People’s Pharmacy: Stopping eye drops can lead to rebound redness

Q. I have used Visine daily for many years. It soothes my eyes and helps with the redness.

However, I have learned recently that chronic use causes rebound redness if discontinued. I eliminated the drops nearly three weeks ago, but my eyes are still glassy, red and burning. I’m using warm compresses morning and evening. Is there anything else I can do to eliminate the redness?

A. There are several Visine formulations. The Original Redness Relief product contains a decongestant called tetrahydrozoline. That means it constricts blood vessels in the top layer of the eye. This same ingredient is also found in some decongestant nasal sprays.

There are many possible causes of eye redness, including allergens, smoke, fatigue, dry eyes and infection. Repeated use of a topical decongestant, whether in the eye or the nose, can lead to reduced effectiveness. The Visine website warns that “overuse may cause more eye redness.”

As you discovered, stopping abruptly after long-term use can lead to rebound redness (Clinical Optometry, July 23, 2020). Doctors call this “conjunctivitis medicamentosa.” It may take weeks for the redness to clear up. If your eyes don’t get better soon, please check with your eye doctor to rule out infection or some other factor. They may consider a short course of corticosteroid eye drops to help ease the inflammation.

Q. I had a bad case of chickenpox when I was a kid. When I was in my 60s, I had shingles.

I have read that the Shingrix vaccine is very effective. Since I already have had shingles, do I need this vaccine?

A. According to the Centers for Disease Control and Prevention, people can get shingles more than once. The agency urges everyone over age 50 to get two doses of the Shingrix vaccine even if they have had a previous outbreak. The immunization can protect against complications such as long-lasting nerve pain (postherpetic neuralgia) that may follow a shingles attack.

A new study suggests that the varicella zoster virus that causes shingles can reactivate the herpes virus responsible for cold sores (Journal of Alzheimer’s Disease, Aug. 2, 2022). Vaccination against shingles may reduce the risk for this chain of events. That is important because reactivation could be a risk factor for Alzheimer’s disease, so immunization might reduce the likelihood of developing dementia.

Q. You have written about metformin to control blood sugar, but you didn’t cover my experience. For over a year, I suffered through horrendous bouts of vomiting and diarrhea, sometimes as often as once per week. My primary care physician sent me for tests, including a colonoscopy and ultrasound. We found nothing to explain it.

During my latest visit, she told me to begin taking a probiotic and to stop taking metformin.

That was early spring, and I haven’t had a bout of vomiting and diarrhea since! I wanted to share this with your readers.

A. Metformin is the most commonly prescribed medicine for Type 2 diabetes. The most frequent side effects involve the digestive tract. They include heartburn, nausea, stomachache, diarrhea, gas and loss of appetite.

The most serious complication is a buildup of lactic acid. Symptoms such as rapid or irregular heart rate, abdominal pain, fatigue, nausea and low blood pressure could signal this condition.

To learn more about other ways to manage blood sugar, you may wish to consult our eGuide to Preventing and Treating Diabetes. This online resource is available under the Health eGuides tab at www.PeoplesPharmacy.com.

In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of King Features, 628 Virginia Drive, Orlando, Fla., 32803, or email them via their website: www.PeoplesPharmacy.com.