and seizure risk: Cetirizine should be used with caution in patients with epilepsy or those at risk of seizures, as antihistamines may lower the seizure threshold in susceptible individuals
- Urinary retention risk: Patients with conditions predisposing to urinary retention (such as spinal cord lesions or prostatic hyperplasia) should use cetirizine with caution, as antihistamines may exacerbate urinary retention
- Drowsiness: Although less sedating than first-generation antihistamines, cetirizine can cause somnolence in some individuals. Exercise caution when driving or operating machinery until you know how the medication affects you
- Alcohol: Concurrent use of alcohol with cetirizine may enhance sedative effects. It is advisable to limit or avoid alcohol consumption while taking this medication
Pregnancy and Breastfeeding
If you are pregnant, planning to become pregnant, or breastfeeding, consult your healthcare provider before taking Cetimax. Cetirizine is classified as FDA Pregnancy Category B, meaning that animal reproduction studies have not demonstrated a risk to the fetus, but there are no adequate and well-controlled studies in pregnant women. Cetirizine should be used during pregnancy only if clearly needed and the potential benefits outweigh the potential risks.
Cetirizine is excreted into human breast milk at concentrations approximately 25% of those in maternal plasma. Because of the potential for adverse effects in nursing infants, breastfeeding women should consult a physician before using Cetimax. The decision to discontinue breastfeeding or to discontinue the drug should take into account the importance of the medication to the mother. If cetirizine is used during breastfeeding, the infant should be monitored for any unusual drowsiness or irritability.
Although cetirizine is classified as a non-sedating antihistamine, clinical studies show that approximately 10–14% of patients taking the 10 mg dose experience some degree of drowsiness. Do not drive, operate heavy machinery, or engage in potentially hazardous activities until you know how Cetimax affects your alertness and reaction time, especially during the first few days of treatment.
How Does Cetimax Interact with Other Drugs?
Cetirizine has a relatively favorable drug interaction profile compared to many other medications. However, certain drugs can affect how cetirizine works or increase the risk of side effects. The most clinically significant interactions involve central nervous system depressants, theophylline, and ritonavir.
Unlike some first-generation antihistamines and the second-generation antihistamine terfenadine (which was withdrawn from the market), cetirizine does not undergo significant cytochrome P450 metabolism. This means it has fewer pharmacokinetic drug interactions than many other antihistamines. However, pharmacodynamic interactions – where the combined effects of cetirizine and another drug are additive or synergistic – remain clinically important.
Drug interaction studies have been performed with cetirizine and several commonly used medications. A study with theophylline (400 mg once daily) showed a small (16%) decrease in cetirizine clearance, suggesting that theophylline may modestly increase cetirizine blood levels. No significant interactions were found with pseudoephedrine, cimetidine, ketoconazole, erythromycin, or azithromycin in dedicated pharmacokinetic studies. However, the absence of interaction in controlled studies does not guarantee the absence of interaction in all clinical settings.
| Interacting Drug | Severity | Effect | Clinical Advice |
|---|---|---|---|
| Alcohol (ethanol) | Moderate | Enhanced CNS depression, increased sedation and impaired psychomotor performance | Avoid or limit alcohol while taking cetirizine |
| Theophylline | Moderate | 16% decrease in cetirizine clearance; possible increased cetirizine exposure | Monitor for increased sedation; no dose adjustment usually needed |
| Ritonavir | Moderate | Increased cetirizine AUC by approximately 42% and increased half-life by 53% | Consider dose reduction of cetirizine; monitor for side effects |
| CNS depressants (benzodiazepines, opioids, sedatives) | Moderate | Additive central nervous system depression; enhanced sedation | Use combination with caution; monitor for excessive sedation |
| Anticholinergic drugs | Minor | Possible additive anticholinergic effects (dry mouth, urinary retention) | Monitor for anticholinergic symptoms; cetirizine has minimal anticholinergic activity |
| Pseudoephedrine | None | No clinically significant pharmacokinetic interaction | Safe to combine; commonly available as fixed-dose combination |
Major Interactions
The most important drug interactions with cetirizine involve substances that enhance central nervous system depression. When cetirizine is combined with alcohol, benzodiazepines (such as diazepam or lorazepam), opioid analgesics, barbiturates, or other sedating medications, the sedative effects can be additive or even synergistic. This combination may significantly impair cognitive function, reaction time, and the ability to perform tasks requiring mental alertness. Patients taking any CNS depressant should discuss the addition of cetirizine with their healthcare provider.
