Dear Doctor: What are the best medications for acid reflux? I've tried doxycycline and metronidazole (Flagyl), for H. pylori infections, which made me sick, as well as Prilosec and Pepto-Bismol.

Dear Reader: That's a question asked by many people in the United States, where gastroesophageal reflux disease (GERD) affects an estimated 20 percent of the population. The condition is less common in other parts of the world, although its worldwide incidence is increasing.

Some degree of reflux normally occurs after eating but is not felt. However, when a significant amount of the stomach's acidic contents rises up to the esophagus, it injures the esophageal tissue -- and causes pain. The thick lining of the stomach can handle the acidity; the esophagus cannot. The burning sensation under the breastbone after eating is what people commonly identify as "heartburn." Some people even feel the regurgitation in the back of their throat and mouth. Chronic irritation of the esophagus can cause abnormal cells to form within the esophageal lining, and sometimes these abnormal cells can develop into esophageal cancer. So, although GERD is common, it should not be taken lightly.

The bacteria for which you were treated, Helicobacter pylori, is associated with inflammation and ulcers of the stomach, but its role in GERD is not definite. Some data show that treating H. pylori with antibiotics such as doxycycline and metronidazole reduces GERD in those who have inflammation in the lower portion of the stomach and duodenum. But for you this doesn't seem to have helped.

My first thought in your case has nothing to do with medications. That's because acid reflux is normally prevented by a sphincter between the stomach and the esophagus -- and there are chemicals in our diets that relax this sphincter, allowing the acidic contents to rise up. These chemicals, found in chocolate, alcohol, caffeine, nicotine and mint, can allow the lower esophageal sphincter to loosen, as can, to a lesser degree, onions and garlic. I would look closely at this short list, focusing on the first five, and, if you have not already done so, eliminate them. If these chemicals are causing greater acid reflux, removing them will help relieve your symptoms.

For some people, acid reflux will persist even with dietary changes. When the reflux is severe and enduring enough to damage the esophagus, treatment is necessary. The best treatment is to decrease the acidity of the material coming up. Antacids like calcium carbonate or aluminum hydroxide can help in the short-term, but they do not provide long-term relief; H2 blockers (Zantac, Pepcid, Tagamet) can. They block the histamine-2 receptor in the stomach and thus decrease acidity. They work well for mild to moderate symptoms that are intermittent. However, if used for more than six weeks, they may start losing their effect.

For persistent or severe symptoms, or for severe esophageal inflammation, a proton pump inhibitor (like the Prilosec you took) is necessary; it can be used for up to eight weeks (and sometimes longer if symptoms persist). In addition to the PPI, an H2 blocker taken at bedtime and possibly during the day can boost the relief. Lastly, there's the muscle relaxant Baclofen. Multiple small studies have found that it decreases the frequency of reflux.

So, in other words, keep trying -- and make sure a doctor keeps an eye on your symptoms and the condition of your esophagus.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Hello, dear readers!

We're on the cusp of summer and that means it's our duty as doctors (and mothers) to remind you to please protect yourselves and your family against the sun as you spend more time outdoors, and against the ticks and mosquitos the season always brings. We've written about this before, but if you have any new questions or need clarifications, please drop us a line.

A column in which we addressed the topic of hackers interfering with the proper workings of wireless medical devices, such as pacemakers, got a lot of response. Many readers found it extremely unsettling, and honestly, we're right there with you. The good news, as we said in the column, is that despite how easy television dramas and films make this type of hacking appear, it's actually quite difficult. But if you're worried enough to want to take preventative measures, a letter from a physician in Spokane, Washington, offers an interesting option. His inspiration comes from the range of RFID-blocking products now available to fend off electronic snoops and pickpockets. In this case, the answer is a special vest.

