Azomyr (Desloratadine)
Second-generation antihistamine for allergic rhinitis and chronic urticaria
Azomyr contains the active ingredient desloratadine, a selective, long-acting, non-sedating second-generation antihistamine. It is primarily used to relieve symptoms of allergic rhinitis (hay fever) and chronic idiopathic urticaria (hives). Desloratadine works by blocking histamine H1 receptors, preventing allergic responses such as sneezing, runny nose, nasal itching, and skin rash. It is taken once daily as a 5 mg film-coated tablet and provides 24-hour symptom relief with minimal sedation.
Quick Facts
Key Takeaways
- Azomyr contains desloratadine, the active metabolite of loratadine, providing potent antihistamine action with minimal drowsiness.
- It is approved for both allergic rhinitis (seasonal and perennial) and chronic idiopathic urticaria in adults and adolescents aged 12 and older.
- The standard dose is one 5 mg tablet once daily, with or without food, providing 24-hour symptom relief.
- Desloratadine has a favorable safety profile with side effects comparable to placebo in clinical trials.
- Patients with severe kidney or liver impairment should use Azomyr with caution and under medical supervision.
What Is Azomyr and What Is It Used For?
Azomyr belongs to the class of second-generation (non-sedating) antihistamines. Its active ingredient, desloratadine, is the principal active metabolite of loratadine and has been extensively studied in numerous randomized controlled trials. The drug was first approved by the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA) and has been widely prescribed worldwide since the early 2000s.
Desloratadine selectively antagonizes peripheral histamine H1 receptors. When allergens such as pollen, dust mites, pet dander, or mold spores enter the body, the immune system releases histamine from mast cells and basophils. Histamine binds to H1 receptors on blood vessels, nerve endings, and smooth muscle, leading to the classic symptoms of allergic rhinitis: sneezing, nasal itching, rhinorrhea (runny nose), nasal congestion, and ocular symptoms (itchy, watery, red eyes). By occupying these receptors, desloratadine prevents histamine from exerting its effects, providing effective symptom relief.
In addition to its antihistamine properties, desloratadine has been shown to have anti-inflammatory and anti-allergic effects. In vitro and in vivo studies demonstrate that it inhibits the release of pro-inflammatory cytokines (such as IL-4, IL-6, and IL-13), reduces the expression of adhesion molecules (P-selectin, ICAM-1), and decreases the production of superoxide anion by polymorphonuclear neutrophils. These pleiotropic effects contribute to its clinical efficacy beyond simple histamine receptor blockade.
Approved Indications
Azomyr is indicated for the relief of symptoms associated with:
- Allergic rhinitis (seasonal and perennial): Desloratadine effectively reduces sneezing, rhinorrhea, nasal pruritus, nasal congestion, and ocular symptoms (itching, tearing, and redness). Seasonal allergic rhinitis is triggered by outdoor allergens such as tree, grass, and weed pollen, while perennial allergic rhinitis is typically caused by indoor allergens such as dust mites, mold, and animal dander.
- Chronic idiopathic urticaria (CIU): Azomyr reduces pruritus (itching) and the number and size of wheals (hives). CIU is characterized by recurrent episodes of urticaria lasting six weeks or longer without an identifiable external cause. Clinical trials have demonstrated that desloratadine 5 mg significantly improves pruritus scores and reduces the interference of hives with sleep and daily activities.
How It Works: Mechanism of Action
Desloratadine is a tricyclic compound with potent and selective peripheral H1 receptor antagonist activity. Unlike first-generation antihistamines (such as diphenhydramine, chlorpheniramine, or hydroxyzine), desloratadine does not readily cross the blood-brain barrier. This pharmacological characteristic explains its low propensity to cause sedation and cognitive impairment, making it suitable for daytime use including driving and operating machinery in most patients.
