This year, more than three billion prescriptions will be dispensed - and as many as half will be used improperly.
Preventable medicine-related illnesses cost Americans more than $75 billion each year and can lead to serious harm or even death, according to the Substance Abuse and Mental Health Services Administration.
Kingman pharmacist Andy Chinyere said some people, especially the elderly, do not always take medications properly.
"A doctor will write, 'Take as needed for pain,' but they will take it continuously," Chinyere said.
"Doctors will write 'Take three times a day as needed.' But some take them three times a day every day whether they need them or not, and that's not good.
They could eventually become dependent."
Chinyere said another big problem is people who go to different doctors' offices for prescriptions or to different pharmacies to get the prescriptions filled.
"We can't monitor the medication properly that way," he said.
Jeff Shepherd, another Kingman pharmacist, said over the counter medicines can also be abused.
"Decongestants containing pseudoephedrine have abuse potential.
Boxes were disappearing off the shelves, without a sale," he said.
"We would put out 24 boxes and they would disappear."
Shepherd said pseudoephedrine, used for making "speed," an illegal drug, was kept off store shelves for a while, with customers having to ask a store clerk for medicines containing the drug.
Penny Burdette, a Safeway clerk, said the grocery store still does not put medicines containing pseudoephedrine on shelves because packages disappear.
Shepherd said people with high blood pressure should be especially careful about taking pseudoephedrine and ephedra, a related drug found in some health food supplements.
"Just because it is found over the counter doesn't mean it can't be harmful," he said.
Pharmacist Kris Lehew, whose husband, Dirk, is also a pharmacist, said while most people use prescription medications properly, a significant number do not.
They might take them without a doctor's prescription, use more than prescribed or take them for reasons other than those that the drugs were prescribed for, she said.
"It is more important then ever to receive counseling from the pharmacist when getting a prescription filled, even if you have taken the medicine before," Lehew said.
"We are increasing our health care costs unnecessarily.
A lot of the costs are related to preventable illnesses because of misuse of prescriptions."
She also said some people do not understand how to use prescriptions properly.
"We talk to as many people as we can, answer questions and make sure they know how to use the medicine correctly," she said.
"The role of the pharmacist has changed in recent years.
"We do more than just put pills in bottles.
We are here to give customers all the information they need, and make sure everything is clear to them."
The national survey by the Substance Abuse and Mental Health Services Administration showed that more than 21 million people 12 and older reported having used psychotherapeutic drugs, including stimulants, sedatives, tranquilizers and analgesics available through prescription, for non-medical purposes at some time in their lives.
Stimulants, analgesics, and tranquilizers were the most widely abused drugs that fit this category.