How Does the Liver Process Advil Tylenol & Aleve?

Advil, Tylenol and Aleve are all brand names for the over-the-counter medications ibuprofen, acetaminophen and naproxen sodium, respectively. All three are non-narcotic pain relievers. Ibuprofen and naproxen sodium are also non-steroidal anti-inflammatory drugs, commonly called NSAIDs.

Ibuprofen is processed by the liver in two different ways, oxidation and glucuronic acid conjugation. 25 percent is oxidized by the liver to form (+)-2-[p-(2hydroxymethyl-propyl) phenyl] propionic acid and 37 percent to (+)-2-[p-(2carboxypropyl)phenyl] propionic acid. 14 percent is processed by the liver to form the glucuronic acid conjugate. All three are excreted in the urine.

Acetaminophen is processed by the liver in three different ways, glucuronidation, sulfation and oxidation. 47 to 62 percent of a dose of acetaminophen is processed by the liver to form glucuronide conjugates, which are inactive and non-toxic. 25 to 36 percent of a dose of acetaminophen is processed by the liver to form sulfate ester conjugates, which are also inactive and non-toxic.

Five to 8 percent of a dose of acetaminophen is processed by the liver to form N-acetyl-p-benzoquinoneimine (NAPQI). NAPQI then rapidly reacts with glutathione in the liver cells to form cysteine and mercapturate conjugates, which are inactive and non-toxic. The conjugates from all three processes are excreted in the urine.

Naproxen sodium is processed by the liver in two different ways. Some naproxen sodium is processed to form 6-0-desmethyl naproxen. Both naproxen sodium and 6-0-desmethyl naproxen are processed by the liver to form acylglucuronide conjugates. The conjugates make up 66 to 92 percent of the naproxen that is excreted in the urine.