SACRAMENTO, Calif. -- Starting Thursday, allergy sufferers can find the most-prescribed allergy medication available for over-the-counter sales.

Zyrtec is the brand name for cetirizine and is approved to relieve allergy-related sneezing, runny nose, watery eyes, and also, itching from hives.

The U.S. Food and Drug Administration approved it for sale without a prescription in November.

Dr. Rajan Merchant from Woodland Healthcare said it is the same formula as a doctor would prescribe.

"The efficacy is the same; the dosage is the same as the prescription strength. But the reason it is going over the counter is because we have enough safety data that confirms it is usable as an over-the-counter medication," Merchant said.

Merchant estimates Zyrtec will sell for between $20 and $25. That mean some consumers may be paying more now for the drug than they did when it was covered by insurance. But a generic product may soon be available.

Zyrtec does have at least one side effect: It can make users more drowsy than competitor Claritin. However, Merchant said the drowsiness is less prominent than with allergy medication Benedryl.

The drug will be sold as tablets, liquid or chewable tablets.

Zyrtec-D was also approved for sale without a prescription, but it will be kept behind the pharmacy counter because it contains the nasal decongestant pseudoephedrine.