What the label lists and what reports show
Desloratadine side effects
Desloratadine's FDA label: “The most common adverse reactions (reported in ≥2% of adult and adolescent patients with allergic rhinitis and greater than placebo) were pharyngitis, dry mouth, myalgia, fatigue, somnolence, dysmenorrhea.” FAERS holds 10,661 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is fatigue (613 reports).
- Generic listed
Check it at the source: the desloratadine FDA label on DailyMed (effective May 17, 2025, Organon LLC); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of CLARINEX Tablets?CLARINEX may cause serious side effects, including: Allergic reactions. Stop taking CLARINEX and call your doctor right away or get emergency help if you have any of these symptoms: rash itching hives swelling of your lips, tongue, face, and throat shortness of breath or trouble breathing The most common side effects of CLARINEX in adults and children 12 years of age and older with allergic rhinitis include: sore throat dry mouth muscle pain tiredness sleepiness menstrual pain Increased sleepiness or tiredness can happen if you take more CLARINEX than your doctor prescribed to you. Tell your doctor if you have any side effect that bothers you or that does not go away. These are not all of the possible side effects of CLARINEX. For more information, ask your doctor or pharmacist. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Source: FDA drug label, Organon LLC, effective May 17, 2025 (SPL set c671342e-69a2-4ca5-abc2-8166ed4240d4), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common adverse reactions (reported in ≥2% of adult and adolescent patients with allergic rhinitis and greater than placebo) were pharyngitis, dry mouth, myalgia, fatigue, somnolence, dysmenorrhea.
Table 1: Incidence of Adverse Events Reported by ≥2% of Adult and Adolescent Allergic Rhinitis Patients Receiving CLARINEX Tablets
| Adverse Event | CLARINEX Tablets 5 mg (n=1655) | Placebo (n=1652) |
|---|---|---|
| Pharyngitis | 4.1% | 2.0% |
| Somnolence | 2.1% | 1.8% |
| Dry Mouth | 3.0% | 1.9% |
| Myalgia | 2.1% | 1.8% |
| Dysmenorrhea | 2.1% | 1.6% |
| Fatigue | 2.1% | 1.2% |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following adverse reactions are discussed in greater detail in other sections of the label: Hypersensitivity reactions. [See Warnings and Precautions (5.1) .] The most common adverse reactions (reported in ≥2% of adult and adolescent patients with allergic rhinitis and greater than placebo) were pharyngitis, dry mouth, myalgia, fatigue, somnolence, dysmenorrhea. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Organon LLC, a subsidiary of Organon & Co., at 1-844-674-3200 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. Adults and Adolescents Allergic Rhinitis: In multiple-dose placebo-controlled trials, 2834 patients ages 12 years or older received CLARINEX Tablets at doses of 2.5 mg to 20 mg daily, of whom 1655 patients received the recommended daily dose of 5 mg. In patients receiving 5 mg daily, the rate of adverse events was similar between CLARINEX and placebo-treated patients. The percent of patients who withdrew prematurely due to adverse events was 2.4% in the CLARINEX group and 2.6% in the placebo group. …
Source: FDA drug label, Organon LLC, effective May 17, 2025 (SPL set c671342e-69a2-4ca5-abc2-8166ed4240d4), via openFDA; the full label on DailyMed
What do FAERS reports show?
10,661 reports list desloratadine among the medicines taken, each a report of something that happened, not proof the medicine caused it; 591 are coded as a death and 4,050 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 21 reactions below, 10 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Desloratadine: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions