D3+Analgesics

// Mild analgesics function by intercepting the pain stimulus at the source, often by interfering with the production of substances (for example, prostaglandins) that cause pain, swelling or fever. Strong analgesics work by temporarily bonding to receptor sites in the brain, preventing the transmission of pain impulses without depressing the central nervous system. // || // Aspirin has been found to be useful in preventing the recurrence of heart attacks and strokes. The disadvantages of aspirin include ulceration and stomach bleeding, allergic reactions and Reye’s syndrome in children (a potentially fatal liver and brain disorder). Paracetamol is very safe in the correct dose but can, in rare cases, cause blood disorders and kidney damage. Overdosage can lead to serious liver damage, brain damage and even death. // || // Stress the functional group modification to the structure of morphine that results in the semi-synthetic drug diamorphine (heroin). // || // Include the social as well as physiological effects of both short- and long-term use. // ||
 * D. 3 Analgesics ||
 * D . 3. 1 Describe and explain the different ways that analgesics prevent pain.
 * D.3.2 Describe the use of derivatives of salicylic acid as mild analgesics, and compare the advantages and disadvantages of using aspirin and paracetamol (acetaminophen).
 * D. 3. 3 Compare the structures of morphine, codeine and diamorphine (heroin, a semi-synthetic opiate).
 * D. 3. 4 Discuss the advantages and disadvantages of using morphine and its derivatives as strong analgesics.

__Purpose:__ pain reliever - a.k.a. pain killers/fever preventer

There are mild and strong analgesics:

__**Mild Analgesics**__  //Aspirin// is the ethanoate ester of salicylic acid  //Paracetamol// //(or acetaminophen in the USA)// a.k.a. Panadol or Tylenol  Tylenol (a paracetamol)

Derivatives of salicylic acid as a mild analgesic (Aspirin)
 * Can also be used to treat arthritis and rheumatism (because of its anti-inflammatory properties)
 * Can prevent blood clots
 * Can prevent strokes or recurrences of heart attacks
 * Possibly prevent prostate cancer

__How do mild analgesics prevent pain?__ (acts at the source) It intercepts pain stimulus. At the site of the injury, Aspirin prevents a particular enzyme, prostaglandin synthase, to form. Prostaglandin synthase synthesizes prostaglandins which produce fever, swelling and helps transmit pain to the brain. So by preventing the enzyme to be formed, prostaglandins can't be synthesized thus pain prevention!

Aspirin is a derivative of salicylic acid, being an ethanoate ester of salicylic acid

__Aspirin vs. Paracetamol__ Advantages Disadvantages <span style="color: blue; direction: ltr; font-family: Calibri; font-size: 16pt; margin-left: 0.0743in; margin-top: 0in; unicode-bidi: embed;">__**Strong Analgesics**__ <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-left: 0.0743in; margin-top: 0in; unicode-bidi: embed;">Prescription drugs; only used for **severe pain** caused by serious injuries, surgeries, heart attacks or chronic diseases (e.g. cancer). It's addictive and a tolerance will develop.
 * Aspirin || Paracetamol ||
 * Induces bleeding in stomach lining || Can lead to kidney damage and blood disorders(but rarely) ||
 * Allergies can develop resulting in bronchial asthma || Overdose can result in serious problems (brain damage, permanent liver and kidney damage and sometimes even death) ||
 * Children younger than 12: may develop Reye's disease (fatal brain and liver disorder) with symptoms of vomiting, lethargy, irritability and confusion || Preferred because the side effects are less problematic especially for young children ||
 * Overdose can be fatal since the salicylic acid leads to acidosis (increase in blood acidity) - basically, salicylic acid lowers blood pH ||  ||
 * Can treat/prevent other things such as: arthritis, rheumatism, blood clotting, strokes, heart attack recurrences and possibly prostate cancer ||  ||

<span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-left: 0.0743in; margin-top: 0in; unicode-bidi: embed;">// Morphine (natural) // <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-left: 0.0743in; margin-top: 0in; unicode-bidi: embed;">// Coedine (natural) //

<span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-left: 0.0743in; margin-top: 0in; unicode-bidi: embed;">// Diamorphine (heroin, a semi-synthetic **opiate**)- more powerful painkiller //

<span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-left: 0.0743in; margin-top: 0in; unicode-bidi: embed;">__How do strong analgesics prevent pain?__ (acts at the receptor) <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-left: 0.0743in; margin-top: 0in; unicode-bidi: embed;">Strong analgesics prevent pain impulse transmissions without depressing the central nervous system**.** They temporarily interact with receptor sites in the brain, bonding to those sites. Therefore, pain signals within in the brain and spinal cord are blocked. <span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-left: 0.0743in; margin-top: 0in; unicode-bidi: embed;">//(Opiates will depress the nervous system)//

<span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-left: 0.0743in; margin-top: 0in; unicode-bidi: embed;">__Structure of Strong Analgesics:__ all strong analgesics have similar basic structure and function in which the amine group is the active part. **(refer to textbook for diagrams pg.121 in study guide)**. Modifications can be made to morphine by a diesterification reaction (a reaction where ester is formed), so 2 ester groups are added which replace 2 OH in morphine to form diamorphine (heroin) thus it is semi-synthetic. Same basic structure in codeine as morphine but one of the OH groups are replaced by an ether group (-OCH3).

__<span style="direction: ltr; font-family: Calibri; font-size: 11pt; margin-left: 0.0743in; margin-top: 0in; unicode-bidi: embed;">Disadvantages and advantages of Strong Analgesics (Morphine and opiates: morphine derivatives (e.g. heroin)) __ <span style="-webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px; border-collapse: collapse; line-height: normal;">
 * **Disadvantages** || **Advantages** ||
 * Addictive (heroin more addictive) || Pain reliever for **serious** injuries/pain (heroin is more powerful) ||
 * Leads to tolerance which results in a need for higher dosage (which can be lethal) || Creates euphoric feeling (feeling of well-being) ||
 * Depresses nervous system **(opiates)** || Creates job opportunities (for people who grow it, sell it and synthesize derivatives) ||
 * Slows breathing and heart rate || Slows breathing and heart rate ||
 * Surpresses cough reflex || Constipation ||
 * Nausea and vomiting ||  ||
 * Overdose results in coma and/or even death ||  ||
 * Loss of sex drive ||  ||
 * Disrupts menstrual cycle ||  ||
 * Poor eating habits ||  ||
 * Increases risk of AIDS, hepatitis etc. (sharing needles) ||  ||
 * Social: theft, prostitution ||  ||
 * Addicts experiencing withdrawal (within 6 to 24 hours after supply is stopped): hot and cold sweats, diarrhea, anxiety and cramps ||  ||