By Peggy O'Farrell
Enquirer staff writer

With cold season approaching, Dr. Guy Neff has a warning for people who automatically reach for a few popular over-the-counter remedies: Too much of a good thing can cost you your liver.

Neff, the medical director of liver transplantation at University Hospital, says consumers need to pay more attention to how much acetaminophen, or Tylenol, they take every day.

"The amount of acetaminophen that someone can take easily adds up," he says.

How much is too much?

Five grams of acetaminophen a day for a week "will destroy a liver," Neff says. And it's not hard to reach that level.

An example: Most of us have probably downed a couple of tablets of a multi-symptom cold remedy, then chased it with a couple of Tylenol.

Not many of us do the math. One Tylenol Extra Strength caplet has 500 milligrams of acetaminophen. The label advises taking a maximum of eight caplets a day - that's four grams of acetaminophen right there, and some people tend to take three or four caplets at a time.

Add in a sinus headache or cold remedy that contains acetaminophen, and it's easy to get another gram or two in the daily total.

All medications are broken down, or metabolized, in the liver. One of the metabolites of acetaminophen is toxic to the liver. In high amounts, it can destroy the liver, Neff says.

Add echinacea to the arsenal to combat a cold "and right there you've got two agents that may help with the infection but ultimately might be toxic to the liver."

Maximum dose

Healthy people who eat well should take a maximum of two to three grams of acetaminophen daily, Neff says.

People with liver disease shouldn't take acetaminophen at all. An acetaminophen overdose or overuse can cause liver damage severe enough to require a transplant, he says. It can also be fatal.

Acetaminophen isn't the only culprit for liver damage. Statins, commonly prescribed to reduce cholesterol levels, can cause liver damage, as can other prescription drugs.

So can several herbal remedies - including chaparral tea, kava kava and saw palmetto, along with echinacea - if dosage recommendations aren't followed, Neff says.

E-mail pofarrell@enquirer.com