Question: I forgot to ask my doctor a question about the drug he prescribed for me. Is it OK to ask the pharmacist when I get the prescription filled?

Answer: Few people realize that there is an almost limitless supply of free advice and information from the pharmacist behind the counter at your nearest chain or independent pharmacy. Since the 1990s, pharmacists will have studied at a university for six years, focusing on anatomy, physiology, pharmacology, pharmacotherapeutics and pharmaceutics. And they will have learned how to provide you with information about your drugs and to keep records of them. They must pass state board exams before they can get a license.

Anatomy is about the muscles, bones, arteries, veins, internal organs, and physiology is how those parts work together, such as how the lungs get oxygen into the blood. Pharmacology is the study of how drugs work in the body, usually by blocking some substance or combining with some enzymes or certain cells.  Pharmacotherapeutics is how drugs work on certain conditions, and pharmaceutics is the study of how the body  processes drugs.

If a pharmacy is open, most states require that there be a licensed pharmacist on duty. There is almost never any fee or charge for a consultation, nor is an appointment needed. The pharmacist is the person to ask when you don't feel so well after starting a new medicine, or when you have questions about how other medicines and supplements you're taking may interact with that new medicine.

We want to think all drugs are safe, but that is not always the case. Some people are allergic to some medicines, and two drugs prescribed by different doctors may combine in the body to make both inactive.  Pharmacists can usually sort these things out fairly rapidly.

Pharmacists can often recommend over-the-counter drugs, and when they sense that something serious is happening, they can suggest a good nearby physician or clinic. Many pharmacists have gotten certified to administer immunizations such as for flu, pneumonia, and herpes zoster (shingles). It is faster, cheaper and more convenient to have a pharmacist instead of a physician administer vaccines.

More recently, pharmacists are conducting Medication Therapy Management (MTM) for patients. Patients make an appointment for a 30- to 45-minute session with the pharmacist and bring all of their medicines. The pharmacist discusses each medicine with the patient with the goal of streamlining that patient's total therapy.

You may not be aware of it, but pharmacists are required to maintain their competency by earning about 30 hours of approved continuing education every year. This can be from lectures or journals or even online, and they must receive a passing grade to get the credit. These requirements vary only slightly from state to state.

So, even if your pharmacist graduated in 1975, that person should know about the newer categories of drugs that have entered the market since then.

Medicines are powerful.  Let your pharmacist help you use them safely.

Albert I. Wertheimer, Ph.D., professor of pharmacy administration at Temple University School of Pharmacy, and Patricia J. Bush, Ph.D., professor emeritus at Georgetown University School of Medicine, are co-authors of "Your Drugs and Sex: How Prescription and Non-Prescription Drugs Can Affect Your Sex Life."