A new oral medication to treat ragweed allergies has been approved by the Food and Drug administration, the agency announced April 17.

The medication, called Ragwitek (a drug from Merck and Co.), is a tablet taken once a day by placing it under the tongue, where it dissolves. It is approved for people who are allergic to pollen from the plant short ragweed (Ambrosia artemisiifolia).

Patients should start taking the medication 12 weeks before ragweed season, and use it throughout the season, the FDA said. The first dose should be taken in a doctor's office in case the patient has an allergic reaction to the drug, which contains extract from the short ragweed plant itself. [9 Weirdest Allergies]

The drug is an alternative to allergy shots or medications that relieve allergy symptoms, the FDA said.

People with ragweed pollen allergies, one of the most common seasonal allergies, may have symptoms such as sneezing, a runny nose, nasal congestion, and itchy and watery eyes, especially during the late summer and early fall.

In a study of 1,700 adults, the most common side effects of the drug were itching and irritation in the mouth, ears and throat. During one allergy season, people who took Ragwitek had a 26 percent reduction in symptoms and the need for allergy medications compared with those who received a placebo, the FDA said.

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