D.3.1

=**__D.3.1 Describe and explain the different ways that analgesics prevent pain.__**=

Analgesics, or painkillers, relieve pain in your body by acting on the peripheral and central nervous systems.
 * Definition:**
 * Mild Analgesics**

Mild analgesics function by intercepting the pain stimulus at the source, often by interfering with the production of substances (for example, protasgladins) that cause pain, swelling or fever.

Examples:
 * Aspirin
 * Acetaminophen (Paracetamol, Tylenol)
 * Ibuprofen (Advil, Motrin)

Mild analgesics also hinder the body's ability to biosynthesise prostaglandin. **The special nerve endings that transmit the pain message are sensitised to prostaglandin so, by restricting its presence, the pain message is reduced.** This weakens the physiological chemical process that results in the sensation of pain.

These analgesics are non-narcotic (do not cause an addictive physical dependency) and are popular over-the-counter pain relievers because they are effective for moderate pain relief.

__Pros:__ __Cons:__
 * inexpensive
 * relatively safe
 * readily available
 * overdose may cause severe, even fatal side-effects, such as kidney problems

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Strong analgesics work by temporarily bonding to receptor sites in the brain, preventing the transmission of pain impulses without depressing the central nervous system. These drugs work on the central nervous system to relieve pain.
 * Strong Analgesics**

They are also known as narcotic analgesics because they cause an addictive physical dependence on the drug. These analgesics "trick" the brain into believe that you are still experiencing the pain, even if you are not. If the drug is discontinued, withdrawal symptoms such as agitation, anxiety, muscle aches, insomnia, sweating, cramps, diarrhea, nausea, and vomiting are experienced. Opioid withdrawal reactions are uncomfortable but not life threatening. Symptoms usually start within 12 hours of the last heroine usage or within 30 hours of last methadone exposure.

There are two kinds of narcotic analgesics: **opiates** and **opioids**, which are derivatives of opiates. Opiates are the white liquid extract of unripe seeds of the poppy plant. Opioids are used as strong analgesics. It functions by binding to opioid receptors in the central nervous system.

Examples:
 * Morphine
 * Codeine
 * Heroine