There is no question that prescription drugs have a major place in treating and curing diseases and helping to keep chronic conditions under control. Yet there are some important factors that anyone taking prescription drugs should understand. One of these is the fact that we tend to become more sensitive to a drug's effects as we get older. As we age, our metabolism slows down, as do our digestive system, liver and kidney functions. We lose muscle tissue and gain fat tissue. What does this have to do with your medication? It affects how a drug will be absorbed into your bloodstream, how it will react in your various organs, and how quickly it will be eliminated. All of that affects how well it will work for you.

• If you've been taking a particular prescription medicine for years, and you notice it's not having the desired effect or not affecting you the way it used to, ask your doctor about adjusting the dosage.

• If you start a new medication, and it doesn't seem to do what the doctor or pharmacist has told you it will do, call your doctor and ask about adjusting the dosage. With new medications in older people, the 'rule of thumb' is 'start low and go slow' - so you may need a higher dose than your doctor first prescribed.

• If you experience any side effects - such as dizziness, constipation, upset stomach, sleep changes, diarrhea, incontinence, blurred vision, mood changes, or a rash - after taking a drug, call your doctor right away. Any of these can be caused by a drug and can be eliminated by trying a different dosage or different drug. Don't just stop taking the medication without talking to your doctor or pharmacist.