To Your Good Health: Case of anaphylactic shock might be due to methocarbamol

My question is about methocarbamol, known as Robaxin. My relative has been taking this for about two years for back pain. He then developed a sudden severe allergic reaction and went into anaphylaxis. He fought it all night, not knowing what was happening, and by morning, he had to go to the hospital. Could this be due to methocarbamol? If so, can this happen again? He has no known allergies, and this had never happened before. The only other thing was maybe burning a lemon-scented candle in his bedroom, but he’s burned candles before in his bedroom. He is 27 years old and in good health.

Anaphylaxis is a severe allergic reaction to a foreign protein or carbohydrate, called an “allergen.” It is caused by a release of inflammatory chemicals from immune cells. It can be antibody-mediated, which is more common, or occur without antibodies, which is less common.

These chemicals can cause swelling of the airway and death through asphyxiation. They can also affect the heart and blood vessels, causing shock and circulatory collapse, which can also lead to death. The onset of symptoms is typically minutes to hours after exposure to the allergen.

In 95% of cases, the symptoms disappear, but there are cases of “biphasic anaphylaxis” where symptoms reappear usually within 12 hours. There are unusual cases of very delayed anaphylaxis, such as with alpha-gal syndrome — a meat allergy that is acquired after tick exposure.

Medications are one of the most common causes of anaphylaxis, and I did find case reports of anaphylaxis with methocarbamol in a person who had been taking it previously. I found another case report of a person with prolonged anaphylaxis after methocarbamol.

It is uncommon, but not impossible to develop anaphylaxis to a medicine that you have been taking for years.

If your relative isn’t taking any other medications and had no unusual foods on that day, I strongly suspect that methocarbamol was the cause and recommend never taking it again as it can absolutely happen again.

A candle smoke allergy is documented, and a variety of symptoms can be caused by candle smoke in sensitive individuals. I found a source saying that anaphylaxis from inhaling candle smoke is “rare,” but could not find a well-documented case.

Finally, methocarbamol is a muscle relaxant and isn’t always a good choice for long-term treatment. My experience is that in many people, the beneficial effects wear off as the body gets used to the medicine, which can happen within a week.

Are there health benefits to taking fish-oil capsules? If so, what’s the proper dosage? I’m a fit, healthy 70-year-old male.

The benefit of fish oil is one topic in medicine where we seem to keep changing our mind due to studies that yielded some conflicting results.

What is clear is that fish oil reduces triglyceride levels. In people with high triglyceride levels, especially people who are at a relatively high risk due to other reasons — such as diabetes and low HDL cholesterol — then fish oil is a reasonable treatment.

Most experts prefer the pharmaceutical-grade icosapent ethyl, known as Vascepa, or EPA/DHA, known as Lovaza, which are highly purified and aren’t oxidized.

For people who are at a lower risk, the benefit is probably modest; however, fish oil is generally safe. There may be a small increase in the risk of atrial fibrillation with high doses.