By Eduardo Gonzales
Q: Last June, I read a Facebook post that says two Filipinos in their early 20s became comatose after drinking alcoholic drinks. This story was essentially confirmed a couple of days later when the Department of Health issued a statement stating that two hospital patients have indeed shown symptoms of methanol poisoning. What is methanol? How does it get into alcoholic drinks?—[email protected]
A: There are many types of alcohol, ethanol (ethyl alcohol) and methanol (methyl alcohol) are two of them. The alcohol in alcoholic beverages such as beer, wine, and spirits is ethanol. The ethanol in alcoholic beverages comes from the natural fermentation of the sugar that is found in fruits, cereal grains, and other starches. When taken in moderation, ethanol is safe. Methanol, on the other hand, is a highly toxic alcohol that is found in various household and industrial agents such as windshield washer fluid, carburetor cleaner, copy machine fluid, perfumes, food warming fuel, and other types of fuel. Methanol can cause blindness and death. As little as 10 ml of pure methanol can cause blindness by destruction of the optic nerve. The median lethal dose of methanol is 100 ml, but 15 ml can be fatal.
Causes of methanol poisoning
Methanol poisoning is often due to alcoholic beverages that have been adulterated with methanol for profit motives, in as much as methanol is much cheaper than ethanol. Sometimes. however, methanol in alcoholic beverage is due to distilling and fermenting errors, which occur more often in home brewed beverages. Commercially made spirits are usually safe since manufacturers of these products use technology that separates methanol from ethanol, thereby making the drinks nontoxic. Homebrew systems, however, are not technically advanced. Sometimes they are unable to remove methanol from the brew. Incidentally, a few cases of methanol poisoning are due to intentional (i.e., suicidal attempts) or accidental ingestion of methanol-containing products.
Methanol poisoning is not as widespread in the Philippines as it is in countries such as India, Indonesia, and Malaysia, but there are occasional cases.
Methanol is colorless. It is not pungent enough to dilute the taste or odor of an alcoholic beverage that is why drinkers who partake of alcoholic drinks that contain methanol do not notice anything wrong with their drinks. When ingested, methanol is converted into formaldehyde in the stomach and then into formic acid in the liver. Formic acid then seeps into the bloodstream and spreads throughout the body. Formic acid is toxic because it deprives body cells of oxygen and it increases the acidity of blood, which disturbs many metabolic processes of the cells.
Signs and symptoms of methanol poisoning
The initial symptoms of methanol poisoning are similar to regular alcoholintoxication—nausea, vomiting, headache, dizziness, lack of coordination, and confusion. As in ethanol intoxication, sufficiently large doses of methanol cause unconsciousness and death.
Once the initial symptoms have passed, a second set of symptoms appears, six to 30 hours later. They include blurring or complete loss of vision, dilated pupils, breathing difficulty, weakness and fatigue, leg cramps, low blood pressure, confusion, agitated behavior, dizziness, difficulty walking, bluish-colored lips and fingernails, diarrhea, nausea, severe abdominal pain, liver problems such as jaundice and bleeding, pancreatitis, vomiting of blood, seizures, and coma. These symptoms result from the accumulation of toxic levels of formic acid in the blood, and may progress to death by respiratory failure.
What to do to methanol poisoning victim
A methanol poisoning victim should be brought to a hospital. While it may seem illogical, giving the patient hard alcoholic drinks will help if it will take time to reach a hospital, because ethanol contained in hard drinks will help slow the breakdown of methanol into formic acid. In the hospital, methanol poisoning patients are given more ethanol, bicarbonate to buffer the acidosis and folic acid to convert the formic acid into carbon dioxide and water, but the best way to remove the methanol from the body is by dialysis.
There is an antidote for methanol poisoning in the form of fomepizole administered intravenously, but the drug is expensive and it is not available in the Philippines.
(Note: email inquiries on health matters to: [email protected])