Neuropharmacology Flashcards
What is nociceptive pain?
Pain that is due to stimulation of nociceptors- produced due to stimulus that can cause tissue damage
What is neuropathic pain?
Pain the is not due to a stimulus, occurs in the absences of an ongoing noxious event
What is allodynia?
Painful responses to non-painful stimuli
What is hyperalgesia?
Pain is felt more strongly
What is the WHO pain ladder?
Non-opiate
Weak opiate
Strong opiate
(Titrate up and down as required)
What are the features of paracetemol?
Reduces mild pain
Anti-pyretic- reduces fever
No anti-inflammatory reaction
How do NSAIDs produce pain relief?
COX-2 Inhibition
COX-1 inhibition is an off-target response which reduces the production of the protective lining of the gastric mucosa
What are the features of NSAIDs?
Reduce inflammatory pain
No anti-pyrexial action
Nephrotoxic
Name two NSAIDs
Aspirin
Diclofenac - most potent
Ibuprofen
What are some risks with NSAID treatment?
Asthma trigger
Hypersensitivity reactions- Aspirin should not be given to children due to Reye’s reaction
Peptic ulcer formation
GI bleed
Reduced clotting due to anti-platelet action
Nephrotoxic
What should be given when prescribing an NSAID to a patient with an active or previous history of peptic ulcer diseasE?
A PPI
E.g. Lansoprazole
Give an example of a weak opiod
Codeine
Do opiates have any anti-inflammatory action?
No they do not
NSAIDs do this
What is a contra-indication to codeine?
Breast feeding as it can be excreted into the breast milk
What are some side effects of codeine?
Sedation
Constipation
Nausea
What is the mechanism of tramadol?
Opioid analgesic that also enhances 5HT and adrenergic pathways- causes euphoria so is subject to abuse
Give an example of a strong opiate
Morphine
Fentanyl
Pethidine
What is the mechanism of action of opiates?
Act on the mu and kappa receptors in the CNS
Why are strong opiates subject to abuse?
Tolerance develops which leads to withdrawal symptoms when removed
What is an adjuvant agent?
Drug intended for indications other than pain but are analgesic in selected circumstances
Generally used at lower doses than their usual indications
Give three examples of adjuvant agents
Tricyclic antidepressants- Amitriptyline
Anti epileptic drugs- Carbamazepine, Gabapentin
Anxiolytics- Benzodiazepam
What are some side effects of TCAs?
Example Amitriptyline Sedation Drowsiness Amtimuscarinic effects- dry mouth, urinary retention Dangerous in overdose
How does lamotrigine work?
Reduces pre-synaptic release of glutamate
Inhibits sodium channels
Used for all types of epilepsy
Safe to use in pregnancy
How does carbamazepine work?
Blocks sodium channels, prevents excitation
Safe to use in pregnancy
Used for tonic-clonic seizures
