Pharmacology of Paracetamol: Mechanism of Action, Adverse Effects and Interactions with Chinese Herbs and Nutritional Supplements

Running head: PHARMACOLOGY
Pharmacology
Name of the student:
Name of the University:
Author’s note

1PHARMACOLOGY
Paracetamol or Acetaminophen is a drug that belongs to the drug class of analgesics and
antipyretics. It is indicated for use in patients with fever and mild to moderate pain such as
migraine. Although it is a weaker analgesic compared to NSAIDs (non-steroidal anti-
inflammatory drugs) or COX-2 selective inhibitors, it is used because of better tolerance
(Graham et al., 2013). The essay gives better understanding of the therapeutic action and
pharmacology of the drug by discussing by discussing about the mechanism of action, route of
administration, adverse effects and contraindications of the drug. It also gives idea regarding the
human physiology of the disease to which the drug is indicated. The essay discusses about
interactions between paracetamol and Chinese herbs and suggests strategies to prevent adverse
reactions between the two.
Parecetamol is renowned as one of the widely used non-prescribed medication of its
therapeutic effect on pain and fever related outcomes. The main factor involved in the
therapeutic action of the drug is the function of paracetamol in inhibiting prostanglandin
synthesis within the central nervous system. However, unlike other drugs, it has no anti-
inflammatory benefits (Mallet, Eschalier & Daulhac, 2017). Although the exact mechanism of
the drug of action is not fully established in research literature, most research study show the
function of the drug in inhibiting the COX pathways and exerting central actions to provide relief
from pain symptoms. Sharma and Mehta (2013) gives the evidence regarding the detailed action
of the drug in inhibiting production of prostaglandins. Cyclooxygenase or prostaglandin H2
synthetase is an enzyme responsible for the metabolism of arachidonic acid to prostanoids and it
contain two active sites namely COX and the peroxidase. The enzymatic activity of COX occurs
in the oxidized form. However, paracetamol forms co-substrate at the POX site to interfere with
the function of the COX enzyme. Parecetamol act as a potent inhibitor of prostaglandin synthesis

2PHARMACOLOGY
when level of archidonic acid is low. However, the same action is not seen when the
concentration of hyperperoxide is high. Hence, differential activity of the parecetamol in brain is
seen (Figure 1).
Figure 1: Mechanism of action of paracetamol. Source: (Sharma & Mehta, 2013).
Paracetamol has been found to have low anti-inflammatory and anti-platelet activity and
another reason cited for low activity in this area is that unlike NSAIDs which act on COX-1 and
COX-2 site, paracetamol acts on a spliced variant of COX-1. As this variant is inactive at the site
of injured or inflamed tissue, the drug cannot render any anti-inflammatory effect (Sharma &
Mehta, 2013). However, because of antipyretic and analgesic property of the drug, its therapeutic
use is found for patients from headaches, pain, backaches, toothaches, osteoarthritis and fever. It
is the first line of drug for treatment of pain. However, it is often combined with drugs like