DEAR DR. ROACH: The literature on Avodart use for benign prostatic hyperplasia mentions that only 1 percent of men taking it experience sexual difficulties. Are there ongoing or recent studies on Avodart use that would explain diminished climax response in an otherwise healthy senior adult male? As an alternative, what is the percent of TURP patients who have significant loss of sexual performance and/or incontinence? — Anon.

ANSWER: Avodart (dutasteride), like Proscar (finasteride), is effective for many men with enlarged prostate symptoms, but it certainly can have side effects. I have seen many men with sexual function problems (including erection, libido and ejaculation), and think the incidence is a lot higher than 1 percent. Most literature I found stated a 4 to 6 percent risk of sexual dysfunction, but one trial found it as high as 13.8 percent.

Prostate surgery — transurethral resection of the prostate (TURP) — also can have sexual and urinary side effects. Depending on the type of TURP procedure, between 17 and 40 percent of men reported a worsening in sexual function after surgery. In most cases, the differences were small, with less than 10 percent of men having new-onset erectile dysfunction. However, retrograde ejaculation (backward into the bladder) can happen in up to two-thirds of men. A different study on what is best (men were randomized to surgery, medication and laser procedure) found that surgery was best for preserving sexual function.

DEAR DR. ROACH: In a recent column regarding turmeric and its active ingredient, curcumin, you discussed possibly taking it alongside other medications.

Shouldn’t you have warned the reader to be very careful if on blood thinners, such as aspirin? A friend taking turmeric capsules had to be off medications for two weeks before major surgery, which was a surprise to him. When I found out he was having surgery, I asked whether the surgeon knew he was on turmeric. He had not told the surgeon, because it was just a supplement. I am on Aggrenox and research every supplement before I take it.

People take supplements that friends recommend without researching their side effects and interactions. — W.G.

ANSWER: Turmeric can, in theory, increase the effects of anticoagulants like aspirin and Aggrenox (which is aspirin plus dipyridamole, a different antiplatelet agent). I found two studies that looked at laboratory interactions. However, there haven’t been reports of clinically significant bleeding. It seems your friend’s surgeon was being extremely cautious.

Your overall point, though, is extremely important: Supplements can interact with medications. If you are taking medicines that have multiple interactions, such as warfarin (Coumadin), it’s great to do the research yourself, but you absolutely should discuss any additional medications or supplements with your doctor.

DEAR DR. ROACH: Do you know any exercises I can do in the pool to strengthen my abdominal and back muscles? — J.G.

ANSWER: Most exercises in the pool will work both abdominal and back muscles. However, if you really want a good experience, go to a water exercise class at your local pool and get a trained instructor to help teach you exercises to do.

READERS: The booklet on vertigo explains this disruptive condition in detail and outlines its treatment. Readers can order a copy by writing: Dr. Roach — No. 801, 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.

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.