Analgesics
Basically, painkillers
Arguably the most important human discovery because before painkillers, people died
of shock of pain from surgery
Pain
o Complex biochemical, histological, neurophysical process where dangerous
stimuli (thermal, medical, chemical, etc.) trigger nociceptors (sensory neuron for
pain) which carry the nerve impulses to the brain
o Prostaglandins and leukotrienes are produced to sensitize sensory neurons for
pain so that gentle stimulus cause pain
Pain killers reduce prostaglandin and leukotriene reception
Mild analgesics: derived from salicylic acid
o Aspirin, ibuprofen
o Inhibits prostaglandin synthesis
o Aspirin
Found in willow tree bark and leaves
Antipyretic: reduce fever
Anti-inflammatory: reduce swelling
Anti-clotting: reduce blood clots
Side effects: stomach bleeding, allergies, Reye’s Syndrome in children
(liver swelling)
o Alternatives to aspirin:
Paracetamol: smaller side effects, no stomach bleeding, but contains risk
of liver damage, and must avoid consumption with alcohol
Ibuprofen: best of both worlds: kills pain and is anti-inflammatory
Local anaesthetics: cocaine
o Ex: procaine, benzocaine
o Mechanism: Prevents nerve impulse transmission, binds to fast sodium channel
General anaesthetics: nitrous oxide, laughing gas
o Ex: isoflurane, desflurane, xenon
o Mechanism: unknown, may be physical effect instead of chemical, like swelling
neuron membranes
Opiates
o Activates the µ-opioid receptors in the brain that bind to β-endorphin, the “feel
good” neurotransmitter
o Strong, military grade painkillers
o Derived from the poppy plant, from crude resin extracted by cutting into the
seed pod
o Natural form: morphine, so heroin and codeine are derivatives
o Has the ability to change brain chemistry (VTA)
o Natural equivalence in brain: endorphins
o Codeine is present in prescription cough syrups
Basically, painkillers
Arguably the most important human discovery because before painkillers, people died
of shock of pain from surgery
Pain
o Complex biochemical, histological, neurophysical process where dangerous
stimuli (thermal, medical, chemical, etc.) trigger nociceptors (sensory neuron for
pain) which carry the nerve impulses to the brain
o Prostaglandins and leukotrienes are produced to sensitize sensory neurons for
pain so that gentle stimulus cause pain
Pain killers reduce prostaglandin and leukotriene reception
Mild analgesics: derived from salicylic acid
o Aspirin, ibuprofen
o Inhibits prostaglandin synthesis
o Aspirin
Found in willow tree bark and leaves
Antipyretic: reduce fever
Anti-inflammatory: reduce swelling
Anti-clotting: reduce blood clots
Side effects: stomach bleeding, allergies, Reye’s Syndrome in children
(liver swelling)
o Alternatives to aspirin:
Paracetamol: smaller side effects, no stomach bleeding, but contains risk
of liver damage, and must avoid consumption with alcohol
Ibuprofen: best of both worlds: kills pain and is anti-inflammatory
Local anaesthetics: cocaine
o Ex: procaine, benzocaine
o Mechanism: Prevents nerve impulse transmission, binds to fast sodium channel
General anaesthetics: nitrous oxide, laughing gas
o Ex: isoflurane, desflurane, xenon
o Mechanism: unknown, may be physical effect instead of chemical, like swelling
neuron membranes
Opiates
o Activates the µ-opioid receptors in the brain that bind to β-endorphin, the “feel
good” neurotransmitter
o Strong, military grade painkillers
o Derived from the poppy plant, from crude resin extracted by cutting into the
seed pod
o Natural form: morphine, so heroin and codeine are derivatives
o Has the ability to change brain chemistry (VTA)
o Natural equivalence in brain: endorphins
o Codeine is present in prescription cough syrups