After oral administration, desloratadine is well absorbed from the gastrointestinal tract. It reaches peak plasma concentrations (Cmax) in approximately 3 hours. Food does not affect the bioavailability of desloratadine, so Azomyr can be taken with or without meals. The drug is extensively metabolized in the liver, primarily by CYP3A4 and to a lesser extent CYP2D6, to form 3-hydroxydesloratadine, which is subsequently glucuronidated. The elimination half-life of desloratadine averages approximately 27 hours, supporting once-daily dosing and providing consistent 24-hour coverage.
What Should You Know Before Taking Azomyr?
Before starting Azomyr, it is essential to inform your healthcare provider about your complete medical history, current medications, and any known allergies. Although desloratadine has a favorable safety profile, certain conditions and situations require special attention. The following information will help you and your doctor determine whether Azomyr is appropriate for you.
Contraindications
Azomyr should not be taken in the following situations:
- Hypersensitivity: Do not use Azomyr if you are allergic to desloratadine, loratadine (since desloratadine is a metabolite of loratadine), or any of the excipients listed in the tablet formulation. Allergic reactions to these substances, though rare, can include skin rash, urticaria, pruritus, dyspnea, and in very rare cases, anaphylaxis.
Warnings and Precautions
Special caution is required in the following situations:
- Severe renal impairment: Desloratadine is partially eliminated through the kidneys. Patients with severe renal impairment (creatinine clearance less than 30 mL/min) should use Azomyr with caution and under medical supervision, as plasma concentrations of desloratadine may be elevated.
- Hepatic impairment: Since desloratadine is extensively metabolized in the liver, patients with moderate to severe hepatic impairment may have higher plasma levels of the drug. Dose adjustment or alternative treatment may be necessary. Consult your physician.
- Phenylketonuria (PKU): Some desloratadine formulations (particularly orodispersible tablets) may contain aspartame, a source of phenylalanine. Patients with phenylketonuria should check the specific product formulation. Standard film-coated tablets of Azomyr typically do not contain aspartame.
- Seizure disorders: Although desloratadine has not been conclusively linked to seizures, patients with a history of convulsive disorders should use antihistamines with caution and inform their treating physician.
- Lactose intolerance: Azomyr film-coated tablets contain lactose monohydrate. Patients with rare hereditary problems of galactose intolerance, total lactase deficiency, or glucose-galactose malabsorption should not take this medicine.
Pregnancy and Breastfeeding
The safety of desloratadine during pregnancy has not been established through adequate controlled studies in humans. Animal reproduction studies have not demonstrated teratogenic effects, but animal data do not always predict human responses. Azomyr should only be used during pregnancy if the expected benefit to the mother justifies the potential risk to the fetus. Always discuss the risks and benefits with your healthcare provider before taking any medication during pregnancy.
Desloratadine is excreted in breast milk. Because the potential effects on the nursing infant are not fully characterized, a decision should be made whether to discontinue breastfeeding or to discontinue Azomyr, taking into account the importance of the drug to the mother. The concentration of desloratadine in breast milk is relatively low, and short-term exposure is unlikely to cause adverse effects in most infants. Nevertheless, caution is advised, and consultation with a healthcare professional is recommended.
If you experience any signs of a serious allergic reaction (difficulty breathing, swelling of the face, lips, tongue, or throat, severe skin rash) after taking Azomyr, stop taking the medicine immediately and seek emergency medical attention.
How Does Azomyr Interact with Other Drugs?
Clinical interaction studies have evaluated the effects of several drugs on the pharmacokinetics of desloratadine. While some agents increase plasma concentrations of desloratadine, these interactions have generally not been associated with clinically meaningful changes in safety or efficacy. The following table summarizes the most relevant known interactions.
