Counterfeit drugs, spoiled pills and unsupervised treatments are a few of the risks of using online pharmacies

With the rise of on-demand delivery, prescription medicine joins the countless list of items that can be ordered online with the click of a button.

But when it comes to purchasing medicine online, the convenience does not outweigh the risks, says Karl Fiebelkorn, senior associate dean for student, professional and community affairs at the University at Buffalo School of Pharmacy and Pharmaceutical Sciences.

Only 3 percent of online pharmacies are safe and legal, according to the United States Food and Drug Administration (FDA). And the World Health Organization reports that half of medicines sold online are counterfeit, sometimes containing substances such as drywall, lead or boric acid.

Yet online pharmacies fill 18 percent of the nation's prescriptions, according to data from the 2015 Pharmacy Satisfaction PULSE survey by pharmaceutical manufacturer Boehringer Ingelheim.

After sending in their prescriptions and insurance information, patients receive their medication in the mail, often at what they believe are lower prices, says Fiebelkorn.

However, data from the National Community Pharmacy Association found the notion is untrue, as community pharmacies may offer comparable prices and are more likely to substitute lower-cost generic drugs.

Patients who look to cut health care costs by shopping online for their medicine run the risk of giving their local pharmacist a fragmented picture of their drug regimen when they need a drug for an acute condition, he says.

"Your local pharmacist monitors your medication patterns for adherence and dangerous drug interactions, and works with your primary health care provider to make sure you obtain the medication that is right for you and your budget," says Fiebelkorn. "These highly-trained pharmacists are there to discuss your medications face-to-face."

Patients will not receive the same experience when purchasing medications through mail-order pharmacies.

Although many mail-order medicine retailers list contact information for staff pharmacists, patients may experience common customer service issues such as long hold times and repeated transfers to have issues addressed – problems that could be solved in minutes at a community pharmacy, he says.

Local pharmacists, he adds, also support patients during their transition from the hospital to their home by reconciling medication, which helps reduce the likelihood of hospital readmission after discharge.

Transportation poses other risks as well. Extended exposure to weather extremes can leave medicine ineffective, says Fiebelkorn.

Just like food, extremely cold temperatures or sweltering heat can freeze or spoil even tablet forms of drugs that have sat inside a mailbox or delivery truck for a few hours. Shipment delays can also cause patients to run out of their medication.

"Several pharmacists have told me that patients come to their pharmacy because the medication they ordered from an online pharmacy is delayed or never arrived," says Fiebelkorn, adding that most mail-order retailers are located outside of New York.

"During bouts of severe weather where the postal service did not run, it was the independent pharmacies who traveled to deliver needed medications to their patients."

Fiebelkorn suggests consumers check the National Association of Boards of Pharmacy's list of Verified-Internet Pharmacy Practice Sites before dealing with an online pharmacy to ensure the retailer meets national standards.