Panadol and Aspirin are brand names for the drugs paracetamol and acetylsalicylic acid. They are both popular analgesics (painkillers) and antipyretic (fever-reducing) drugs, used by millions of people around the world.
They have similar structures but have significant differences. Aspirin is also an anti-inflammatory drug and has an anticoagulant (blood-thinning) effect, so can prevent heart attacks. Panadol does neither but is gentler on the stomach than Aspirin.
Aspirin’s action has long been known but that of Panadol is less understood.
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How pain works:
Pain is your body’s way of telling you tissue is being damaged. When that happens, chemicals are released at that site and stimulate nerve endings, which send the pain message to your brain. There are two paths we can take to relieve it. One way is to act on the central nervous system – the brain and spinal cord, which is what Panadol does. The other is to act on the nerves that send the pain message to the central nervous system, which is what Aspirin does.
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Imagine hitting your finger with a hammer. Your finger has nerve endings in it, which register the pain. Damaged tissue also releases chemicals called prostaglandins. Working cells in damaged tissue make them using an enzyme called cyclooxgenase 2 .
Nerves carry the pain signal through your hand, up your arm and into your brain.
Aspirin enters the bloodstream, which carries it through your entire body. Although it is everywhere, it only works where prostaglandins are being made. It blocks COX-2 enzymes, thus reducing prostaglandin production, which in turn reduces pain and inflammation.
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Panadol works on pain’s pathway in the brain and spinal cord, blocking COX-3 enzymes to decrease prostaglandin production.
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Aspirin: Inhibits enzymes called cyclooxygenase (COX), which normally help to produce prostaglandins and thromboxanes around the body. Prostaglandins are a hormone found in virtually all tissues and organs. They have various actions, including transmitting pain information to the brain. Prostaglandins also are linked to the inflammation response and to regulating the body’s temperature. Thromboxanes are chemicals involved in helping blood clot.
As a result of decreasing the production of prostaglandins and thromboxanes, Aspirin reduces some of their effects around the body – pain, inflammation, fever and blood clotting. Aspirin blocks two variants of the enzyme, COX-1 and COX-2. Inhibiting COX-1 is bad for the stomach lining, where prostaglandins serve a protective role, and can cause gastric problems.
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Panadol: New research has found paracetamol selectively inhibits a variant of the cyclooxygenase enzyme, called COX-3, that is found only in the brain and spinal cord. Other variants of the COX enzyme are not significantly affected by paracetamol. This explains why paracetamol relieves pain and reduces fever without the side effects of Aspirin.
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Sources:
www.howstuffworks.com,
www.ch.ic.ac.uk (Imperial College London website), heart.healthcentersonline.com ,
www.assistpainrelief.com ,
www.pharmweb.net ,
www.pa.msu.edu (Michigan State University)
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How do anaesthetics work?
Anaesthetics depress or numb nerve pathways. If you need surgery, chances are you will have some type of anaesthesia to go along with it. The type you receive will depend on various factors, including the nature, site and duration of surgery, and your health status.
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How a general anaesthetic works:
Brain and spinal cord: It isn’t completely understood how general anaesthetics work at the cellular level. It is believed they affect the spinal cord, causing the patient to become immobile, and affect parts of the brain, causing unconsciousness. When anaesthetics reach the bloodstream, drugs that affect the brain pass through other blood vessels and organs, so they are often affected too. Patients must therefore be carefully monitored.
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Inhaled or injected:
General anaesthesia can be administered as an inhaled gas or as an injected liquid. There are several drugs and gases that can be combined or used alone to produce general anaesthesia. Most adults are first anaesthetised with liquid intravenous anaesthetics followed by anaesthetic gases after they are asleep. Children may not like having an injection or drip placed in them while awake so often breathe themselves to sleep with anaesthetic gases given through a mask.
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Reversible: An important property of anaesthetics is reversibility. When surgery is over, the anaesthesiologist shuts off the anaesthetic so the patient can wake from the induced sleep. Once anaesthetic gas is turned off, the bloodstream brings the gas back to the lungs, where it is eliminated. The more soluble the gas is in blood, the longer it takes to eliminate.
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The four types of anaesthetic
General anaesthesia:
General anaesthesia affects brain cells, causing a loss of consciousness. In this state, a person is unaware of what is happening, is pain-free and immobile, and will not remember anything from the time they are anaesthetised. You can be injected with a liquid anaesthetic drug or breathe an anaesthetic gas to make you sleep, or a mixture of both.
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Regional anaesthesia:
Local anaesthetic is injected near the major nerve pathways to the part of the body where the surgeon operates. This nerve block numbs that part of the body and is often used for hand, arm, hip or knee surgery, and for caesarean sections to deliver a baby. You can be wide awake or have other drugs to make you relaxed and drowsy. Examples include spinal and epidural anaesthesia, arm blocks and eye blocks.
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Local anaesthesia:
A local anaesthetic is injected at the site of the surgery to cause numbness. You will be awake. A local anaesthetic is often used when removing small skin lesions.
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Monitored sedation:
Your anaesthetist uses a special range of drugs to keep you comfortable and sleepy but able to respond to questions if needed.
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Having an operation:
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Nil by mouth: Normally, you have to stop eating and drinking about eight hours before an operation because an empty stomach makes you less likely to vomit while under an anaesthetic. When awake, part of the swallowing mechanism involves a reflex that covers the opening into your lungs, which stops you choking.
You lose that reflex when anaesthetised and can inhale vomit into your lungs, which is dangerous.
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Pre-med: Once changed into theatre clothes, you may be given a “pre-med” before going to theatre. This is a tablet or tablets to relax you if you are nervous or to help with your pain relief after the operation.
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Anaesthetic: In theatre, you will be attached to a specialised machine that monitors your heart, blood pressure, oxygen level and breathing throughout the operation.
An intravenous infusion, or drip, is placed in your hand or arm to give you the anaesthetic drugs.
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Sources:
www.howstuffworks.com,
www.anaesthesia.org.nz,
www.cas.ca (Canadian Anaesthesiologists’ Society) en.wikipedia.org
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