Voltaren Gel, a new topical prescription drug for joint pain

I read about a topical form of diclofenac called Voltaren Gel. It is supposed to be applied to the skin over painful joints such as the knee.

Americans are familiar with oral nonsteroidal anti-inflammatory drugs such as celecoxib (Celebrex), diclofenac (Cataflam, Voltaren), ibuprofen (Advil, Motrin), indomethacin (Indocin), meloxicam (Mobic) and naproxen (Aleve, Anaprox, Naprosyn). These can relieve arthritis pain, but may cause increased blood pressure, ringing in the ears, blood clots, stomach upset and bleeding ulcers.

Applying the medication directly on the painful joint may reduce the dose needed to get relief and reduce the likelihood of serious side effects. Voltaren Gel requires a prescription.

I take Coumadin to prevent blood clots and have paid attention to potential interactions with food and other medicine. I read that a full adult dose of Pepto-Bismol is the equivalent of eight aspirins. How serious is this interaction?

The maximum daily dose of Pepto-Bismol contains 2,080 mg of salicylate. This aspirin-like drug could well interact with the blood thinner warfarin (Coumadin), increasing the risk for bleeding. Symptoms include bruises, dark stool, nosebleeds or bleeding gums.

People who use arthritis rubs containing methyl salicylate (oil of wintergreen) also may risk this interaction. Arthritis Formula Bengay, Icy Hot Cream, Mentholatum Deep Heating and Thera-Gesic all contain methyl salicylate.

Reach Joe Graedon, a pharmacologist, and Teresa Graedon, an expert in medical anthropology and nutrition, at www.peoplespharmacy.com or in care of this newspaper.