1. Medicinal chemistry
Opiates

2. Learning out comes Understand what is meant by an opiate
Understand the mode of action of strong analgesics such as morphine and codeine
Compare the structures of morphine, codeine and diamorphine
Explain why diamorphine is more potent than morphine
Understand how diamorphine and codeine can be synthesised from morphine
Explain the advantages and disadvantages of using opiates

3. Analgesics Analgesics are common pain relievers.
Many analgesics also have antipyretic properties as well. They can be used to reduce fever
Some analgesics are also anti-inflammatory drugs as well

4. Classification of Analgesics
Strong
Analgesics
Mild
Analgesics
Opium
Aspirin
Ibuprofen
Heroin
Codeine
Acetaminophen

5. Strong analgesics
Whereas mild analgesics, such as aspirin, are used for relatively mild pain, such as headache or toothache, opiate/opioid analgesics are strong analgesics used for moderate to severe pain, such as in terminally ill patients. Mild analgesics may be combined with strong analgesics in some preparations – for example, paracetamol and codeine are often used together.

6. Strong Analgesics Only Available by prescription
Used to relieve severe pain associated with injuries, heart attacks, or chronic diseases such as cancer
Most strong analgesics are derived from the opium poppy or synthetically produced
Basically three types:
Natural,
semi-synthetic,
synthetic

7. Opiates
Opiates are natural narcotic (sleep-inducing) analgesics derived from the opium poppy.
The term ‘narcotic’ can be used in different ways. It is used here to describe analgesic drugs derived from opium, but nowadays it is often used in everyday language to indicate any illicit/strictly controlled drug.

8. Origin of Opiates
Opiates are derived from the juice of the unripe seed pods of the poppy Papaver somniferum. This juice is known as opium (the Greek word for ‘juice’) and contains morphine as one of the ingredient.
Morphine was first isolated in 1803 and is chiefly responsible for the biological effects of opium

9. How it works
Strong analgesics work by temporarily bonding to receptor sites in the brain, preventing the transmission of pain impulses without depressing the central nervous system.
Morphine and codeine are strong analgesics, which act by temporarily binding to opioid receptors in the brain. This blocks the transmission of pain signals in the brain and increases the pain perception threshold
Even though pain in the affected tissue is still occurring and being transmitted via the peripheral nervous system, the patient is not as aware of it

10. Opiates cause a number of effects on the body through binding to opioid receptors. These include analgesia, sedation, a feeling of well-being and suppression of the cough reflex. They are used medically for pain relief and the treatment of coughs and diarrhea.

11. Structures of morphine and its derivatives

12. Morphine Naturally occurring in the poppy- Only needs to be isolated
Very strong pain reliever but also very addictive (2nd to Heroin)
Usually injected but can be smoked, sniffed or swallowed
Commonly used in hospitals
Large illegal street culture

13. Codeine Most commonly used strong analgesic
Similar to Morphine except for the replacement of a (OH-) group for (OCH3) group
Commonly used with Tylenol as a more mild analgesic
1/6 as strong as Morphine and less addictive

14. Synthesis of codeine
Codeine synthesis Codeine can also be synthesised from morphine In the original process, morphine was reacted with iodomethane (the methylating agent) in the presence of a base. Phenols are slightly acidic and so the presence of a strong base converts the OH of the phenol to O−. The reaction is nucleophilic substitution, with the O− attacking the δ+ carbon atom of the CH3I.

15. Heroin ( diamorphine)
Originally sold as cough suppressant and pain killer 10 times stronger than Morphine
Incredibly addictive (many times, other strong analgesics are needed for withdrawal)

16. Synthesis of diamorphine
Synthesized from morphine in a esterification reaction with acetyl chloride

17. Heroin
It is absorbed by the brain very quickly resulting in a potent high
Many other problems are associated with heroin addiction including as prostitution and AIDS.

18. Advantages of opiates
Opiates such as morphine and diamorphine are used medically for the relief of severe pain – they are especially effective in visceral pain (pain in internal organs, such as the liver and lungs). They are commonly used to relieve the pain associated with cancer in terminally ill patients.
Morphine may also be used for the short-term control of diarrhea due to its constipating effect, and to control distressing coughing by lung cancer patients, due to its cough-suppressant effect.
Milder opiates such as codeine are used to relieve moderate pain. Codeine is also used as a cough suppressant for dry coughs and as an anti diarrhea drug.

19. Side Effects of Opiates Analgesics
Short term
Dulling of Pain
Euphoria
Slow Nervous system
Slowed heart rate
Loss of cough reflex
Nausea
Overdoses can lead to death
Possibility of stroke
Overall slowdown of biological systems
Long Term
Addiction and very strong withdrawal effects
Constipation
Loss of libido
Disruptions in menstruation
“Cross-tolerance”
Loss of appetite
Problems associated with buying street drugs i.e. sharing needles AIDS and prostitution.

20. Methadone Compared to most strong analgesics it is weaker.
Has been synthesized to not have euphoric properties and mild withdrawal effects but is still addictive.
Used as an analgesic but most commonly to help in the withdrawal for Heroin addicts.