"The vest is lined with metallic mesh to block potential 'pinging' and the theft of personal information," he wrote of a garment he saw in a travel store. "It occurs to me that these would also block 'Bluetooth' and other RF signals being used to hack an internal medical device. It would be simple for a cardiologist to verify this. Simply obtain a vest, have it in the office and when patients come in for modification of settings on an implanted defibrillator or pacemaker, have them wear the vest first, and see if it blocks the modification."

In response to a column about how noise pollution adversely affects health, a reader from Oklahoma asked us to recommend a set of noise-canceling headphones. Because everyone's needs are so different, we suggest scanning the selections from online retailers, like Best Buy, Amazon, Costco and the like. What we find to be helpful about shopping online for items like these are the many reviews posted by fellow shoppers. They can give you a good sense of what each product can (and can't) do, and often answer detailed questions from fellow shoppers, all of which can help you to find the right device for your specific needs.

We'll wrap up with a question stemming from our column about the measles vaccine. A couple who are headed to Paris this fall (lucky you!) ask whether they should get vaccinated for measles. Because you indicate that you both had measles as children, the answer is no. According to guidelines set by the Centers for Disease Control and Prevention, you are considered to be protected from measles if you have either already had the disease or have already received the appropriate doses of the vaccine. Boosters of the measles vaccine are not needed. If you're not sure whether you're protected, you can find out with a simple blood test.

Thank you again for all of your letters. We hope you have a great summer and look forward to continuing this conversation next time.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I am a 64-year-old male in good health, although I have a bit of a gut in the middle. My issue is that I have developed an umbilical hernia that looks like a large "outie." It is not very attractive, but it is not causing any pain or discomfort. What course of action should I take?

Dear Reader: Umbilical hernias, or so-called "belly-button hernias," are quite common. They occur because of tissue weakness at the umbilical ring. The weakness allows the contents within the abdomen to bulge into the opening, thus making an "innie" appear like an "outie." In children with umbilical hernias, the hernia develops because of incomplete closure of the belly-button (umbilicus) at birth. In adults, umbilical hernias develop because of increased pressure within the abdomen that stretches and weakens the tissue (fascia) at the umbilicus. Increased pressure in the abdomen can be caused by obesity, pregnancy or fluid in the belly from diseases such cirrhosis or ovarian cancer.

Umbilical hernias are three times more common in women than in men. The material that typically bulges within a hernia is fat from the abdomen and the lining of the abdominal cavity. In the majority of people, the herniation doesn't hurt. However, when the lining of the abdominal cavity (the omentum) becomes stuck within a hernia, the area can become painful. Even worse is when the small intestine becomes stuck. Called an incarcerated hernia, this compression leads to a loss of blood flow to the intestine, which can cause severe pain, altered bowel movements and possible death of the bowel tissue. The omentum and the intestine are more likely to become entrapped in men. Women more commonly have umbilical hernias that are reducible, meaning the material that pushes into the hernia can easily be moved back into the abdomen.

A small umbilical hernia without symptoms doesn't require treatment. That changes if a hernia causes pain or is not reducible. For a small, symptomatic hernia, a surgeon cuts into the skin and locates the hernia sac. He or she then removes the sac or pushes it back into the abdomen; sutures the surrounding fascial layers together; and thus closes the area of weakness. With a larger hernia, a surgeon will have difficulty bringing together the surrounding fascial layers. This is when he or she will place a mesh over the defect and attach the mesh to the surrounding fascial layers. Unless the hernia is very large (more than 9 centimeters in size), a surgically repaired hernia is unlikely to recur or cause pain.

Because of the lack of symptoms from your hernia, you're unlikely to need surgical treatment. But you should be on the alert for pain in the umbilical area and for difficulty pushing the hernia back in to the abdomen. Either problem is a sign that surgery might be needed.

Also, you might be able to decrease pressure on the abdomen by decreasing your "gut in the middle." Improving your diet by cutting back on sugar, exercising and losing weight will put less pressure upon the hernia and may decrease the likelihood of ever needing hernia surgery.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)