Analgesics Flashcards
What is the primary purpose of pain?
Its a protective mechanism that warns of damage or disease and it starts of the healing process.
Differentiate between acute and chronic pain.
Acute pain is sudden and is resolvable, chronic pain is persistent and harder to treat.
What are the two main types of analgesic treatments?
Non-opioids (NSAIDs, paracetomol) and opioid derived drugs.
What is the mechanism of NSAIDs
They inhibit the cox enzyme, reducing prostaglandins that cause pain and inflammation.
Name three types of NSAIDs based on COX inhibition
Aspirin - irreversible, non selective
Ibuprofen - reversible, non selective
Celecoxib - selective cox 2 inhibitor
Whats the difference between cox 1 and cox 2?
Cox 1 is constitutive, cox 2 is inducible, inflammation, pain, fever)
What is aspirin’s mechanism of action?
Irreversibly acetylates cox 1 and cox 2, inhibiting prostaglandin and thromboxane synthesis.
What are the common side effects of long term aspirin use?
Gastrointestinal bleeding, peptic ulcers, renal toxicity and increased blood pressure.
How does ibuprofen compare to aspirin
Similar mechanism and effects but it is reversible and lessened side effects.
What makes paracetamol different from NSAIDs?
It works mainly in the CNS, has weaker anti-inflammatory effects and doesn’t affect platelets or cause GI irritation.
What is morphine’s mechanism of action?
It binds to opioid receptors in the brain and spinal cord, inhibiting pain transmission.
Which opioid receptor is primarily responsible for morphine’s effects?
The u-opioid receptor.
What are the key CNS effects of morphine?
Analgesia, euphoria, sedation, respiratory depression and miosis (pinpoint pupils)
What causes opioid tolerance?
Receptor desensitization from prolonged use, requiring a higher dose for the same effect.
What is opioid dependence?
Physical and psychological withdrawal symptoms after cessation, including cravings and hyperexcitability.
What is codeine’s relationship to morphine?
Its a naturally occurring alkaloid that is primarily converted to morphine in the body.
What makes methadone unique among opioids?
It has a long half life, 24 hours, and is used in opioid replacement therapy due to its prolonged, less intense withdrawal.
What are the roles of endogenous opioids like endorphins?
They modulate pain by activating opioid receptors to reduce neurotransmitter release.
What are the three classical opioid receptor subtypes?
Mu, delta and kappa
What does u-opioid receptor activation lead to in drug reward pathways?
Disinhibition of dopamine neurons in the VTA, increasing dopamine release in nucleus accumbens.
