Safe alternatives exist for DEET insect repellent

August 26, 2007 at 2:00a.m.

Q. A few months ago, I sprayed insect repellent containing DEET on my legs to keep mosquitoes away. Then I lay down on the grass on my stomach to pull weeds out of my pond. Two days later, the grass where my legs had been was dead. None of the other grass was.

If this product kills grass, what does it do to skin?

A. DEET was developed for the U.S. Army and has been used by the public for more than 50 years. Skin irritation has been reported as the most common side effect. There have been some reports of neurological side effects, including seizures, particularly at high concentrations.

DEET is the most effective mosquito repellent on the market. There are some effective alternatives, however. They include picaridin (Avon Skin So Soft Bug Guard, Cutter Advanced, OFF! FamilyCare Clean Feel) and oil of lemon eucalyptus (Repel Lemon Eucalyptus).

Q. Is there a link between acid-suppressing drugs and forgetfulness? My mother has been on Tagamet, Zantac and now Prilosec for many years, and her forgetfulness seems unusual.

A. A recent study reported an association between the use of acid-suppressing drugs such as Pepcid (famotidine), Tagamet (cimetidine) and Zantac (ranitidine) and declining mental function. The subjects were older blacks in Indianapolis (Journal of the American Geriatrics Society, August 2007).

One possible explanation for such problems might be depletion of vitamin B-12. This nutrient is essential for normal mental functioning. Vitamin B-12 is absorbed best when there is acid in the stomach. Long-term use of acid-suppressors might make it harder to maintain adequate B-12 levels.

Q. I had my thyroid removed due to cancer more than a decade ago. Since then I have been on Synthroid. The past few years I was switched to Levoxyl.

My doctor has lowered my dosage twice in the past six months. Since then I have noticed the following changes: from reduced libido to NO libido, elevated cholesterol, fatigue and brittle nails splitting down the middle. I’ve lost the outer third of my eyebrows. Is there any way to reverse these symptoms?

A. Talk with your doctor about your symptoms immediately. They suggest you might be getting too little thyroid hormone. Perhaps the dose of your medicine was lowered too much. Other readers report that when they are switched from one thyroid formulation to another, the dose must be adjusted carefully.

We are sending you our Guide to Thyroid Hormones, with discussions of diagnostic difficulties and tests as well as various thyroid hormones.

Q. I’ve been troubled with irregularity most of my life until I discovered Fiber One cereal. I take it with me everywhere — on cruises, to Europe, even to the hospital. Fiber One bars come in handy when there’s no milk supply available.

It’s the only remedy that’s ever worked for me. I can’t stand liquid Metamucil, so I tried the capsules, with no results. Benefiber also did nothing for me, so I’m a Fiber One fan forever.

A. Thanks for sharing your constipation solution.

XIn their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of this newspaper or e-mail them via their Web site: www.Peoples-Pharmacy.com.