Ritonavir, a protease inhibitor used in the treatment of HIV infection, has been shown to increase cetirizine exposure by approximately 42% (as measured by area under the curve) and extend its half-life by 53%. Patients taking ritonavir-based antiretroviral regimens who require antihistamine therapy should discuss appropriate dosing adjustments with their physician.
Minor Interactions
Cetirizine has minimal anticholinergic activity compared to first-generation antihistamines. However, when combined with other drugs possessing anticholinergic properties – such as tricyclic antidepressants, certain antipsychotics, or bladder antispasmodics – there may be a slight additive effect on anticholinergic side effects like dry mouth, constipation, and urinary retention. These interactions are generally mild and rarely clinically significant, but patients should be aware of the possibility.
No significant pharmacokinetic interactions have been identified between cetirizine and commonly used medications including cimetidine, ketoconazole, erythromycin, azithromycin, or glipizide. This favorable interaction profile is one of the reasons cetirizine is considered a good choice for patients taking multiple medications.
What Is the Correct Dosage of Cetimax?
The standard adult dose of Cetimax is one 10 mg tablet taken once daily, with or without food. The tablet should be swallowed whole with a glass of water. Dosage adjustments are necessary for patients with kidney impairment, elderly patients, and children under 12 years of age.
Adults
Adults and Adolescents (12 years and older)
The recommended dose is 10 mg once daily (one tablet), taken at any time of day with or without food. Some patients may find that taking the dose in the evening reduces any daytime drowsiness. The tablet should be swallowed whole with water and should not be crushed or chewed. The 24-hour duration of action allows for convenient once-daily dosing. For patients who experience drowsiness at 10 mg, a dose of 5 mg (half a tablet) once daily may be sufficient and is an acceptable starting dose.
Children
Children Aged 6 to 12 Years
The recommended dose is 5 mg twice daily (half a tablet in the morning and half in the evening) or 10 mg once daily (one tablet). The choice between these two regimens may depend on the child's body weight: children weighing less than 30 kg may benefit from the 5 mg twice daily regimen, while those weighing 30 kg or more can take the full 10 mg once daily. Liquid formulations of cetirizine are generally preferred for younger children. Always consult a pediatrician for appropriate dosing in children.
Children Under 6 Years
Cetimax 10 mg film-coated tablets are not recommended for children under 6 years of age due to the inability to achieve appropriate dose adjustment with this tablet formulation. Oral solution (liquid) forms of cetirizine are available in lower doses (2.5 mg for ages 2–5 years and 2.5 mg for ages 1–2 years) and should be used instead. Always follow pediatric dosing guidelines and consult a healthcare provider.
Elderly
Elderly Patients (65 years and older)
No specific dose adjustment is required for elderly patients based on age alone, provided they have normal renal function. However, because kidney function naturally declines with age, elderly patients are more likely to have reduced renal clearance. A starting dose of 5 mg once daily may be prudent in elderly patients, with the dose increased to 10 mg if needed and well tolerated. Elderly patients should be monitored for excessive sedation, particularly during the first few days of therapy.
