paracetamol

Known as acetaminophen outside of Europe, paracetamol has been used as an analgesic for over 30 years, and is an effective method of pain relief and fever reduction. It is one of the three main groups of pain-relieving drugs in use by western medicine, the other two being ibuprofen and aspirin.

Paracetamol overdose is often fatal and is a particularly unpleasant way to die, if suicide is your thing there are far more pleasant methods to use.

My IUPAC nomenclature isn't entirely crash-hot, so I'll give what I think is an unambiguous name that allows me to show the derivation of the common name of paracetamol: Para-acetylaminophenol. It's called acetaminophen (N-acetyl-para-aminophenol)in America. To quote my pharmacology lecturer, "'Paracetamol' must have been too easy for them." (for a similar language difference, see adrenaline and epinephrine, for an opposite language difference, see colour and color).

Graphically:

    /¯¯¯\
HO-<  O  >-NHC=O
    \___/    |
             CH3

That's a benzene ring, if the illustration is a little unclear.

Paracetamol is almost an NSAID, except that unlike most non-steroidal anti-inflammatory drugs it does not have an anti-inflammatory effect. The analgesic and antipyretic (anti-fever) effects of NSAIDs are exhibited by Paracetamol.

Paracetamol use is occasionally associated with a rash, but the more significant side effect is liver damage. Chronic use leads to damage, and a high dose in a short time leads to acute liver failure, which is not a fun way to die. This toxicity is due to a saturation of the enzymes which normally metabolise the drug. When these enzymes are all occupied, an alternative pathway is used. If glutathione is not available for this process then cell death occurs. As a result, the effects are sharp with increased dose - if you take less than enough to saturate the enzymes, no worries, but if you take more, bad things happen. The amount required for toxicity varies from person to person. As I am not a doctor, I will not offer advice on dosage.

Paracetamol (PhEur, BP) is the only major analgesic used for relief of moderate pain that is not a Non-Steroidal Anti-Inflammatory (NSAID). It is also an effective anti-pyretic.

Paracetamol in the UK may be sold over-the-counter by any retailer, but may only be supplied in packs of no more than 16 500mg tablets, and no more than two packs may be sold in any single transaction. The justification for this is not that depressed people cannot visit more than one shop, but rather that it reduces the number of opportunistic suicides by people who find fatal dosages lying around in their cupboards. (It is well-known in the UK that paracetamol is fatal in relatively small doses).

Paracetamol in the official name of this drug in European and British Pharmacy, while in the US it is officially known as "Acetaminophen". Panadol and Tylenol are brand names under which this drug is sometimes sold. Paracetamol is very cheap, although branded versions may have advanced formulations that speed or otherwise modify the release and absorption of the drug.

Ibuprofen and aspirin are not groups of drugs, but specific drugs belonging to the NSAID group. It is often considered safe to mix ibuprofen and paracetamol each up to their recommended maximum dosage, but REMEMBER THAT I AM NOT A DOCTOR NOR ANY OTHER KIND OF HEALTH PROFESSIONAL. For your information, I reproduce the list of questions that one should answer "no" to before taking paracetamol without medical supervision, as given on the packet I have before me (I assume that all uncapitalised drug names are the standard British Pharmacy names):

• Are you allergic to paracetamol, or any other ingredient?
• Do you take medicines for nausea or sickness, such as metoclopramide or domperidone?
• Do you take Cholestyramine for high cholesterol or high blood fats (lipids such as triglycerides)?
• Do you take Warfarin or other medicines to thin the blood or reduce risk of clotting?
• Do you take any other medicine including any not prescribed by your doctor?
• Are you pregnant or trying to become pregnant?
• Do you have liver or kidney disease?