抄録
Acetaminophen is an antipyretic and analgesic drug that has a long history of 100 years or more and has been adopted in the WHO Model List of Essential Drugs in the category of non-opioids and non-steroidal anti-inflammatory medicines. In Japan, the analgesic effects of acetaminophen have not been sufficiently recognized, and NSAIDs have been used in the treatment of pain, even though acetaminophen is the first-choice analgesic worldwide.
Since acetaminophen, which is different from NSAIDs, does not inhibit the activity of COX-1 and COX-2, the risk of developing the 3 well-known adverse reactions of NSAIDs, peptic ulcer and gastrointestinal hemorrhage, renal dysfunction, and hemorrhage and platelet dysfunction, is very low. Aspirin is known to induce asthma and Reye's syndrome, however, acetaminophen is scarcely associated with these adverse reactions and can be used for treatment of viral diseases such as chicken pox and influenza. The safety of acetaminophen in pregnant women and elderly patients has been confirmed, and the position of acetaminophen as the first-choice analgesic drug has been established worldwide. In Japan, on the other hand, the effect of acetaminophen has not been sufficiently recognized due to the small doses (single dose, 300-500 mg; daily dose, 900-1500 mg/day) compared to other nations (single dose, 1,000 mg; daily dose, 4000-6000 mg/day). Further, the precautions for use indicated in the package insert of acetaminophen are the same as that indicated for NSAIDs; this may be a possible reason why acetaminophen has been misunderstood to be a kind of anti-inflammatory medication (NSAIDs) in Japan.
From above-mentioned viewpoint, the dosage of acetaminophen and expression of the precautions in packaging insertion should be reconsidered. The dosage of acetaminophen as a nonprescription drug should also be reconsidered because the dosage in OTC is further lower than that of the prescription drug. It is expected that when a more reliable analgesic effect is obtained by the administration of a higher dosage of acetaminophen and a more accurate profile of its safety is recognized, this drug will become the first-choice analgesic in Japan.
