Desloratadine belongs to a group of medications known as antihistamines, specifically the class known as H1-receptor antagonists. During an allergic reaction, the body produces a chemical called histamine, which causes allergy symptoms such as hives, runny nose, sneezing, itchy throat, congestion, and itchy watery eyes. Desloratadine works by blocking the action of histamine in the body.

This medication is used to relieve the symptoms of seasonal and year-round allergies including nasal congestion, sneezing, runny nose, itchy nose, itchy palate, coughing, and itchy watery red eyes. It is also used to relieve the symptoms of allergic skin conditions (e.g., chronic idiopathic urticaria) such as skin itch and hives. Desloratadine usually starts to work within 75 minutes and lasts for 24 hours.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

Tablets: The usual recommended dose of desloratadine tablets for adults and children 12 years of age and older is 5 mg once daily. It may be taken with or without food.

Syrup: The usual recommended dose of desloratadine syrup for adults and children 12 years of age and older is 10 mL (5 mg) once daily. For children 6 to 11 years of age, the usual recommended dose is 5 mL (2.5 mg) once daily. For children 2 to 5 years of age, the usual recommended dose is 2.5 mL (1.25 mg) once daily. It may be taken with or without food. Children between 2 to 12 years of age should not take this medication for longer than 14 days unless recommended by a doctor.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from moisture, and keep it out of the reach of children.

Tablet
Each blue, round, film-coated tablet for immediate release contains 5 mg of desloratadine. Nonmedicinal ingredients: carnauba wax, cornstarch, dibasic calcium phosphate dihydrate, FD&C Blue No. 2 Lake, hydroxypropyl methylcellulose, lactose monohydrate, microcrystalline cellulose, polyethylene glycol, talc, titanium dioxide, and white beeswax.

Syrup
Each mL of clear, orange liquid with bubble gum flavouring, contains 0.5 mg of desloratadine. Nonmedicinal ingredients: bubble gum flavour, citric acid anhydrous, disodium edetate, FD&C Yellow No. 6, propylene glycol, purified water, sodium benzoate, sodium citrate dihydrate, sorbitol solution, and sucrose.

Do not take this medication if you are allergic to desloratadine or any ingredients of the medication.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• dry mouth, nose, or throat
• fatigue
• headache
• increased appetite

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• fever
• pounding, fast, or irregular heartbeat
• restlessness with increased body movement
• symptoms of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• symptoms of a urinary tract infection (e.g., pain when urinating, urinating more often than usual, low back or flank pain)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• seizures
• symptoms of a severe allergic reaction (e.g., difficulty breathing, hives, or swelling of the mouth or throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Drowsiness/reduced alertness: At the recommended dose, desloratadine is not expected to make you drowsy. Very rarely, desloratadine may cause drowsiness, affecting your ability to drive or operate machinery. Avoid driving, operating machinery, or performing other potentially hazardous tasks until you have determined how you are affected by this medication.

Kidney function: If you have severely reduced kidney function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: If you have severely reduced liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Seizures: Seizures have been reported by people taking desloratadine. In particular, young children may be more likely to develop new seizures. If you have a history of epilepsy or medical conditions that increase the risk of seizures, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are breast-feeding and are taking desloratadine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using desloratadine tablets have not been established for children under 12 years of age. The safety and effectiveness of using desloratadine syrup have not been established for children under 2 years of age.

There may be an interaction between desloratadine any of the following:

• alcohol
• other antihistamines (e.g., azelastine, cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine)
• antipsychotics (e.g., cariprazine, chlorpromazine, clozapine, haloperidol, methotrimeprazine, olanzapine, quetiapine, risperidone)
• barbiturates (e.g., butalbital, phenobarbital)
• benzodiazepines (e.g., alprazolam, diazepam, lorazepam)
• betahistine
• brimonidine
• buprenorphine
• cannabis
• chloral hydrate
• clopidogrel
• deferasirox
• dimenhydrinate
• diphenoxylate
• efavirenz
• entacapone
• esketamine
• flibanserin
• flunarizine
• gemfibrozil
• general anesthetics (medications used to put people to sleep before surgery)
• hyaluronidase
• ketoconazole
• leflunomide
• lemborexant
• lumacaftor and ivacaftor
• metoclopramide
• mifepristone
• minocycline
• mirtazapine
• muscle relaxants (e.g., cyclobenzaprine, methocarbamol, orphenadrine)
• narcotic pain relievers (e.g., codeine, fentanyl, morphine, oxycodone, tapentadol, tramadol)
• olopatadine
• perampanel
• pitolisant
• pomalidomide
• pramipexole
• ropinirole
• rotigotine
• scopolamine
• selpercatinib
• seizure medications (e.g., clobazam, levetiracetam, phenobarbital, primidone, topiramate, valproic acid)
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
• sleeping medications (e.g., zolpidem, zopiclone)
• sodium oxybate
• teriflunomide
• tetrabenazine
• thalidomide
• tizanidine
• trazodone
• tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
• zolpidem
• zopiclone

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.