Major Interactions
No major clinically dangerous drug interactions have been identified with desloratadine. However, it is always prudent to exercise caution when combining multiple medications, particularly in patients taking drugs that affect hepatic enzyme activity.
| Interacting Drug | Effect | Clinical Significance | Recommendation |
|---|---|---|---|
| Ketoconazole | Increases desloratadine plasma concentration by approximately 45% | Low – no clinically significant ECG or adverse event changes observed | No dose adjustment generally required; monitor if used long-term |
| Erythromycin | Increases desloratadine plasma concentration by approximately 24% | Low – no clinically significant changes reported | No dose adjustment required |
| Azithromycin | Increases desloratadine plasma concentration by approximately 15% | Minimal – no adverse events noted in studies | No dose adjustment required |
| Fluoxetine | May increase desloratadine levels via CYP2D6 inhibition | Low – theoretical interaction based on metabolic pathway | Monitor for increased sedation; consult physician |
| Cimetidine | Increases desloratadine plasma concentration by approximately 12% | Minimal – unlikely to be clinically relevant | No dose adjustment required |
| Alcohol | No potentiation of alcohol-induced performance impairment in studies | Low – however, individual sensitivity may vary | Use caution; avoid excessive alcohol consumption |
| Grapefruit juice | May slightly increase desloratadine bioavailability via CYP3A4 inhibition | Minimal – not extensively studied | No specific restriction; moderate consumption acceptable |
Minor Interactions
Desloratadine does not inhibit CYP3A4, CYP2D6, CYP1A2, CYP2C9, or CYP2C19 at clinically relevant concentrations. Therefore, it is unlikely to affect the metabolism of co-administered drugs that are substrates of these enzymes. Food, including high-fat meals, does not affect the absorption of desloratadine.
Although desloratadine has a relatively low drug interaction potential, always provide your healthcare provider or pharmacist with a complete list of all prescription drugs, over-the-counter medications, herbal supplements, and vitamins you are taking. This is especially important if you take multiple medications or have liver or kidney disease.
What Is the Correct Dosage of Azomyr?
Azomyr should be taken as directed by your healthcare provider. The dosing recommendations below are based on approved prescribing information from the EMA and FDA. It is important to take the medication at approximately the same time each day to maintain consistent plasma levels and optimal symptom control. The film-coated tablet should be swallowed whole with a glass of water and should not be crushed, chewed, or split.
Adults
Adults and Adolescents (12 years and older)
The recommended dose is 5 mg (one tablet) once daily, taken orally with or without food. Treatment duration depends on the type and severity of the allergic condition:
- Seasonal allergic rhinitis: Continue for the duration of allergen exposure, typically weeks to months during pollen season.
- Perennial allergic rhinitis: May be used continuously throughout the year as long as symptoms persist.
- Chronic idiopathic urticaria: Continue as directed by your physician until symptoms resolve.
Children
Children and Adolescents
Azomyr 5 mg film-coated tablets are intended for adults and adolescents aged 12 years and older. For younger children, desloratadine is available in age-appropriate formulations:
- Children aged 6–11 years: 2.5 mg once daily (oral solution or orodispersible tablet)
- Children aged 1–5 years: 1.25 mg once daily (oral solution)
- Children aged 6–11 months: 1 mg once daily (oral solution) – in some markets, under physician supervision only
Always consult your pediatrician or pharmacist for the appropriate formulation and dosing for children.
Elderly
Elderly Patients
No dose adjustment is required for elderly patients with normal hepatic and renal function. The pharmacokinetics of desloratadine in elderly subjects are similar to those in younger adults. However, elderly patients are more likely to have decreased renal or hepatic function, and careful monitoring is recommended in patients with impaired organ function.
Missed Dose
If you forget to take a dose of Azomyr, 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 compensate for a forgotten dose. Missing a single dose is unlikely to significantly affect symptom control due to the long half-life of desloratadine.
