Dear Doctor: Last year, my best friend, who was home in bed with a bad case of the flu, died of a heart attack. He was fit, strong and relatively young -- only 42 years old -- and his death was a shock. But now research suggests having the flu actually increases the risk of a heart attack. Can we protect ourselves?

Dear Reader: We're very sorry for your loss and understand why it would be shocking. When we think of the complications that arise from the flu, it's usually something like an ear or sinus infection. When things get more serious, flu can lead to pneumonia.

However, inflammation caused by the influenza virus can affect the body in even more severe and unexpected ways. This includes developing encephalitis or myocarditis, which are inflammation of the brain and the heart respectively, or sepsis, a full-body inflammatory response that can lead to multiple-organ failure and death. Individuals with the flu can also sometimes experience a worsening of chronic medical conditions, such as asthma or heart disease.

Now, as you mention, researchers have uncovered what they believe is a surprisingly strong connection between influenza infection and heart attack. In a study published last year in the New England Journal of Medicine, scientists at the Institute for Clinical Evaluative Sciences in Toronto reported that in the seven days following a lab-confirmed diagnosis of influenza, heart attacks were six more times as likely as they were either a year prior to or following the diagnosis. The researchers arrived at this conclusion using details from hospital admissions in Ontario between 2008 and 2015. They analyzed data from individuals with confirmed cases of influenza, as well as 364 heart attacks.

According to the data, the hospital saw 3.3 heart attack admissions per week in the year before and after a flu diagnosis. But during the week of a flu diagnosis, the heart attack rate rose to 20 admissions per week. Of the 332 people in the study who had a heart attack during the seven-day window following a flu diagnosis, 69 percent had not received a flu shot that year. The data also suggested that individuals older than 65 were at a slightly higher risk than younger people of suffering a post-flu heart attack. Other acute respiratory infections can also increase heart attack risk, although not as sharply as influenza, according to the study.

Previous studies have tied influenza infection to a three-fold increase in the risk of stroke. This range of extreme complications is believed to arise in response to the sudden and systemic inflammation that accompanies an acute respiratory infection.

The best way to protect yourself against the flu is by getting your annual flu shot. Research has shown that hospitalizations and deaths are markedly lower among people who get a flu vaccine when compared with those who do not. People who get the flu despite being vaccinated tend to have milder and shorter illnesses. Anyone who experiences heart attack symptoms during or shortly after an acute respiratory illness, including chest pain, arrhythmia, shortness of breath, exhaustion or edema, should seek immediate medical care.

(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 youngest daughter caught a cold over the holidays and was pretty miserable. She had just turned 2, so we didn't want to give her cough or cold medicines, but we did want to help her feel better. What could we have done? Would honey have helped?

Dear Reader: The good news is that for most children and in most cases, the common cold won't cause serious complications. The bad news, as anyone with small children knows, is that colds will absolutely convey a certain level of discomfort and misery. Waking hours can become marathons of crankiness because the young patient is beset by aches and pains, copious mucus and feeling generally crummy. At night, the little one's bouts of coughing mean a sleepless night for parent and child alike.

However, tempting as it may be, don't reach for an over-the-counter (OTC) cough medicine. According to the U.S. Food and Drug Administration, OTC cough medicines are not recommended for children younger than 2 years old. Many doctors recommend waiting even longer than that to administer OTC medications, so check with your pediatrician to see what they recommend. And as long as we're on the subject, prescription cough medicines that contain codeine or hydrocodone should never be used in children younger than 18 years old. Always read the labels of OTC cough medicines before dispensing them to children because some may contain codeine.

We've successfully mapped the human genome but as of yet, there is no cure for the common cold. Antibiotics, which target bacteria, aren't effective against colds, which are caused by viruses. And with OTC medications not suitable for young children, we're left with the comfort measures our grandmothers would have approved of.

The main symptoms of the common cold are the result of the immune system fighting off the virus. Whether it's fever, sneezing, coughing or that nonstop output of mucus, each plays a physiological role in getting your child healthy again. The goal isn't to eliminate the symptoms completely, but instead to make them easier to live with. That means keeping your little one hydrated with plenty of fluids, both warm and cold. Using a cold air humidifier can help ease nasal congestion. When nasal mucus becomes thick and gluey, you can use saline drops, available at the pharmacy, to help loosen things up. Tender, inflamed nostrils are a particularly unpleasant side effect of a runny nose. We find that a dab of A&D Ointment rubbed around the perimeter of the nostrils offers instant relief and prevents further chapping.

Honey, as you mentioned, can help soothe a raw and inflamed throat in children older than a year. In fact, several studies have shown that honey actually relieves cough symptoms and can help kids to get a better night's sleep. Please note that honey is not recommended for children younger than a year old because it may occasionally contain bacteria that can cause botulism. Also important is a balanced diet and plenty of rest, so that the body's immune system can do its best work.

(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: What can you tell me about tianeptine, which a friend is buying online? All I know is that it's an antidepressant that people are taking instead of opioids.

Dear Reader: Tianeptine, marketed as Coaxil or Stablon, is a prescription medication used to treat major depression in more than 60 countries in Europe, Asia and Latin America. It is also used to treat anxiety, asthma, Parkinson's disease and irritable bowel syndrome. The drug has not been approved for medical use by the U.S. Food and Drug Administration, which is why your friend is buying it online, where it is marketed as a dietary supplement or sold as a research chemical.

Human and animal studies show that tianeptine, which was patented in France in the 1960s and first marketed in 1989, is an opioid receptor agonist, as are codeine, fentanyl, hydrocodone and heroin. The drug stimulates opioid receptors in the brain, which leads to a cascade of chemical changes that, for some people, offer relief from symptoms of depression and anxiety.

However, as tianeptine came into wider use, it became evident that users were at risk of addiction, abuse and withdrawal, much as with opioids. Although even five years ago most people had never heard of the drug, statistics collected by poison control centers show that is rapidly changing. Between 2000 and 2013, there were a total of 11 calls regarding tianeptine exposure. In just the next three years, that number ballooned to 207 calls. Some addiction experts say it's no accident that tianeptine use is spiking just as new regulations are making it more difficult to obtain prescription opioids. According to the Centers for Disease Control and Prevention, the drug has "an abuse potential in former opiate drug users."

The exponential increase in tianeptine use, which epidemiologists warn is just the tip of the iceberg, has led the CDC to flag abuse of the drug as an emerging public health risk. In response, individual states are now taking steps to regulate it. At the end of 2018, Michigan became the first state to schedule the drug as illegal.

The negative effects of tianeptine are sometimes associated with abuse, but more often with withdrawal. The former occurs when users ingest significantly higher than the recommended dose, which they may do in pursuit of euphoric effects. The typical therapeutic dose is 25 mg to 30 mg. When taken in doses over 100 mg, tianeptine can mirror the effects of prescription opioids.

Many people report they seek out the drug for its calming, anti-anxiety effects. Taking too much tianeptine can cause nausea and vomiting. A tianeptine overdose can also cause slowed or irregular breathing or respiratory distress, as well as altered heart activity, all of which requires immediate emergency medical attention.

When it comes to abruptly stopping the drug, side effects can include insomnia, excitability, depression, anxiety and an inability to experience pleasure. In extreme cases, agitation, paranoia and physical outbursts have been reported. Withdrawal from the drug can be difficult and is best done with the help of addiction professionals.

(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.)