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Drug Profile

Do NOT stop taking this or any drug without the advice of your physician. Some drugs can cause severe adverse effects when they are stopped suddenly.

Do Not Use [what does this mean?]
Generic drug name: desloratadine (des lor AT a dine)
Brand name(s): CLARINEX
GENERIC: available FAMILY: Antihistamines
Find the drug label by searching at DailyMed.

Alternative Treatment [top]

Safety Warnings For This Drug [top]

Non-Drug Approaches to Allergies

Avoid exposure to things that trigger your allergies or asthma, such as animals, bedding, chemicals, cosmetics, drugs, dust, mold, foods, pollens, or smoke. Wearing a mask reduces inhalation of drugs, pollens, and smoke. Many people with mildly red, itching eyes require no treatment. Cold compresses to the eyes may prove helpful. Using eye drops with vasoconstrictors whitens eyes for a while, but rebound redness can occur. Misuse of vasoconstrictors sets up a vicious cycle.

Product Warnings

Ask a doctor or pharmacist before use if you are taking antibiotics.

When using this product, tiredness, drowsiness or dizziness may occur. Be careful driving or operating machinery.

Stop using and ask a doctor if symptoms get worse, diarrhea lasts more than two days or you get abdominal swelling or bulging. These may be signs of a serious condition.

If pregnant or breast-feeding, ask a health care professional before use.

Older adults are especially sensitive to the harmful anticholinergic effects of this drug. Drugs in this family should not be used unless absolutely necessary.

Mental Effects: confusion, delirium, short-term memory problems, disorientation and impaired attention.

Physical Effects: dry mouth, constipation, difficulty urinating (especially for a man with an enlarged prostate), blurred vision, decreased sweating with increased body temperature, sexual dysfunction and worsening of glaucoma.

Facts About This Drug [top]

Desloratadine was Schering-Plough’s replacement for its $3 billion a year antihistamine loratadine (CLARITIN). Desloratadine was only technically a new drug when it was approved by the Food and Drug Administration (FDA) in 2001; patients who had been taking the older loratadine since it was approved in 1994 had been producing desloratadine with each dose of loratadine. The body rapidly converts (or metabolizes) loratadine into desloratadine, which is the active substance that provides most of...

Desloratadine was Schering-Plough’s replacement for its $3 billion a year antihistamine loratadine (CLARITIN). Desloratadine was only technically a new drug when it was approved by the Food and Drug Administration (FDA) in 2001; patients who had been taking the older loratadine since it was approved in 1994 had been producing desloratadine with each dose of loratadine. The body rapidly converts (or metabolizes) loratadine into desloratadine, which is the active substance that provides most of the drug’s antihistamine effects.[1] Thus, desloratadine is referred to as an active metabolite of loratadine.

Desloratadine’s manufacturer abused the basic intent of U.S. patent law (which is intended to reward ingenuity and originality) in order to get a patent for desloratadine. Then they took advantage of the FDA’s 40-year-old legal standard for approving new drugs, which does not require new drugs to be better than older ones, to get the drug approved.

Desloratadine is available only by prescription, whereas loratadine is only available over-the-counter.

There are no studies or data to show that loratadine and desloratadine are clinically different. The company submitted four clinical trials to the FDA comparing various doses of desloratadine with a placebo for support of the drug’s approval. Only in two of these studies was the approved 5-milligram-per-day dosage found to be effective. However, this was sufficient under current law to justify the drug’s approval.

The FDA medical officer’s review indicates that Schering-Plough was trying to convince the agency that desloratadine’s onset of effect was between one and two hours. The medical officer concluded, “There is adequate data to support a claim for effectiveness of 5 mg of [desloratadine] beginning within two days of initiating treatment.”[2]

In December 2002, the European Medicines Agency added a warning to the professional product labeling of drugs containing desloratadine indicating that they should not be used during pregnancy. Desloratadine and loratadine have been linked to a fetal malformation known as hypospadias (penile malformation).[3]

Overall, desloratadine is an unremarkable antihistamine, as is loratadine. The nonprescription antihistamines such as generic chlorpheniramine (CHLOR-TRIMETON) are effective, perhaps equally or more so than desloratadine. The drowsiness that some people may experience when using generic chlorpheniramine can be avoided by starting with a low dose and slowly working up to a dose that relieves symptoms without sedation. This can save a substantial amount of money.

In 2018, researchers in Sweden published an article describing reports of depression associated with the use of desloratadine.[4]

last reviewed February 28, 2021