para-aminophenol derivative analgesics include acetanilide, acetphenetidine and acetaminophen. here I describe on acetaminophen or paracetamol. paracetamol is an NSAID drug.it is an OTC drug. Paracetamol also known as acetaminophen is a widely used over the counter drug for pyrexia and mild to moderate pain in all age groups. It has similar efficacy to aspirin, but has no demonstrable anti-inflammatory activity; it is less irritant to the stomach and for that reason is now generally preferred to aspirin, particularly in the elderly. Paracetamol has been in use for the past 60-70 years and ever since aspirin was found to be a causative agent for Reye syndrome in 1980s; paracetamol has come to stay as the drug of first choice for fever in children. It is the most common over the counter drug used for self-medication by mothers in the age group 12 years and below.Over dosage with paracetamol is particularly dangerous as it may cause hepatic damage which is sometimes not apparent for 4 to 6 days. Many reported cases of severe hepatotoxicity in children have been attributed to cumulative toxicity from repeated doses rather than acute intoxication from a single massive overdose.Use of adult rather than pediatric preparations,failure to read and understand instructions on the label, or use of an incorrect measuring device or preparation were cited as the usual causes of unintentional overdosing in a group of patients who underwent liver transplant due to paracetamol toxicity.Assessing the knowledge and practices on paracetamol administration among caregivers of the pediatric age group will enable doctors to identify shortcomings and intervene in view of preventing over dose.
Chemical name of paracetamol:
The chemical name of paracetamol is N-(4-hydroxyphenyl)acetamide .
Mode of action:
Paracetamol is used worldwide for its analgesic and antipyretic actions. It has a spectrum of action similar to that of NSAIDs and resembles particularly the COX-2 selective inhibitors. Paracetamol is, on average, a weaker analgesic than NSAIDs or COX-2 selective inhibitors but is often preferred because of its better tolerance. Despite the similarities to NSAIDs, the mode of action of paracetamol has been uncertain, but it is now generally accepted that it inhibits COX-1 and COX-2 through metabolism by the peroxidase function of these isoenzymes. This results in inhibition of phenoxyl radical formation from a critical tyrosine residue essential for the cyclooxygenase activity of COX-1 and COX-2 and prostaglandin (PG) synthesis. Paracetamol shows selectivity for inhibition of the synthesis of PGs and related factors when low levels of arachidonic acid and peroxides are available but conversely, it has little activity at substantial levels of arachidonic acid and peroxides. The result is that paracetamol does not suppress the severe inflammation of rheumatoid arthritis and acute gout but does inhibit the lesser inflammation resulting from extraction of teeth and is also active in a variety of inflammatory tests in experimental animals. Paracetamol often appears to have COX-2 selectivity. The apparent COX-2 selectivity of action of paracetamol is shown by its poor anti-platelet activity and good gastrointestinal tolerance. Unlike both non-selective NSAIDs and selective COX-2 inhibitors, paracetamol inhibits other peroxidase enzymes including myeloperoxidase. Inhibition of myeloperoxidase involves paracetamol oxidation and concomitant decreased formation of halogenating oxidants (e.g. hypochlorous acid, hypobromous acid) that may be associated with multiple inflammatory pathologies including atherosclerosis and rheumatic diseases. Paracetamol may, therefore, slow the development of these diseases. Paracetamol, NSAIDs and selective COX-2 inhibitors all have central and peripheral effects. As is the case with the NSAIDs, including the selective COX-2 inhibitors, the analgesic effects of paracetamol are reduced by inhibitors of many endogenous neurotransmitter systems including serotonergic, opioid and cannabinoid systems. There is considerable debate about the hepatotoxicity of therapeutic doses of paracetamol.
use of paracetamol:
Paracetamol is a commonly used medicine that can help treat pain and reduce a high temperature (fever).It's typically used to relieve mild or moderate pain, such as headaches, toothache or sprains, and reduce fevers caused by illnesses such as colds and flu.Paracetamol is often recommended as one of the first treatments for pain, as it's safe for most people to take and side effects are rare.
Side effects of paracetamol
Side effects from paracetamol are rare, but can include:
an allergic reaction, which can cause a rash and swelling.flushing, low blood pressure and a fast heartbeat – this can sometimes happen when paracetamol is given in hospital into a vein in your arm.blood disorders, such as thrombocytopenia (low number of platelet cells) and leukopenia (low number of white blood cells).liver and kidney damage if you take too much (overdose) – this can be fatal in severe cases.Speak to a pharmacist or doctor if you develop any troublesome side effects that you think could be caused by paracetamol.
Overdoses of paracetamol
Taking too much paracetamol, known as an overdose, can be very dangerous.If taken more than the recommended maximum dose, go to your nearest accident and emergency (A&E) department as soon as possible.It can be helpful to take any remaining medicine and the box or leaflet with you to A&E if you can.Some people feel sick, vomit or have abdominal (tummy) pain after taking too much paracetamol, but often there are no obvious symptoms at first.