| Patient Group | Recommended Dose | Frequency | Special Notes |
|---|---|---|---|
| Adults (≥12 years) | 10 mg | Once daily | May reduce to 5 mg if drowsiness occurs |
| Children (6–12 years, ≥30 kg) | 10 mg | Once daily | Alternatively, 5 mg twice daily |
| Children (6–12 years, <30 kg) | 5 mg | Twice daily | Liquid formulation preferred |
| Elderly (≥65 years) | 5–10 mg | Once daily | Start at 5 mg; assess renal function |
| Renal impairment (CrCl 30–49) | 5 mg | Once daily | Mandatory dose reduction |
| Renal impairment (CrCl <30) | 5 mg | Every other day | Consult physician; close monitoring |
Missed Dose
If you forget to take a dose of Cetimax, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a forgotten one. Because cetirizine has a relatively long duration of action (approximately 24 hours), a single missed dose is unlikely to cause a significant return of symptoms immediately, but you may notice some decrease in symptom control later in the day.
Overdose
In the event of an overdose with cetirizine, symptoms may include drowsiness, restlessness, irritability, and in severe cases, urinary retention or tremor. In adults, significant symptoms have been reported after ingestion of doses five times or more the recommended daily dose (50 mg or more). There is no specific antidote for cetirizine overdose. Treatment should be symptomatic and supportive. Gastric lavage or administration of activated charcoal may be considered if the overdose occurred recently (within 1–2 hours). Cetirizine is not effectively removed by hemodialysis. If you suspect an overdose, contact your local poison control center or seek emergency medical attention immediately.
If you or someone has taken too many Cetimax tablets, seek immediate medical advice by calling your local poison control center or going to the nearest emergency department. Bring the medication packaging with you so healthcare providers can identify the product and dose taken.
What Are the Side Effects of Cetimax?
Cetirizine is generally well tolerated, but like all medications, it can cause side effects. The most commonly reported side effects include drowsiness (somnolence), headache, dry mouth, and fatigue. Most side effects are mild and tend to diminish with continued use. Serious adverse reactions are rare.
Clinical trials involving thousands of patients have established a comprehensive safety profile for cetirizine at the 10 mg dose. The side effect frequencies listed below are based on data from controlled clinical trials and post-marketing surveillance reports from the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA). Side effects are categorized by frequency according to the MedDRA convention used by regulatory agencies.
Very Common (>1/10)
- Somnolence (drowsiness) – reported in approximately 10–14% of patients at the 10 mg dose, compared to about 6% with placebo. Tends to diminish after the first week of treatment
Common (1/10 to 1/100)
- Headache – usually mild and self-limiting
- Dry mouth – less frequent than with first-generation antihistamines
- Fatigue – general tiredness, typically mild
- Dizziness – may be more pronounced in elderly patients
- Nausea – can be minimized by taking with food
- Pharyngitis – sore throat, reported at rates similar to placebo
Uncommon (1/100 to 1/1,000)
- Abdominal pain – stomach discomfort or pain
- Diarrhea – usually self-resolving
- Pruritus (itching) – paradoxical itching
- Skin rash – allergic skin reaction to the medication itself
- Asthenia – weakness or lack of energy
- Paresthesia – tingling or numbness
Rare (<1/1,000)
- Tachycardia – rapid heartbeat
- Allergic reactions – including angioedema and anaphylaxis (very rare)
- Hepatic dysfunction – elevated liver enzymes, hepatitis (very rare)
- Urinary retention – difficulty urinating
- Weight gain – increased appetite reported very rarely
- Thrombocytopenia – low platelet count (very rare, from post-marketing reports)
- Convulsions – seizures (very rare, mainly in patients with predisposing factors)
- Orofacial dyskinesia – involuntary facial movements (isolated post-marketing reports)
Most side effects of cetirizine are dose-dependent and tend to be less frequent at the 5 mg dose compared to the 10 mg dose. Drowsiness, the most commonly reported side effect, typically diminishes after the first several days of continuous use as the body adjusts to the medication. If you experience any side effects that are persistent, bothersome, or concerning, consult your healthcare provider. In the rare event of a severe allergic reaction (difficulty breathing, swelling of the face, lips, tongue, or throat), discontinue the medication and seek emergency medical help immediately.
