Every time I get ill (cold, flu etc) I take a couple of these wonderful tablets for up to 4 times a day and I, eventually, get better. What exactly is paracetamol? Why is it so effective and is it really not harmful as my doctor would have me believe?
Paracetamol is a pain killer, it does not treat the cause of your illness, it only alleviates the symptoms. From its wikipedia page:
Paracetamol [...], chemically named N-acetyl-p-aminophenol, is a widely used over-the-counter analgesic (pain reliever) and antipyretic (fever reducer).
So, paracetamol does not make you better. Your immune system makes you better. Paracetamol just makes you feel better while you are waiting for your immune system to get an infection under control.
You should be aware that it is only safe in small doses and a toxic dose is not that much more than the recommended one (source):
Risk of severe liver damage (ie a peak ALT more than 1000 IU/L)
Based on the dose of paracetamol ingested (mg/kg body weight):
Less than 150 mg/kg - unlikely More than 250 mg/kg - likely More than 12 g total - potentially fatal
Again from wikipedia:
While generally safe for use at recommended doses (1,000 mg per single dose and up to 4,000 mg per day for adults), acute overdoses of paracetamol can cause potentially fatal liver damage and, in rare individuals, a normal dose can do the same; the risk may be heightened by chronic alcohol abuse, though it is lessened by contemporary alcohol consumption. Paracetamol toxicity is the foremost cause of acute liver failure in the Western world, and accounts for most drug overdoses in the United States, the United Kingdom, Australia and New Zealand.
I am sure someone else can explain the pharmacokinetics and details of action of paracetamol. I just wanted to point out that paracetamol can be dangerous and should be treated with respect.
Paracetamol, also known as acetominophen and Tylenol is a Non Steroidal Anti Inflammatory Drug (NSAID). Other NSAIDs include aspirin and ibuprofen (Advil).
NSAIDs all help with inflammation, reduce fever, but each has its own effect. Aspirin tends to thin the blood more than Paracetomol. Paracetomol also has less effect on inflammation, but acts to reduce fever (antipyretic) and reduce pain (analgesic). Your doctor has probably chosen this prescription because your needs fit better to this drug's properties.
Ibuprofen for instance probably causes more problems more frequently when it's used frequently, one of the most common being ulcers because ibuprofen inhibits generation of stomach acid, but cancer and a slew of other problems can crop up.
While it is true that Paracetamol is the leading cause of pharmaceutical liver damage in North America, its toxicity as a drug is fairly moderate and the high number of cases is due to the fact that it is sold as an over the counter drug (with no prescription required) and is taken millions of times a day. The FDA has recently lowered the dose of Paracetamol to four 300 mg doses a day - but that's still 1.2 g a day.
Its important to watch to see if you are one of those people who have an adverse reaction or if your liver is under stress. You should not use this drug beyond its expiration date - it really does matter in this case.
Still, all told, you probably could just take a handful of aspirin and feel just as good, but this prescription should get you feeling a little better a little faster, especially if you have pain or fever.
It's true what @terdon says that acetominophen is not curing you, but drugs really mostly balance the body - healing never comes from pharmaceuticals, they often just let the body heal with fewer obstacles or discomfort. I know I feel that when my fever comes down that I'm on the mend - though thats not necessarily the case.