DEAR DR. ROACH: I am a 62-year-old male in generally good health. I have a clot in the popliteal vein in my right knee, and have been taking warfarin and getting periodic blood tests. Typically, the numbers are where my primary care physician wants them. It seems to be taking a long time (eight months) to clear the clot, and I wonder if activities like walking, bike riding, stair climbing or elevating the knee would help or hurt. — R.N.

ANSWER: After a blood clot in the veins of the leg, the blood vessels will slowly “recanalize,” creating a path for the blood through the vein. The blood also will flow around the obstruction through collateral blood vessels. However, the blood vessel remains abnormal to a greater or lesser extent, and is at higher risk for another clot. The venous system has more resistance to flow, so swelling after a blood clot is common. Some physicians are uncomfortable recommending exercise after a clot, but studies have shown that exercise, begun one month after a blood clot, does not worsen swelling or other symptoms. The evidence suggests that exercise won’t hurt and might help.

The booklet on stroke explains why blood clots are deservedly feared by all. Readers can obtain a copy by writing: Dr. Roach — No. 902, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. ROACH: Where can I donate unopened medical equipment and supplies? I hate to discard them, but we no longer have need of them. — D.D.

ANSWER: There probably are organizations in your local community that coordinate the tremendous need for medical supplies for people with no or inadequate insurance and the 6 million tons of surplus medical equipment discarded by U.S. hospitals alone. Goodwill is one such organization that is in many communities. Other nonprofit organizations, such as Project C.U.R.E. and MedShare, help to bridge this gap. You can find more information about them on the Internet.

DEAR DR. ROACH: TV commercials warn of suicide risk from antidepressants. Why would anyone take a drug that is so dangerous? Could recent mass killings also be related to medication use? — V.G.

ANSWER: Suicide is unfortunately too common and little discussed. People with depression are at higher risk for suicide, and certainly those with untreated depression might take their own life. How antidepressant drugs, taken for any purpose (some antidepressants have indications for pain management and tobacco cessation, among others), affect suicide risk is debated. However, the best evidence suggests that children, adolescents and young adults (younger than age 25) are at the highest risk for increasing suicidality when taking antidepressant drugs. This effect is most pronounced in the first few weeks to two months of treatment. The data also suggest that antidepressants have little or no effect on suicide risk in middle-age adults and a have a protective effect in older adults. The Food and Drug Administration has warned physicians who prescribe these medications that patients between 18 and 24 should be informed of the risk of suicide and that clinicians should closely monitor them during initial antidepressant treatment.

There is very little data on violence and antidepressant use. However, what data there is suggests that there is an increase in “hostility events” in people taking antidepressant medicines. This does not mean these drugs are causing the potentially violent behavior: People who are prone to acts of violence often are identified as mentally ill prior to the violent event, and often are treated with psychiatric medication. These medications are prescribed very frequently, and episodes of serious violence, although too common, still are rare compared with the number of people treated.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Health newsletters may be ordered from www.rbmamall.com.