Ask The Doctors: November 2010
Q. I’ve been experiencing knee pain and I’d like to see my doctor about the possibility of arthritis. What’s best for determining a diagnosis of arthritis—an X-ray or MRI?
Most often, knee arthritis can be detected with X-rays, and they should be obtained before MRI (magnetic resonance imaging) is considered.
In patients with rheumatoid arthritis, an MRI may allow earlier detection of bone erosion than X-rays, but this information may not change your treatment plan. One study found that MRI did not provide any information that could not have been obtained by X-rays, and researchers concluded that in most patients MRI is unnecessary.
If your physician suspects a more serious or uncommon condition, he or she may order an MRI to confirm or rule out the condition.
Is it true that testosterone injections can help men over 65 retain their coordination and balance?
Testosterone therapy has been suggested to increase muscle mass, sharpen memory and concentration, boost libido, and increase energy levels. Despite its possibilities, however, it is not a miraculous anti-aging formula.
Scientific studies on the effects of testosterone therapy for older men have had mixed results. Although heightened testosterone levels are associated with increased muscle mass, no study has shown that this results in improved coordination and balance.
Testosterone therapy is not without risks, including allergic reactions, interactions with other medications, prostate enlargement, fluctuations in cholesterol levels, excessive production of red blood cells (which can increase your risk of heart disease), sleep disturbance, and cognitive changes such as confusion, mood swings, memory loss, and loss of concentration.
The worst effect is that administration of external testosterone may make your body unable to produce testosterone naturally. Talk with your physician about testing your testosterone level to determine if any type of testosterone therapy is indicated.
What does it mean when a drug is prescribed for "off-label use"? Is this legal?
Before a drug is approved in the U.S., it must be proven that it effectively and safely treats a specific medical condition. When this has been proven in clinical trials, the U.S. Food and Drug Administration (FDA) and the drug manufacturer create the drug’s label, which includes specific information about what disease or condition the drug is approved to treat, how it is to be given, and in what dosages.
"Off-label use" means that the drug is prescribed for a different medical condition, or in a different form (pills or injection, for example), or in a different dosage. Off-label use is legal in the U.S. and is common for many medicines for which new uses have been found, with adequate medical evidence to support these uses.
Heart medicines, antipsychotics, and antibiotics are commonly prescribed off-label. Beta blockers, for example, were first approved for treating high blood pressure but have since been determined to be effective for treating heart failure and migraines. Some medicines designed to treat depression also are used to treat chronic pain.
On the other hand, in off-label use the risks of a medication’s side effects may not be known when it is used for an unapproved condition. If your doctor suggests an off-label use, ask if there are studies to support this use, if this off-label use is likely to work better than the approved use of another drug, and what the risks and benefits may be.