1. Medicines and drugs
Analgesics

2. Analgesics – reduce pain

3. Pain
Pain is detected in the brain when nerve messages are sent from pain receptors in the body.
The receptors are stimulated by chemicals (prostaglandins) released from cells that are damaged.

4. Mild analgesics
Mild analgesics, such as aspirin, paracetamol (acetaminophen) and ibuprofen , function by stopping the transmission of pain from the source to the brain as they intercept the pain stimulus at the source.
They do this by interfering with the production of substances, such as prostaglandins, that are produced by injured tissues and that cause pain, swelling or fever.
These are all non-narcotics – do not interfere with the function of the brain

5. Strong analgesics - Opiates
Strong analgesics such as morphine, codeine, and diamorphine (heroin) work by temporarily bonding to receptor sites in the brain preventing the transmission of pain impulses.
This prevents the transmission of pain impulses i.e. blocking the signal without depressing the central nervous system.
Alters your perception of pain.
These are called narcotics b/c they act on the brain.

6. Mild or strong? Mild analgesics eliminate pain at source
Strong analgesics alter our ability to perceive pain

7. Structures of analgesics
aspirin
paracetamol
benzene
ester
carboxylic acid
benzene
hydroxyl
amide
carbonyl

8. Structure of analgesics
ibuprofen
benzene
carboxylic acid

9. A derivative = a new compound from changing another compound
Aspirin – a derivative
salicylic acid…. (caused vomiting) into aspirin
A derivative = a new compound from changing another compound
To convert salicylic acid (2-hydroxybenzoic acid) into aspirin the hydrogen atom of the OH group is replaced by a COCH3 group to form an ester functional group which makes the compound less irritating to the stomach and easier to take.

10. aspirin advantage disadvantage
reduces fever more effectively – antipyretic (=drug which reduces fever)
also useful in preventing the recurrence of heart attacks and strokes and also thins the blood (beneficial side-effects) and reduces blood clotting
also anti-inflammatory – reduces inflammation or swelling
ulceration
stomach bleeding due to its acidic properties
allergic reactions
Reye’s syndrome in children (a potentially fatal liver and brain disorder) - not so suitable for children (baby aspirin is available)

11. paracetamol advantage disadvantage reduces fever – antipyretic
very safe in the correct dose as it does not upset the stomach or cause bleeding
suitable for children
can, in rare cases, cause blood disorders and kidney damage.
easier to overdose and over dosage can lead to serious liver/kidney damage, brain damage and even death.
not a good anti-inflammatory

12. Structures of Strong Analgesics
All structures above are in the IB data booklet
Morphine + ethanoic acid Heroin and Water

13. Strong analgesics morphine diamorphine/heroin codeine benzene
hydroxyl /alcohol (2)
ether
double bond
tertiary amine
ester (2)
Benzene
hydroxyl (1)
ether (1)
Increase in effects: Codeine  Morphine  Heroin

14. Structures of Strong Analgesics

15. Structures of Strong Analgesics

16. Derivatives of Morphine
Morphine is a natural substance made from opium in poppy plants.
Diamorphine (heroin) and codeine are derivatives of morphine.
An opiate is a class of drugs or chemicals which have the same physiological effect as morphine.
Heroin’s structure is only slightly different from morphine. Both the hydroxyl or alcohol groups in morphine have been replaced with ester groups. This is achieved by reacting the morphine with ethanoic acid; as a result an esterification occurs during which also water is produced.
Demerol is also a strong analgesic, but it is synthetically made.

17. Using morphine - advantages
strong analgesics and therefore can relieve extreme pain
wide therapeutic window
relieves anxiety
induces relaxation
can be administered intravenously which results in faster distribution of drug

18. Using morphine - advantages
Short Term Effects:
Euphoria – happy (this could be a disadvantage)
Relieves pain from heart attacks and injuries
Prevents coughing

19. Morphine - disadvantages
Constipation, increase or decrease in weight, kidney failure, loss of libido
addiction or physical dependence which leads to withdrawal symptoms when drug is not taken e.g. restlessness, sweating, fever, cramping, …
tolerance can become an issue with this type of drug as more of the drug needs to be taken to achieve the same effect; in order to achieve the desired effect heroin users may take doses which exceed the lethal dose
Social:
users are more likely to commit crimes to pay for gradually increasing doses of the drug
loss of job
diversion of energy and money
when administered intravenously can lead to transmission of dangerous infections e.g. AIDS.