Contact your healthcare provider if you experience severe drowsiness that interferes with daily activities, difficulty urinating, a rapid or irregular heartbeat, signs of an allergic reaction (hives, facial swelling, difficulty breathing), or any other unusual symptoms that concern you. If you experience signs of a serious allergic reaction, seek emergency medical attention immediately.
How Should You Store Cetimax?
Store Cetimax at room temperature below 25°C (77°F) in the original packaging to protect from moisture and light. Keep out of reach and sight of children. Do not use after the expiry date printed on the packaging.
Proper storage of Cetimax is essential to maintain the effectiveness and safety of the medication. Film-coated tablets should be stored in their original blister pack or container until ready for use. This protects the tablets from environmental factors that can degrade the active ingredient. Exposure to excessive heat, direct sunlight, or high humidity can reduce the potency of cetirizine and alter the physical properties of the tablet coating.
Do not store Cetimax in the bathroom or near the kitchen sink, as these areas tend to be warm and humid. Avoid transferring the tablets to a different container unless it provides equivalent protection from moisture and light. When traveling, keep the medication in your carry-on luggage rather than checked baggage, where it may be exposed to temperature extremes in the aircraft cargo hold.
Check the expiry date before taking each dose. The expiry date refers to the last day of the stated month. Do not use Cetimax if the expiry date has passed, even if the tablets appear to look normal. Expired medication may not only be less effective but could potentially form degradation products that might be harmful.
Dispose of unused or expired Cetimax tablets responsibly. Do not flush them down the toilet or throw them in household waste. Return unused medication to your pharmacy for proper disposal through a medication take-back program. Many pharmacies and community organizations offer medication disposal services at no charge. Proper disposal helps prevent environmental contamination and accidental ingestion by children or pets.
What Does Cetimax Contain?
Each Cetimax film-coated tablet contains cetirizine dihydrochloride 10 mg as the active ingredient, along with several inactive excipients that ensure the tablet's stability, proper dissolution, and ease of swallowing.
The active ingredient in Cetimax is cetirizine dihydrochloride, present at a dose of 10 mg per tablet. Cetirizine dihydrochloride is the racemic mixture of the (R)- and (S)-enantiomers. The (R)-enantiomer, known as levocetirizine, accounts for the majority of the antihistamine activity and is available as a separate medication under different brand names. The molecular formula of cetirizine dihydrochloride is C21H25ClN2O3·2HCl, and it appears as a white crystalline powder that is freely soluble in water.
The inactive ingredients (excipients) in Cetimax film-coated tablets typically include:
- Microcrystalline cellulose – used as a filler and binder to give the tablet its structure and appropriate size
- Lactose monohydrate – serves as a filler and aids in tablet compression (note: patients with lactose intolerance should be aware of this ingredient)
- Colloidal silicon dioxide – acts as a glidant to improve powder flow during manufacturing
- Magnesium stearate – a lubricant that prevents the tablet from sticking to manufacturing equipment
- Hypromellose (HPMC) – a key component of the film coating that protects the tablet and makes it easier to swallow
- Titanium dioxide – provides the white color of the film coating and protects the active ingredient from light degradation
- Macrogol (polyethylene glycol) – used as a plasticizer in the film coating to improve its flexibility and appearance
Patients with known allergies to any of the listed excipients should inform their pharmacist and consider alternative cetirizine formulations that do not contain the problematic ingredient. The exact excipient composition may vary slightly between different manufacturers and batches, so always refer to the patient information leaflet included with your specific product for the most accurate and up-to-date ingredient list.
Frequently Asked Questions About Cetimax
Cetimax contains cetirizine 10 mg, a second-generation antihistamine used to relieve symptoms of seasonal allergic rhinitis (hay fever), perennial allergic rhinitis (year-round allergies), and chronic idiopathic urticaria (hives). It effectively treats sneezing, runny nose, itchy and watery eyes, and itchy skin caused by allergic reactions. It works by blocking histamine H1 receptors, preventing the allergic cascade that produces these symptoms.
