Dear Dr. Gott: I have a heart condition and take both Plavix to prevent blood clots and Prilosec for stomach acid. I was recently informed there are new reports out that advise me not to take my Prilosec. What is this all about, and what are my options?

Dear reader: Plavix is prescribed by physicians to prevent blood clots that could lead to heart attack or stroke in some patients. Prilosec (omeprazole) reduces the incidence of excess stomach acid. In November 2009, the Food and Drug Administration issued a warning to patients not to take one if you are on the other.

New research suggests that when Prilosec and Plavix are taken, the ability to block platelet anticlotting may be reduced by almost 50 percent. Plavix alone isn't capable of producing an anticlotting effect until it is metabolised or converted into an active form with the assistance of the liver enzyme CYP2C19.

With the addition of Prilosec, this liver enzyme is blocked, substantially reducing the potential effectiveness of the Plavix. Once the possible interaction was noted, the FDA requested additional studies from the manufacturer that supported the existence of a significant interaction that could negatively impact a person's health.

As a result, the Plavix label has been updated and now includes warnings regarding the use of Prilosec and other drugs that block the liver enzyme. It is unknown how other proton-pump inhibitors (PPIs) may interfere, but the recommendation is that Nexium, Tagamet and Tagamet HB, Diflucan, Nizoral, VFEND, Intelence, Felbatol, Prozac, Sarafem, Symbyax, Luvox and Ticlid also not be taken with Plavix because of the potential for similar interactions.

Any patient prescribed Plavix who needs medication to control stomach acid should speak with his or her physician for a recommendation of possible substitutes, such as Zantac, Pepcid, Axid and others that do not inhibit the CYP2C19 enzyme.

So make a telephone call now or set up an early appointment with your doctor to resolve the issue.

To provide related information, I am sending you a copy of my Health Report "Consumer Tips on Medicine."

Other readers who would like a copy should send a self-addressed stamped No. 10 envelope and a $2 check or money order to Newsletter, P.O. Box 167, Wickliffe, OH 44092, or download an order blank from my web site, www.AskDrGottMD.com. Be sure to mention the title.

Dear Dr. Gott: I have Parkinson's disease and have a great deal of saliva. I take two kinds of drugs — ropinirole and carbidopa/levodopa — and wonder if they are necessary.

Dear reader: Parkinson's is a neurological disorder with a myriad of symptoms, including fatigue, malaise, depression, memory loss, cramped handwriting, tremor, rigidity, gait abnormalities, lack of facial expression and sense of smell, and more. Postural instability develops as the disease progresses.

Excess saliva is uncommon, but each person experiences different symptoms, so I won't unequivocally dismiss any involvement with your diagnosis. Current research indicates that symptoms of Parkinson's disease are related to depletion or low levels of dopamine in the brain. Ropinirole is a central-nervous-system agent with some of the same effects as dopamine. Carbidopa and levodopa work in combination.

Carbidopa helps to prevent the breakdown of levodopa before it reaches the brain. Then the levodopa kicks in and converts to dopamine once it gets there. You may have been placed on the ropinirole in addition to your carbidopa/levodopa because the combination drug alone did not control your Parkinson's symptoms satisfactorily.

I urge you to discuss any concerns or questions you may have regarding your treatment with the prescribing physician. You should also be under the care of a neurologist familiar with treating Parkinson's disease.

Dr. Peter Gott is a retired physician and the author of the book "Dr. Gott's No Flour, No Sugar Diet," available at most chain and independent bookstores, and the recently published "Dr. Gott's No Flour, No Sugar Cookbook." Write directly to Dr. Gott c/o United Media, 200 Madison Ave., 4th fl., New York, NY 10016.