D3 Opiates Flashcards
How do strong analgesics work?
They kill the pain by preventing the transmission of pain impulses at the brain, rather than at the source.
What are opiates?
Opiates are natural strong analgesics derived from opium which is found in poppy seeds
What are the differences between mild and strong analgesics?
Site and mechanism of action, tolerance and dependance, and legal status
SITE OF ACTION
* Site of injury
* Brain
MECHANISM OF ACTION
* Inhibits prostaglandin release
* Interfere with opiod receptors in the brain
TOLERANCE AND DEPENDANCE
* Less likely
* More likely
LEGAL STATUS
* More easily available
* Strict regulation, some use illegal means to obtain it
Mild - Strong (order)
How do opiates work?
Normally, brain cells would recieve pain signals. However, when opiated bind to the opioid receptors, the transmission of pain signals is blocked.
What are other possible effects of analgesics
Why are they also considered narcotics?
Because theu can also cause possible changes in behaviour and mood
The blood-brain barrier
passing through the blood-brain barrier (polarity and solubility)
The brain is sorrounded by a blood-brain barrier which protects it by restricting the chemicals that go through
This structure is mainly made of non-polar molecules so the less polar and more lipo-soluble a substance is, the more likely it is to enter the brain
What are the three main opiodes studied?
Codeine, morphine and dimorphine
What are the therapeutic uses of codeine?
- sometimes used in preparation eith a non-narcotic drug such as aspirin or paracetamol in the second stage of the pain management ladder
- Also used for cough medications and the short-term treatment for diarrhea
What are the therapeutic uses of morphine?
- Used in the management of severe pain
What are the dangers of morphine?
It can be habit-forming and can lead to dependace, so it must be regulated by medical professionals
What are the therapeutic uses of diamorphine?
- Used legally in a few countries for the relief of severe pain
What are the dangers of dimorphine?
- It initially produces euphoric effects, but it has a very high potential for causing addiction and increased tolerance
- Dependance leads to withdrawal symptoms and many associated problems
Tell me everything about morphine
derived from? polarity?
- It is the principal drug derived from opium
- The two OH groups in morphine give it some polarity, which limits it’s ability to cross the blood-brain barrier
- Intravenous injection is 6 times more bioavailable as when taken orally
Tell me everything about morphine
derived from? polarity? analgesic strength?
- Codeine is found at low levels of opium (0.5%) but is more commonly prepared from morphine
- One of the OH groups is converted into the methyl ether by methylation which makes the compound less polar, allowing it to cross the blood-brain barrier more easily
- This ^ makes codeine a weaker analgesic due to the drop in binding capabilities at the opioid receptors
What do codeine, morphine and dimorphine have in common?
They have common basic structures which accounts to their similar properties.