Overdose
In case of overdose, contact your local poison control center or seek emergency medical attention immediately. In clinical trials, doses up to 45 mg (nine times the recommended dose) were administered without significant adverse effects. Symptoms of overdose may include drowsiness, increased heart rate, and headache. Treatment is symptomatic and supportive. Desloratadine is not removed by hemodialysis; it is unknown whether it is removed by peritoneal dialysis.
| Patient Group | Dose | Frequency | Formulation |
|---|---|---|---|
| Adults & Adolescents (≥12 years) | 5 mg | Once daily | Film-coated tablet |
| Children 6–11 years | 2.5 mg | Once daily | Oral solution / Orodispersible tablet |
| Children 1–5 years | 1.25 mg | Once daily | Oral solution |
| Elderly (normal organ function) | 5 mg | Once daily | Film-coated tablet |
| Severe renal impairment | 5 mg | Every other day (physician guidance) | Film-coated tablet |
What Are the Side Effects of Azomyr?
Like all medicines, Azomyr can cause side effects, although not everybody gets them. In large-scale clinical trials involving thousands of patients, desloratadine 5 mg demonstrated an adverse event profile very similar to placebo. The most commonly reported side effects were mild and transient. The following frequency classification is based on data from clinical trials and post-marketing surveillance:
Common
Affects 1 to 10 in every 100 patients
- Fatigue
- Dry mouth
- Headache
Uncommon
Affects 1 to 10 in every 1,000 patients
- Drowsiness (somnolence)
- Dizziness
- Insomnia
- Abdominal pain
- Nausea
- Diarrhea
- Increased heart rate (tachycardia)
- Muscle pain (myalgia)
Rare
Affects 1 to 10 in every 10,000 patients
- Elevated liver enzymes
- Elevated bilirubin
- Palpitations
Very Rare / Post-Marketing
Affects fewer than 1 in 10,000 patients
- Hypersensitivity reactions (including anaphylaxis, angioedema, rash, urticaria, dyspnea)
- Hepatitis
- Hallucinations
- Seizures
- Psychomotor hyperactivity
- QT prolongation (isolated case reports)
In pediatric clinical trials, the side effect profile was similar to that observed in adults. In children aged 2 to 11 years, the most commonly reported adverse events included diarrhea, fever, and insomnia, though these occurred at rates comparable to placebo. Desloratadine has not been associated with weight gain, a side effect sometimes observed with certain first-generation antihistamines.
Unlike first-generation antihistamines, desloratadine shows minimal anticholinergic activity at therapeutic doses. This means side effects such as urinary retention, blurred vision, and constipation are exceptionally rare. Additionally, desloratadine does not cause significant QTc interval prolongation at doses up to 45 mg (nine times the recommended dose), distinguishing it from certain older antihistamines like terfenadine and astemizole, which were withdrawn from the market due to cardiac concerns.
Most side effects of Azomyr are mild and resolve on their own. However, contact your healthcare provider if you experience: persistent or severe headache, unexplained skin rash or itching (which could indicate an allergic reaction to the medication), rapid or irregular heartbeat, or any symptoms that concern you. Seek emergency medical attention immediately if you develop signs of anaphylaxis (difficulty breathing, swelling of face/throat, severe dizziness).
How Should You Store Azomyr?
Proper storage of Azomyr is important to ensure the medication remains effective and safe throughout its shelf life. Film-coated tablets should be stored at room temperature, generally defined as below 30°C (86°F). Do not store the medication in the bathroom or near sources of heat or moisture, as these conditions can degrade the active ingredient and reduce its efficacy.
Keep the tablets in their original blister packaging until you are ready to take a dose. The blister pack provides protection from light and humidity. Do not transfer tablets to a different container unless specifically advised by your pharmacist. If the tablets change color, develop an unusual odor, or show visible signs of deterioration, do not use them and consult your pharmacist for a replacement.
Do not use Azomyr after the expiry date printed on the blister pack and carton. The expiry date refers to the last day of that month. Medicines should not be disposed of via wastewater or household waste. Ask your pharmacist about how to properly dispose of medicines you no longer use. These measures help protect the environment.
- Temperature: Store below 30°C (86°F)
- Light: Keep in original packaging, protected from light
- Moisture: Do not store in damp environments (avoid bathroom cabinets)
- Children: Store in a location inaccessible to children
- Expiry: Do not use after the expiration date on the package
What Does Azomyr Contain?
