[Paleopsych] NYT: Perils of Pain Relief Often Hide in Tiny Type

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Personal Health: Perils of Pain Relief Often Hide in Tiny Type
New York Times, 5.5.3
http://www.nytimes.com/2005/05/03/health/03brod.html

    By [1]JANE E. BRODY

    If ever there was a classic case of "no free lunch," popular pain
    control medications are it. There's not one without a potentially
    serious risk. Yet, far too many people use them carelessly, without
    adequate attention to dosage and warnings about possible risks.

    For over a century, aspirin was the pain drug of choice, until data
    emerged on the rather large number of bleeding-related deaths this
    time-honored medicine caused each year. In fact, many pharmaceutical
    experts say that if aspirin had to go through the Food and Drug
    Administration's approval process today, it would never make it to
    market.

    Along came some dandy substitutes, now also sold over the counter
    under brand names and as generics: ibuprofen (Advil, Motrin IB) and
    naproxen (Aleve). Ibuprofen and naproxen, known as nonsteroidal
    anti-inflammatory drugs, or Nsaids, can equal or outdo aspirin's
    action against painful inflammation but at less risk of bleeding.

    But they, too, can have serious side effects: they can irritate the
    gastrointestinal tract and possibly cause ulcers. People who use
    Nsaids chronically are often told to take an anti-acid drug to protect
    their stomachs.

    This problem opened up a market for a new kind of drug called a cox-2
    inhibitor, sold as Celebrex, Vioxx, Bextra and Mobic. These drugs are
    as good or better than ibuprofen for pain, although as patented
    prescription medications they greatly multiplied the cost of pain
    relief.

    The cox-2 inhibitors were considered safer because they reduced the
    risks of bleeding and gastrointestinal damage. And as major
    moneymakers, they were heavily promoted, especially to the millions
    who need relief for chronic problems.

    Alas, these, too, have come under serious fire as their use mushroomed
    and evidence emerged linking them to heart attacks and strokes among
    users already at risk for these problems. With many
    multimillion-dollar lawsuits looming, Vioxx was the first to be
    withdrawn from the market, recently followed by Bextra. Both drugs may
    come back, accompanied by more stringent warnings. Or their cox-2
    cousins, Celebrex and Mobic, may join the ranks as drugs gone by.

    Problems also accompany other prescription painkillers, like the
    opioids, to be discussed in greater detail in a future column.

    This brings us to an entirely different drug, acetaminophen, long used
    to counter fever and occasional aches and pains like tension
    headaches. But now acetaminophen is being hailed as an excellent first
    choice for the relief of chronic pain.

    Can Tylenol Take Over?

    Acetaminophen, often referred to by its most popular brand name,
    Tylenol, has no anti-inflammatory action. Nor does it cause bleeding
    or gastrointestinal distress. Many pain specialists say it should be
    considered first for relief for the persistent pain of osteoarthritis
    and prolonged pain of muscle or joint injuries.

    All in all, acetaminophen is a safe drug for children and adults.
    Despite the many millions of doses taken by Americans each year, few
    reports of serious side effects emerge when acetaminophen is used in
    the dosages recommended by manufacturers.

    For example, in a study published a decade ago evaluating the
    experience of 28,130 children who had taken acetaminophen, there was
    no increased risk of gastrointestinal bleeding, kidney failure,
    life-threatening allergic reactions or Reye's syndrome, a potential
    fatal side effect of aspirin when given to children with viral
    infections.

    Acetaminophen is also considered safe for women who are pregnant or
    breast-feeding, although they are wisely advised to check first with
    their doctors. And acetaminophen is the pain reliever of choice for
    those with serious allergies who may be at risk of severe allergic
    reactions from aspirin and Nsaids.

    Perhaps as a testament to its safety, acetaminophen is found, not only
    on its own in a variety of dosages, but also in combination with other
    medications, over the counter and prescription. If consumers are
    unaware of its presence in different medications, or if they fail to
    adhere to cautionary statements about dosages, it is possible to take
    too much acetaminophen inadvertently.

    As with any other medicine, with acetaminophen it is critically
    important to keep in mind this irrefutable adage: The dose makes the
    poison.

    For example, no one questions the safety of following recommended
    doses. If you can read the fine print on the label, it will tell you
    that for adults and for children 12 and older, two 500-milligram
    tablets or capsules can be taken every 4 to 6 hours, as long as no
    more than 8 tablets (a total of 4,000 milligrams) are taken in a
    24-hour period - unless a physician says otherwise.

    Taking more than 4,000 milligrams a day of acetaminophen on a chronic
    basis can damage the liver of an adult. The danger dose would be far
    smaller for young children.

    It is easier than you may think to take more than 4,000 milligrams a
    day. With the higher-dose tablets (650 milligrams each) now sold to
    treat arthritis, you can easily exceed the safety limit if you do not
    follow the instructions to take 2 tablets every 8 hours, for a maximum
    daily dose of 6 tablets in 24 hours, adding up to 3,900 milligrams a
    day.

    Even if you follow these directions, you can exceed the recommended
    daily dose if you also take another medication - say, an
    over-the-counter cold or flu remedy - that contains acetaminophen.

    The label on my Tylenol Arthritis Pain has a clearly stated warning:
    "Do not use with any other product containing acetaminophen." But
    until writing this column, I admit I never read that warning, and I'd
    guess that more than 90 percent of other users haven't read it either.
    Without a magnifying glass, many elderly people who are the most
    likely users of an arthritis drug would have trouble reading the
    labels on this and many other medicines like it.

    A second warning on acetaminophen says: "If you drink three or more
    alcoholic drinks every day, ask your doctor whether you should take
    acetaminophen or other pain relievers/fever reducers. Acetaminophen
    may cause liver damage."

    A Liver Under Siege

    So, if your liver is already under attack from alcohol, acetaminophen
    can be that last straw, resulting in liver failure.

    This year, the journal Emergency Medicine warned physicians about the
    hazards of overdoses of acetaminophen. Dr. Shirley Kung and Dr. Kennon
    Heard wrote that acetaminophen poisoning could often be much worse
    than it seemed at first.

    Nausea and vomiting can progress to complete liver failure in as
    little as 24 hours unless the problem is promptly recognized and the
    proper antidote given within 24 hours of a toxic dose. To fully
    prevent liver injury, the antidote should be given within eight hours.

    Each year, more than 100,000 calls related to acetaminophen are made
    to poison control centers in the United States, and about 150
    acetaminophen-related deaths are reported. Some cases result from
    deliberate overdoses by people trying to commit suicide. But many
    others are accidental, like the one described in the journal: an
    18-month-old child with a fever and cough for three days who had been
    given acetaminophen every two to four hours.

    Other cases result when people whose livers are damaged by other
    disease take acetaminophen for respiratory infections or pain.