ST. CHARLES COUNTY • Pharmacies across St. Charles County on Tuesday began requiring prescriptions for cold and allergy medications containing pseudoephedrine, the key ingredient in the illicit manufacture of methamphetamine.

Spokesmen for several stores said it was too soon to gauge the impact of the county's prescription ordinance on people who use affected items such as Sudafed.

Meanwhile, the offices of three St. Charles County physicians who specialize in allergies and asthma said they have been getting prescription requests in recent weeks from patients aware of the law.

The measure was passed by the County Council July 25 in an attempt to reduce meth labs.

Andy Palans, owner of Wharf Health Mart in O'Fallon, Mo., said only one customer stopped by his store by midafternoon Tuesday asking to buy an affected medication.

Palans said the man didn't realize that a prescription was now required. "He said I guess I might have to take a trip to Chesterfield" where there is no prescription rule.

Alan Honerkamp, owner of a Medicine Shoppe store in St. Charles, months ago had voluntarily restricted sales of such medications to regular customers. In recent weeks, he said, he had been informing them about the new prescription law.

He said some were contacting their physicians to obtain one while others "probably will try another product if that's an option."

At a Walgreens store in St. Charles, pseudoephedrine products formerly on a shelf behind the pharmacy area's cash register were no longer in evidence Tuesday.

An employee interviewed around noon said four or five people by that time had tried unsuccessfully to buy an affected medication.

More than 45 local governments across Missouri have such laws but St. Charles County is by far the largest in population.

Lisa Schneider, a nurse at the practice of Drs. Jacqueline Reiss and Rand Dankner in St. Peters, said she has handled inquiries from about 25 patients in the last three weeks about prescriptions for the medications involved.

"A lot of our patients have asked, 'What am I supposed to do?' " Schneider said.

Angie Hayden, a nurse in Dr. Richard Cannon's office in St. Charles, said she'd gotten five or six inquiries recently.

Both offices said patients who see their doctor regularly typically get a prescription by telephone while others with less contact are asked to make an appointment with the doctor.

A leading anti-meth advocate, Sgt. Jason Grellner of the Franklin County Sheriff's Department, said 56 pharmacies are affected by the St. Charles County law. He said that means about 500 of 1,200 pharmacies statewide now have prescription requirements, either because of local laws or voluntary participation.