Dear Doctor: My wife overindulged on her birthday and wound up with a pretty fierce hangover -- headache, nausea, brain fog, the works. She got so much weird advice that it got us to wondering, what exactly is a hangover? Are there any remedies that actually work?

Dear Reader: Your question is one for the ages -- literally. References to the unique state of distress we call a hangover date back thousands of years. So does the quest for a cure. Yet despite the best efforts of modern science, the cause of a hangover -- as well as a remedy -- remains unclear.

Let’s start with what we do know. A hangover occurs when you drink too much alcohol. For some, a few glasses of wine can lead to profound regret the morning after. For others, getting a hangover takes a night of excessive drinking of hard liquor. No matter the amount of alcohol, the symptoms remain the same. These include the headache, nausea and cognitive issues that your wife suffered from, as well as dry mouth, thirst, fatigue, dizziness, vertigo, diarrhea, tremors, disturbed sleep, rapid heartbeat, excessive perspiration, anxiety, low mood and sensitivity to light and sound.

Research suggests that genetics play a role in how much you can drink before you’ve earned yourself a hangover. So do a person’s age, sex and physical health; the state of their immune system; and how quickly they drink. The specific type of alcohol may also be a factor. Darker-colored drinks -- such as bourbon, dark beer and red wine -- contain higher concentrations of compounds known as congeners. The body metabolizes these into toxic substances such as formaldehyde and formic acid, which can add to hangover misery.

Dehydration was long considered a prime culprit in hangover symptoms, but recent research has found no difference in electrolyte levels among people who are hung over and those who are not. Although a toxic compound known as acetaldehyde, produced when the body breaks down ethanol, had been implicated in hangover misery, more recent research now points to the role of cytokines. These are small proteins associated with inflammation, which the immune system uses for signaling. The theory is that drinking triggers the release of cytokines, which in turn unleash the full fury of the immune system.

As for how to cure a hangover, science hasn’t gotten that far. The best you can do is manage the symptoms for the eight to 24 hours it takes for a hangover to play out. First, skip hair-of-the-dog therapy. More alcohol may give a temporary boost, but soon enough leads to the throes of even more misery. Instead, drink plenty of water, eat complex carbs to boost low blood sugar and fend off nausea, use antacids if needed for stomach upset, and get some sleep. Aspirin and other non-steroidal anti-inflammatories can help with headache, but can also irritate the stomach. Never take Tylenol during or right after drinking, as it can cause liver damage when mixed with alcohol. No one who has ever had a hangover wants to hear this, but the only certain cure is time.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I keep reading about stents, and how it turns out they’re no better for blocked arteries than heart meds. How does something like that get decided?

Dear Reader: You’re referring to the findings from a large international study that evaluated various medical interventions for patients with blocked coronary arteries.

Before we get into the study, we should first talk about coronary artery disease. This is a condition in which the vessels that supply the heart muscle with oxygen-rich blood become blocked. A substance called plaque -- which is made up of cholesterol, calcium, fat and other cells -- collects along the inner lining of the arteries and causes them to narrow. This limits the blood flow in the arteries, and, in some cases, can cut it off entirely. When the flow of oxygen-rich blood to the heart slows or stops, the results can range from chest pain, irregular heartbeat and shortness of breath, to heart attack, to an increased risk of stroke. Bits of the hardened plaque can also break free and cause blood clots, which can also limit or stop blood flow.

Coronary artery disease is the most common type of heart disease in the United States. According to the Centers for Disease Control and Prevention, it accounts for more than 370,000 deaths each year. It’s a serious problem, and researchers have spent decades looking for solutions. These include bypass surgery and the use of stent intervention, which were evaluated in the study.

In bypass surgery, a surgeon uses a blood vessel taken from another part of the patient’s body to route the flow of blood around the blocked artery. A less invasive option is the stent, which is a tiny mesh tube implanted into the artery via a long, flexible tube known as a catheter. The surgeon inserts the catheter into an artery in the arm or groin and then, with the help of a special X-ray machine, guides it through the blood vessels until it reaches the desired area. Once in place, the rigid stent physically opens and supports the artery walls, which allows normal blood flow.

The study you referenced, led by Stanford University and New York University, assessed the medical outcomes of more than 5,100 patients living with moderate to severe coronary artery disease. Researchers divided the study participants into two groups. One group underwent bypass surgery or received a stent. Participants in the other group were prescribed heart medication and instructed to make lifestyle changes, including regular exercise, a healthy diet and quitting smoking. Researchers then followed both groups for between 18 months and seven years, and tracked any cardiac events.

At the end of the study, researchers found that the surgical procedures proved more successful than medication alone at alleviating exercise-related chest pain. However, in the long run, they saw no difference between the two groups when it came to major coronary events, such as hospitalizations, heart attacks and death. In these instances, medication and lifestyle were as effective as surgical interventions. Whether these new findings help settle what has long been a fierce and sometimes contentious debate about treating coronary artery disease remains to be seen.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Our 76-year-old mom is nervous about getting the special Fluzone shot for older people because a neighbor told her it will make her sick. Is that true? What makes flu shots so important?

Dear Reader: Influenza, commonly referred to as the flu, is a seasonal respiratory illness with symptoms similar to those of the common cold. Both illnesses are caused by viruses, but infection with the influenza virus usually results in symptoms that are more severe and longer-lasting than those of a cold. Unlike a cold, which typically comes on gradually, the onset of the flu is often swift. People who get the flu can experience fever, chills, sore throat, cough, lung congestion, body aches and pains, a stuffy and runny nose, and fatigue or exhaustion. Nausea and diarrhea are possible.

Flu season in the United States is concentrated in the fall and winter. Peak activity occurs between December and February. Symptoms show up from one to four days following infection. Depending on the flu strain, as well as the general health of the individual, it can take up to two weeks for the disease to run its course. Most people recover completely. However, at-risk populations with weaker immune systems, such as the elderly, are at increased risk of complications. These can be moderate, such as sinus and ear infections. Severe complications include pneumonia and, more rarely, myocarditis, an inflammation of the heart muscle, or encephalitis, a brain inflammation. In cases where the presence of the influenza virus triggers an extreme inflammatory response, it’s possible for the patient to develop sepsis, a life-threatening infection.

The special flu shot you refer to is called Fluzone High-Dose, a vaccine that contains four times as much antigen as the standard dose. Antigen is the part of the vaccine that causes the body to build up immunity. As we age, our immune response to influenza vaccines declines. The intent of the quadruple dose of influenza antigen is to make up for that reduction in clinical effectiveness. Recent studies have found the high-dose vaccine to be 25% more effective at preventing infection in the elderly. It is also associated with a lower rate of hospitalizations among those who do get the flu. However, it’s also true that side effects to the high-dose vaccine are slightly more frequent than to the standard-dose version.

People getting either type of vaccine may experience side effects including pain, swelling and redness at the injection site, as well as headache, fever, muscle aches and tiredness. Each of these are reported to be mild and temporary, lasting less than a day or two.

Whether your mother overcomes her fear of the high-dose vaccine or opts for the standard-dose variety, we think that the most important thing is for her to get a flu vaccine, no matter which kind, as soon as possible. You should get one, too. In fact, all of our readers should get the flu shot.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)