Cetirizine is classified as pregnancy category B, meaning animal studies have not shown fetal harm, but there are no adequate studies in pregnant women. Use during pregnancy only if clearly needed and after consulting your healthcare provider. Cetirizine is excreted into breast milk at approximately 25% of maternal plasma concentrations, so breastfeeding women should consult a physician before use and monitor infants for any unusual drowsiness.
Cetimax (cetirizine) is a second-generation antihistamine designed to cause less sedation than older antihistamines. However, at the 10 mg dose, approximately 10–14% of users report some degree of somnolence (drowsiness), particularly when first starting the medication or when combined with alcohol. This side effect tends to diminish after the first few days of use. If drowsiness is bothersome, consider taking the tablet in the evening, reducing the dose to 5 mg, or consulting your pharmacist about alternative antihistamines.
Cetimax 10 mg film-coated tablets are recommended for adults and children aged 12 years and older at the full 10 mg dose. Children aged 6 to 12 years may take half a tablet (5 mg) twice daily or one full 10 mg tablet once daily, depending on their weight. For children under 6 years, liquid formulations of cetirizine are preferred as they allow more precise dose adjustment. Always consult a pediatrician before giving any medication to children, especially for those under 6 years of age.
Yes, Cetimax is classified as an over-the-counter (OTC) medication in most countries, meaning you can purchase it directly from a pharmacy without a prescription. OTC availability may vary by region. Even though no prescription is needed, it is advisable to consult a pharmacist if you have kidney problems, liver disease, are taking other medications, or are pregnant or breastfeeding. If symptoms persist for more than two weeks without improvement, consult a healthcare provider.
Cetimax (cetirizine) typically begins working within 20 to 60 minutes after ingestion, with peak plasma concentrations reached in approximately 1 hour. The antihistamine effect lasts for at least 24 hours, supporting once-daily dosing. Clinical studies have demonstrated that some patients experience symptom improvement within 20 minutes of taking the tablet, making cetirizine one of the faster-acting oral antihistamines available.
References and Sources
This article is based on internationally recognized medical and pharmaceutical guidelines. All information has been reviewed by qualified healthcare professionals and follows evidence-based principles.
- European Medicines Agency (EMA). Cetirizine Dihydrochloride – Summary of Product Characteristics (SmPC). EMA, 2024. Available at: www.ema.europa.eu
- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd List, 2023. Geneva: World Health Organization, 2023.
- British National Formulary (BNF). Cetirizine Hydrochloride: Prescribing and Dosing Information. NICE, 2024. Available at: bnf.nice.org.uk
- U.S. Food and Drug Administration (FDA). Cetirizine Hydrochloride – Drug Label Information. FDA, 2024. Available at: www.fda.gov
- Simons FER, Simons KJ. Histamine and H1-antihistamines: celebrating a century of progress. Journal of Allergy and Clinical Immunology. 2011;128(6):1161–1174.
- Church MK, Maurer M, et al. Risk of first-generation H1-antihistamines: a GA2LEN position paper. Allergy. 2010;65(4):459–466.
- Goodman & Gilman's. The Pharmacological Basis of Therapeutics. 14th Edition. McGraw-Hill Education, 2023.
About the Medical Editorial Team
This article has been written and reviewed by iMedic's Medical Editorial Team, consisting of licensed physicians and specialists in clinical pharmacology with expertise in drug safety, pharmacovigilance, and evidence-based medicine.
iMedic Medical Editorial Team – specialists in clinical pharmacology and drug information. All content is researched and written using peer-reviewed sources and international pharmaceutical guidelines.
iMedic Medical Review Board – independent panel of qualified physicians who review all drug information content for accuracy, completeness, and clinical relevance according to EMA, FDA, and WHO standards.
Editorial Standards: All pharmaceutical content on iMedic follows strict editorial standards based on the GRADE evidence framework. We do not accept any form of pharmaceutical industry sponsorship or advertising. Our content is independent, evidence-based, and written for patients and caregivers. Read more about our editorial standards.