What information indicates the client should not take acetaminophen for relief from chronic headaches?

The problem of using this drug for chronic headaches, implies the excessive use of this drug, that may cause intoxication to the liver.

Explanation:

  Acetaminophen is indicated in adults for fever reduction and temporary relief of mild to moderate pain. It reduces fever by acting at the temperature-regulating center in the central nervous system (CNS) and decreases pain sensitivity. Its effect begins 15 to 30 minutes after oral administration and remains for a period of 4 to 6 hours.

  Acetaminophen is metabolized in the liver. The drug follows a pathway in which it generates 90% of a non-toxic substance that poses no risk to the body. The compound left over from this process is toxic, but when the dose of acetaminophen ingested is low, the body can expel it normally.  However, when there is abuse of the drug, the patient consumes alcohol frequently or takes certain types of medications, there is an overload on this "safe" way and its functioning is compromised. In this case, an alternative pathway is activated within the liver itself, generating a toxic substance.

 The problem of using this drug for chronic headaches, implies the excessive use of this drug, that may cause intoxication to the liver.