Understanding what Azomyr contains is important, particularly for patients with known allergies or intolerances to specific pharmaceutical excipients. The complete qualitative composition of Azomyr 5 mg film-coated tablets is listed below.
Active Ingredient
Each film-coated tablet contains 5 mg desloratadine. Desloratadine (chemical name: 8-chloro-6,11-dihydro-11-(4-piperidinylidene)-5H-benzo[5,6]cyclohepta[1,2-b]pyridine) has a molecular weight of 310.82 g/mol. It is a white to off-white crystalline powder that is slightly soluble in water.
Inactive Ingredients (Excipients)
The following excipients are present in the tablet core and film coating:
- Tablet core: Calcium hydrogen phosphate dihydrate, microcrystalline cellulose, maize starch, talc
- Film coating: Opadry (containing lactose monohydrate, hypromellose, titanium dioxide, macrogol, indigo carmine [E132])
The film coating of Azomyr tablets contains lactose monohydrate. Patients with rare hereditary problems of galactose intolerance, total lactase deficiency, or glucose-galactose malabsorption should not take this medicine. The amount of lactose per tablet is small but may still be relevant for sensitive individuals. Consult your doctor or pharmacist if you have a known lactose intolerance.
Azomyr tablets are round, blue, film-coated, and embossed with identifying markings on one side. Each tablet is packaged in aluminum/aluminum blister packs, typically available in pack sizes of 7, 10, 14, 20, 21, 30, 50, or 100 tablets, depending on the market. Not all pack sizes may be available in your country.
Frequently Asked Questions About Azomyr
Medical References
All information in this article is based on international medical guidelines and peer-reviewed sources. Evidence level: Grade 1A, based on systematic reviews and randomized controlled trials.
- European Medicines Agency (EMA). Aerius (desloratadine) – Summary of Product Characteristics (SmPC). Last updated 2024. Available at: ema.europa.eu/en/medicines/human/EPAR/aerius
- U.S. Food and Drug Administration (FDA). Clarinex (desloratadine) – Prescribing Information. Reference ID: 4920547. Available at: FDA Clarinex Label
- Bousquet J, Khaltaev N, Cruz AA, et al. Allergic Rhinitis and its Impact on Asthma (ARIA) 2008 Update. Allergy. 2008;63 Suppl 86:8-160. doi:10.1111/j.1398-9995.2007.01620.x
- World Health Organization. WHO Model List of Essential Medicines – 23rd List, 2023. Geneva: WHO; 2023.
- Zuberbier T, Abdul Latiff AH, Abuzakouk M, et al. The International EAACI/GA2LEN/EuroGuiDerm/APAAACI Guideline for the Definition, Classification, Diagnosis, and Management of Urticaria. Allergy. 2022;77(3):734-766. doi:10.1111/all.15090
- British National Formulary (BNF). Desloratadine – Drug Monograph. NICE Evidence Services. Last reviewed 2024.
- Murdoch D, Goa KL, Keam SJ. Desloratadine: An Updated Review of its Use in the Management of Allergic Disorders. Drugs. 2003;63(19):2051-2077. doi:10.2165/00003495-200363190-00010
- Bachert C. A Review of the Efficacy of Desloratadine, Fexofenadine, and Levocetirizine in the Treatment of Nasal Congestion in Patients with Allergic Rhinitis. Clinical Therapeutics. 2009;31(5):921-944.
Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, a multidisciplinary group of licensed physicians, pharmacists, and medical researchers with expertise in allergy, immunology, and clinical pharmacology.
iMedic Clinical Pharmacology Team – Specialists with expertise in drug information, pharmacokinetics, and therapeutic guidelines.
iMedic Medical Review Board – Independent panel following EMA, FDA, WHO, and BNF guidelines. All content verified against current evidence.
Our editorial process follows the GRADE evidence framework and adheres to international medical standards. All medical claims are supported by peer-reviewed research and authoritative clinical guidelines. This article contains no commercial funding or pharmaceutical company sponsorship.