Does Tylenol Exert its Analgesic Effects via the Spinal Cord?

What do we (not) know about how paracetamol (acetaminophen) works? (Toussaint et al., 2010). . .From the beginning, the focus of the search for paracetamol’s analgesic mechanism has concentrated on the central nervous system. When administered intraventricularly [i.e., directly into the ventricular system of the brain], acetaminophen produces no significant analgesia (115, 132). This finding lead to attempts to inject acetaminophen into the spinal cord (i.t.), which produced marked dose-related antinociception (132).Yesterday’s post about Tylenol as a cure for mortality salience and existential dread got me a little worked up. The first author’s public endorsement of acetaminophen as a possible treatment for chronic anxiety disorders was too much to handle (along with the less than stellar experimental rigor). Is watching a 4 min clip of a David Lynch film really the same thing as a clinically diagnosed psychiatric disorder (Randles et al., 2013)? Why Tylenol and not other pain relievers? What is the hypothesized mechanism of action? Wouldn’t we already know by now, from epidemiological studies at the very least, if Tylenol was an effective anti-anxiety medication?So I started wondering about acetaminophen's actual mechanism of action. I was quite surprised that it's somewhat mysterious. Randles et al. cited one paper on this:Second, acetaminophen affects a number of brain regions, some of which are not directly related to physical or social distress (Toussain...
Source: The Neurocritic - Category: Neurologists Source Type: blogs